|
Displacement of [3H]flunitrazepam at GABA-A benzodiazepine receptor in rat brain cortical membranes
|
Rattus norvegicus
|
2.5
nM
|
|
Journal : J. Med. Chem.
Title : Synthesis and binding activity of some pyrazolo[1,5-c]quinazolines as tools to verify an optional binding site of a benzodiazepine receptor ligand.
Year : 1996
Volume : 39
Issue : 15
First Page : 2915
Last Page : 2921
Authors : Colotta V, Catarzi D, Varano F, Filacchioni G, Cecchi L, Galli A, Costagli C.
Abstract : The synthesis and binding activity at the benzodiazepine receptor of some 2-substituted pyrazolo[1,5-c]quinazolines are reported. The structure-activity relationships and in vitro efficacy of the title compounds, which are devoid of the proton acceptor atom at position 1, are similar to those of some previously reported tricyclic heteroaromatic compounds. This suggests that a proton acceptor at position 1 is an optional binding site of a benzodiazepine receptor ligand which only affects potency.
|
Inhibition of radiolabeled antagonist [3H]-Ro- 15-1788 binding to benzodiazepine receptor from rat cortical membranes
|
None
|
3.8
nM
|
|
Journal : J. Med. Chem.
Title : Novel benzodiazepine receptor partial agonists: oxadiazolylimidazobenzodiazepines.
Year : 1989
Volume : 32
Issue : 10
First Page : 2282
Last Page : 2291
Authors : Watjen F, Baker R, Engelstoff M, Herbert R, MacLeod A, Knight A, Merchant K, Moseley J, Saunders J, Swain CJ.
Abstract : The synthesis and biochemical evaluation of a series of oxadiazole derivatives of imidazobenzodiazepines related to the benzodiazepine antagonist Ro 15-1788 (2a) are reported. Although the oxadiazole ring is seen as an isosteric replacement for the ester linkage, significant differences in structure-activity trends were observed. Specifically, oxadiazoles 9-12 invariably had increased receptor efficacy (as witnessed by measurements of the GABA shift) relative to the corresponding ester. Additionally, and in direct contrast to the classical agonists such as diazepam, affinity for the benzodiazepine receptor was enhanced by a 7- rather than 8-halo substituent. The results are discussed in terms of a six-point receptor-binding model originally based on the X-ray structure of 2a. For comparison, the crystal structures of two representative oxadiazole derivatives, 10h and 12o, having a 6-oxo and 6-phenyl group, respectively, were determined and the data incorporated into a modified binding model to account for the greater efficacy of these compounds. It is concluded that the antagonist behavior of 2a relies upon the hydrogen-bond-acceptor properties of the ester carbonyl oxygen whereas for the oxadiazole series this site is localized at the imidazole nitrogen.
|
Binding affinity for Diazepam insensitive (DI) isoform of the benzodiazepine (Bz) binding site on GABAA receptors
|
None
|
58.0
nM
|
|
Journal : J. Med. Chem.
Title : Synthetic and computer-assisted analysis of the structural requirements for selective, high-affinity ligand binding to diazepam-insensitive benzodiazepine receptors.
Year : 1993
Volume : 36
Issue : 13
First Page : 1820
Last Page : 1830
Authors : Wong G, Koehler KF, Skolnick P, Gu ZQ, Ananthan S, Schönholzer P, Hunkeler W, Zhang W, Cook JM.
Abstract : Several 1,4-diazepines were recently reported to bind with high affinities to the "diazepam-insensitive" (DI) isoform of the benzodiazepine receptor (BzR) (Korpi, E.R.; Uusi-Oukari, M.; Wegelius, K. Eur. J. Pharm. 1992, 213, 323-329. Wong, G.; Skolnick, P. Eur. J. Pharmacol. Mol. Pharm. Sec. 1992, 225, 63-68). However, only the putative ethanol antagonist 1 (Ro 15-4513) displayed modest selectivity for the DI site compared to other "diazepam-sensitive" (DS) BzR isoforms. In order to probe the requirements for selective, high-affinity binding to the DI site, the affinities of 47 benzodiazepines have been determined at both DI and DS BzR sites. In addition, single X-ray crystallographic analyses for three of these derivatives, 5 (Ro 17-1812), 6 (Ro 16-6028), and 42 (Ro 14-5974), are reported. The radioligand binding studies reveal that modifications to the 3-, 7-, and 8-positions of 6-oxoimidazo[1,5-alpha] [1,4]benzodiazepines have a marked influence on the Ki(DI)/Ki(DS) ratios. In order to more precisely determine the structural requirements for both high affinity and selectivity at DI BzR relative to DS, 3D-QSAR analyses were carried out on ligand affinities at both of these BzR isoforms. This analysis was based, in part, on the new X-ray crystallographic data. Satisfactory cross-validated regression equations were obtained individually for the logarithms of ligand affinities at DI and DS as well as for the differences of the logarithms of their affinities at these two isoforms (cross-validated R2 > 0.70 for all three regression equations). The steric and electrostatic 3D-QSAR DI and DS maps are in qualitative accord with the structure-activity relationship (SAR) data. Furthermore, the DI and DI/DS maps may be useful in the design of ligands with enhanced DI affinity and DI/DS selectivity, respectively.
|
Binding affinity for Diazepam sensitive (DS) isoform of the benzodiazepine (Bz) binding site on GABAA receptors
|
None
|
0.8
nM
|
|
Journal : J. Med. Chem.
Title : Synthetic and computer-assisted analysis of the structural requirements for selective, high-affinity ligand binding to diazepam-insensitive benzodiazepine receptors.
Year : 1993
Volume : 36
Issue : 13
First Page : 1820
Last Page : 1830
Authors : Wong G, Koehler KF, Skolnick P, Gu ZQ, Ananthan S, Schönholzer P, Hunkeler W, Zhang W, Cook JM.
Abstract : Several 1,4-diazepines were recently reported to bind with high affinities to the "diazepam-insensitive" (DI) isoform of the benzodiazepine receptor (BzR) (Korpi, E.R.; Uusi-Oukari, M.; Wegelius, K. Eur. J. Pharm. 1992, 213, 323-329. Wong, G.; Skolnick, P. Eur. J. Pharmacol. Mol. Pharm. Sec. 1992, 225, 63-68). However, only the putative ethanol antagonist 1 (Ro 15-4513) displayed modest selectivity for the DI site compared to other "diazepam-sensitive" (DS) BzR isoforms. In order to probe the requirements for selective, high-affinity binding to the DI site, the affinities of 47 benzodiazepines have been determined at both DI and DS BzR sites. In addition, single X-ray crystallographic analyses for three of these derivatives, 5 (Ro 17-1812), 6 (Ro 16-6028), and 42 (Ro 14-5974), are reported. The radioligand binding studies reveal that modifications to the 3-, 7-, and 8-positions of 6-oxoimidazo[1,5-alpha] [1,4]benzodiazepines have a marked influence on the Ki(DI)/Ki(DS) ratios. In order to more precisely determine the structural requirements for both high affinity and selectivity at DI BzR relative to DS, 3D-QSAR analyses were carried out on ligand affinities at both of these BzR isoforms. This analysis was based, in part, on the new X-ray crystallographic data. Satisfactory cross-validated regression equations were obtained individually for the logarithms of ligand affinities at DI and DS as well as for the differences of the logarithms of their affinities at these two isoforms (cross-validated R2 > 0.70 for all three regression equations). The steric and electrostatic 3D-QSAR DI and DS maps are in qualitative accord with the structure-activity relationship (SAR) data. Furthermore, the DI and DI/DS maps may be useful in the design of ligands with enhanced DI affinity and DI/DS selectivity, respectively.
|
Binding affinity for Diazepam-Insensitive fraction of GABA-A benzodiazepine receptors
|
Rattus norvegicus
|
58.0
nM
|
|
Journal : J. Med. Chem.
Title : Synthesis and evaluation of imidazo[1,5-a][1,4]benzodiazepine esters with high affinities and selectivities at "diazepam-insensitive" benzodiazepine receptors.
Year : 1993
Volume : 36
Issue : 8
First Page : 1001
Last Page : 1006
Authors : Gu ZQ, Wong G, Dominguez C, de Costa BR, Rice KC, Skolnick P.
Abstract : A series of imidazo[1,5-a][1,4]benzodiazepine esters have been synthesized with varying ester side chains and 8-position substituents. The affinities of these compounds were evaluated at both "diazepam-insensitive" (DI) and diazepam-sensitive (DS) subtypes of the benzodiazepine receptor (BZR). A profound steric effect of the 3-position ester side chain moiety was observed on ligand affinity at DI. In contrast, ester size had a less robust effect on ligand affinity at DS. The tert-butyl ester compound 8 displayed the highest affinity (Ki = 1.7 nM) for DI within a series of 8-chloro esters. Furthermore, halogens at the 8-position resulted in an enhancement of both ligand affinity and selectivity at DI among the series of tert-butyl esters examined. The 8-nitro derivative 23 and 8-isothiocyanato congener 25 had high affinities for both DI and DS but exhibited little subtype selectivity (10.8 and 2.7 nM at DI versus 14 and 3.7 nM at DS, respectively). The 8-azido tert-butyl ester 29 exhibited a significantly higher affinity (Ki = 0.43 nM) and selectivity (DI/DS ratio of 0.2) than the corresponding ethyl ester, the prototypic DI ligand 1 (Ro 15-4513). Among the compounds synthesized, 29 is the highest affinity ligand for DI described to date while its 8-bromo analog 18 is the most selective ligand (DI/DS ratio of 0.17) for this novel BZR subtype.
|
Binding affinity for Diazepam-Sensitive fraction of GABA-A benzodiazepine receptors
|
None
|
0.8
nM
|
|
Journal : J. Med. Chem.
Title : Synthesis and evaluation of imidazo[1,5-a][1,4]benzodiazepine esters with high affinities and selectivities at "diazepam-insensitive" benzodiazepine receptors.
Year : 1993
Volume : 36
Issue : 8
First Page : 1001
Last Page : 1006
Authors : Gu ZQ, Wong G, Dominguez C, de Costa BR, Rice KC, Skolnick P.
Abstract : A series of imidazo[1,5-a][1,4]benzodiazepine esters have been synthesized with varying ester side chains and 8-position substituents. The affinities of these compounds were evaluated at both "diazepam-insensitive" (DI) and diazepam-sensitive (DS) subtypes of the benzodiazepine receptor (BZR). A profound steric effect of the 3-position ester side chain moiety was observed on ligand affinity at DI. In contrast, ester size had a less robust effect on ligand affinity at DS. The tert-butyl ester compound 8 displayed the highest affinity (Ki = 1.7 nM) for DI within a series of 8-chloro esters. Furthermore, halogens at the 8-position resulted in an enhancement of both ligand affinity and selectivity at DI among the series of tert-butyl esters examined. The 8-nitro derivative 23 and 8-isothiocyanato congener 25 had high affinities for both DI and DS but exhibited little subtype selectivity (10.8 and 2.7 nM at DI versus 14 and 3.7 nM at DS, respectively). The 8-azido tert-butyl ester 29 exhibited a significantly higher affinity (Ki = 0.43 nM) and selectivity (DI/DS ratio of 0.2) than the corresponding ethyl ester, the prototypic DI ligand 1 (Ro 15-4513). Among the compounds synthesized, 29 is the highest affinity ligand for DI described to date while its 8-bromo analog 18 is the most selective ligand (DI/DS ratio of 0.17) for this novel BZR subtype.
|
Agonistic activity against specific binding of radioligand [3H]Ro-151788 to GABA-A Benzodiazepine receptor in rat cortex
|
None
|
1.82
nM
|
|
Journal : J. Med. Chem.
Title : Structure-activity relationship studies at the benzodiazepine receptor (BZR): a comparison of the substitutent effects of pyrazoloquinolinone analogs.
Year : 1993
Volume : 36
Issue : 11
First Page : 1669
Last Page : 1673
Authors : Fryer RI, Zhang P, Rios R, Gu ZQ, Basile AS, Skolnick P.
Abstract : The synthesis of a series of 2-phenylpyrazolo[4,3-c]quinolin-3-one derivatives and their in vitro biological evaluation as ligands for the benzodiazepine receptor are described. The in vitro activities, as determined by an analysis of GABA shift ratios, and binding affinities of these compounds to BZR are compared in terms of the electronic, lipophilic, and steric effect changes of their substituents.
|
In vitro affinity against Benzodiazepine receptor binding to rat cortical membranes (using [3H]- flumazenil as radioligand).
|
None
|
1.2
nM
|
|
Journal : J. Med. Chem.
Title : Structure-activity relationships and molecular modeling analysis of flavonoids binding to the benzodiazepine site of the rat brain GABA(A) receptor complex.
Year : 1999
Volume : 42
Issue : 21
First Page : 4343
Last Page : 4350
Authors : Dekermendjian K, Kahnberg P, Witt MR, Sterner O, Nielsen M, Liljefors T.
Abstract : The affinities for the benzodiazepine binding site of the GABA(A) receptor of 21 flavonoids have been studied using [(3)H]flumazenil binding to rat cortical membranes in vitro. We show that flavonoids with high affinity for the benzodiazepine receptor in vitro spanning the whole efficacy range from agonists (1q) to inverse agonists (1l) can be synthesized. The receptor binding properties of the flavonoids studied can successfully be rationalized in terms of a comprehensive pharmacophore model recently developed by Cook and co-workers (Drug Des. Dev. 1995, 12, 193-248), supporting the validity of this model. However, in contrast to the requirement by the model that an interaction with the hydrogen bond-accepting site A2 is necessary for compounds to display inverse agonistic activity, 6-methyl-3'-nitroflavone (1l), which cannot engage in such an interaction, nevertheless displays inverse agonism. The analysis of the binding affinities of 3'- and 4'-substituted flavones in terms of the pharmacophore model has yielded new information for the further development of the pharmacophore model.
|
In vitro binding affinity against benzodiazepine receptor using [3H]diazepam as radioligand
|
None
|
1.94
nM
|
|
Journal : J. Med. Chem.
Title : Benzodiazepine receptor binding and anticonflict activity in a series of 3,6-disubstituted pyridazino[4,3-c]isoquinolines devoid of anticonvulsant properties.
Year : 1985
Volume : 28
Issue : 9
First Page : 1314
Last Page : 1319
Authors : Toja E, Tarzia G, Barone D, Luzzani F, Gallico L.
Abstract : A series of 3,6-disubstituted pyridazino[4,3-c]isoquinolines were synthesized and tested for their ability to inhibit the binding of [3H]diazepam to rat brain receptors in vitro. Compounds bearing a phenyl, 4-methoxyphenyl, or methyl group at position 3 and a dialkylamino group at position 6 showed the highest affinity in the binding assay and were subsequently evaluated for their anticonflict and anticonvulsant effects. All of these compounds (5a-1 and 5q) were active in the Vogel rat conflict procedure, but none prevented convulsions in mice induced either by metrazol or bicuculline. 3-Phenyl-6-pyrrolidinylpyridazino[4,3-c]isoquinoline (5d) with a Ki = 11.4 nM in the binding assay exhibited the best potency in the anticonflict assay (MED 5 mg/kg ip) and did not produce neuromuscular impairment at the highest dose tested (50 mg/kg ip).
|
Inhibition of [35S]-TBPS binding to GABA-A central Benzodiazepine Receptor of bovine cerebral cortex membranes
|
Bos taurus
|
15.0
%
|
|
Journal : J. Med. Chem.
Title : 3-Aryl-[1,2,4]triazino[4,3-a]benzimidazol-4(10H)-ones: tricyclic heteroaromatic derivatives as a new class of benzodiazepine receptor ligands.
Year : 2000
Volume : 43
Issue : 1
First Page : 96
Last Page : 102
Authors : Primofiore G, Da Settimo F, Taliani S, Marini AM, La Motta C, Novellino E, Greco G, Gesi M, Trincavelli L, Martini C.
Abstract : A series of 3-substituted [1,2,4]triazino[4,3-c]benzimidazoles V were prepared and tested at the central benzodiazepine receptor (BzR). These compounds were designed as rigid analogues of the previously described N-benzylindolylglyoxylylamide derivatives IV. The title compounds V showed an affinity which depended directly on the presence of the N(10)-H group and an aromatic ring at position 3. Some of them elicited a 2- or 3-fold higher affinity with respect to that of the indolylglyoxylylamide derivatives IV (R = H). The GABA ratio and [(35)S]-tert-butylcyclophosphorothionate binding data revealed an efficacy profile of partial inverse agonists/antagonists for compounds 1c,e,f,j,k, and of a partial agonist for 2c. This last compound proved to be effective in antagonizing pentylenetetrazole-induced seizures in mice. Attempts were made to interpret the structure-affinity relationships of compounds V in the light of possible tautomeric equilibria involving the ligands.
|
In vitro inhibition of [3H]-Ro- 15-1788 binding to GABA-A Benzodiazepine receptor of bovine brain membranes
|
Bos taurus
|
0.9
nM
|
|
Journal : J. Med. Chem.
Title : N'-Phenylindol-3-ylglyoxylohydrazide derivatives: synthesis, structure-activity relationships, molecular modeling studies, and pharmacological action on brain benzodiazepine receptors.
Year : 1998
Volume : 41
Issue : 20
First Page : 3821
Last Page : 3830
Authors : Da Settimo A, Primofiore G, Da Settimo F, Marini AM, Novellino E, Greco G, Gesi M, Martini C, Giannaccini G, Lucacchini A.
Abstract : A series of N'-phenylindol-3-ylglyoxylohydrazides, isosters of the N-benzylindol-3-ylglyoxylamide derivatives previously described by us, were synthesized and tested for their ability to displace [3H]Ro 15-1788 from bovine brain membranes. These compounds were designed with the aim of obtaining products which could exert an in vivo activity, thanks to a higher hydrosolubility and consequently a better bioavailability. Affinity was restricted to the derivatives unsubstituted in the 5 position of the indole nucleus (1, 6, 9, 12, 15, 18, 23, and 26), with Ki values ranging from 510 to 11 nM. The most active compounds (6, 9, 23, and 29) proved to be effective in antagonizing pentylenetetrazole-induced seizures. Molecular modeling studies were performed to rationalize the lack of affinity of hydrazides with a chloro or a nitro group in the 5 position of the indole nucleus. It was hypothesized that the conformational preference of the hydrazide side chain, characterized by a gauche disposition of lone pairs and substituents about the N-N bond, prevents all hydrazides from binding to the receptor similarly to other classes of indole analogues previously investigated. The potency of 5-H hydrazides was attributed to a binding mode which is not feasible for 5-Cl and 5-NO2 counterparts. This theoretical model of ligand-receptor interaction permitted a more stringent interpretation of structure-affinity relationships of hydrazides and of recently described benzylamide derivatives (Da Settimo et al. J. Med. Chem. 1996, 39, 5083-5091).
|
Binding affinity towards Benzodiazepine receptor from bovine brain membrane using [3H]Ro-151788 as radioligand
|
Bos taurus
|
0.9
nM
|
|
Journal : J. Med. Chem.
Title : Benzodiazepine receptor ligands. 7. Synthesis and pharmacological evaluation of new 3-esters of the 8-chloropyrazolo[5,1-c][1,2,4]benzotriazine 5-oxide. 3-(2-Thienylmethoxycarbonyl) derivative: an anxioselective agent in rodents.
Year : 2002
Volume : 45
Issue : 26
First Page : 5710
Last Page : 5720
Authors : Costanzo A, Guerrini G, Ciciani G, Bruni F, Costagli C, Selleri S, Besnard F, Costa B, Martini C, Malmberg-Aiello P.
Abstract : The synthesis and binding study of new 8-chloropyrazolo[5,1-c][1,2,4]benzotriazine 5-oxide 3-ester compounds are reported. A pharmacological evaluation of the high-affinity ligands 1-4 belonging to the 3-heteroarylester series is made. The 3-(2-thienylmethoxycarbonyl) derivative 4 stands out from the other heteroarylesters and is found, using nine different behavioral methods, to be a functionally selective ligand in vivo: it shows anxiolytic-like activity in the conflict models (light-dark box and plus maze test) similarly to diazepam, without any sedative and amnesic properties or interference from alcohol.
|
Affinity to displace [3H]flunitrazepam from Benzodiazepine receptor in bovine brain membrane
|
None
|
0.5
nM
|
|
Journal : J. Med. Chem.
Title : Tricyclic heteroaromatic systems. [1]benzopyranopyrrol-4-ones and [1]benzopyrano-1,2,3-triazol-4-ones as benzodiazepine receptor ligands. Synthesis and structure-activity relationships.
Year : 1990
Volume : 33
Issue : 9
First Page : 2646
Last Page : 2651
Authors : Colotta V, Cecchi L, Melani F, Filacchioni G, Martini C, Giannaccini G, Lucacchini A.
Abstract : The synthesis, ability to displace [3H]flunitrazepam binding from bovine brain membranes, and GABA ratio of some [1]benzopyranopyrroles 1a-i and [1]benzopyrano-1,2,3-triazoles 2a,b are reported. The GABA ratios of some previously synthesized pyrazoloquinolines A and [1]benzopyranopyrazoles C are also presented in order to draw some structure-activity relationships among our benzodiazepine receptor ligands. 1,3-Diarylpyrrole derivatives 1a-h show similar affinity and efficacy to that of diazepam, while the 1-aryltriazoles 2a,b have no receptor affinity. Comparison of the latter results with those on previously reported compounds suggests that there are several hydrophobic regions on the benzodiazepine recognition site whose occupation gives rise to different affinity and efficacy.
|
In vitro inhibition of [3H]flunitrazepam binding to GABA-A benzodiazepine receptor of bovine cerebral cortical membranes at 10 uM
|
Bos taurus
|
0.38
nM
|
|
Journal : J. Med. Chem.
Title : Benzodiazepine receptor affinity and interaction of some N-(indol-3-ylglyoxylyl)amine derivatives.
Year : 1992
Volume : 35
Issue : 12
First Page : 2214
Last Page : 2220
Authors : Bianucci AM, Da Settimo A, Da Settimo F, Primofiore G, Martini C, Giannaccini G, Lucacchini A.
Abstract : Several derivatives, in which tryptamine, tyramine, and dopamine moieties are linked to the indole nucleus by an oxalyl bridge, were tested for their ability to displace the specific binding of [3H]flunitrazepam from bovine brain membranes. GABA ratio and in vivo tests for the most potent compounds showed they behave as inverse agonists at the benzodiazepine receptor (BzR). To better define the structure-activity relationship (SAR) of this kind of ligand, several phenylethylamine derivatives were synthesized to evaluate their affinity to BzR. Some of these derivatives (17, 21, 24, 26, and 30) were found to exhibit high affinity (Ki = 0.51-0.085 microM) for BzR and possessed a partial agonist activity, although their chemical structure is closely related to tryptamine 2-6, tyramine 7-11, and dopamine 12-16 derivatives. A different interaction of these ligands to the receptor site is hypothesized. Moreover, all the prepared 1-methyl derivatives exhibited very low binding affinity to BzR.
|
Inhibition of [3H]flumazenil binding to GABA-A benzodiazepine receptor of bovine brain membranes
|
Bos taurus
|
0.9
nM
|
|
Journal : J. Med. Chem.
Title : Novel N-(arylalkyl)indol-3-ylglyoxylylamides targeted as ligands of the benzodiazepine receptor: synthesis, biological evaluation, and molecular modeling analysis of the structure-activity relationships.
Year : 2001
Volume : 44
Issue : 14
First Page : 2286
Last Page : 2297
Authors : Primofiore G, Settimo FD, Taliani S, Marini AM, Novellino E, Greco G, Lavecchia A, Besnard F, Trincavelli L, Costa B, Martini C.
Abstract : A series of N-(arylalkyl)indol-3-ylglyoxylylamides (4-8) was synthesized as ligands of the benzodiazepine receptor (BzR) and tested for their ability to displace [(3)H]flumazenil from bovine brain membranes. The new compounds, bearing a branched (4) or a geometrically constrained benzyl/phenylethyl amide side chain (5-8), represent the continuation of our research on N-benzylindol-3-ylglyoxylylamides 1 (Da Settimo et al., 1996), N'-phenylindol-3-ylglyoxylohydrazides 2 (Da Settimo et al., 1998), and N-(indol-3-ylglyoxylyl)alanine derivatives 3 (Primofiore et al., 1989). A few indoles belonging to the previously investigated benzylamides 1 and phenylhydrazides 2 were synthesized and tested to enrich the SARs in these two series. The affinities and the GABA ratios of selected compounds for clonal mammalian alpha(1)beta(2)gamma(2), alpha(3)beta(2)gamma(2), and alpha(5)beta(3)gamma(2) BzR subtypes were also determined. It was hypothesized that the reduced flexibility of indoles 4-8 would both facilitate the mapping of the BzR binding cleft and increase the chances of conferring selectivity for the considered receptor subtypes. In the series of indoles 4, the introduction of a methyl group on the benzylic carbon with the R configuration improved affinity of the 5-substituted (5-Cl and 5-NO(2)) derivatives, whereas it was detrimental for their 5-unsubtituted (5-H) counterparts. All S enantiomers were less potent than the R ones. Replacement of the methyl with hydrophilic substituents on the benzylic carbon lowered affinity. The isoindolinylamide side chain was tolerated if the 5-position was unsubstituted (K(i) of 5a = 123 nM), otherwise affinity was abolished (5b, c). All the 2-indanylamides 6 and (S)-1-indanylamides 8 were devoid of any appreciable affinity. The 5-Cl and 5-NO(2) (R)-1-indanylamides 7b (K(i) 80 nM) and 7c (K(i) 28 nM) were the most potent among the indoles 5-8 geometrically constrained about the side chain. The 5-H (R)-1-indanylamide 7a displayed a lower affinity (K(i) 675 nM). The SARs developed from the new compounds, together with those collected from our previous studies, confirmed the hypothesis of different binding modes for 5-substituted and 5-unsubstituted indoles, suggesting that the shape of the lipophilic pocket L(1) (notation in accordance with Cook's BzR topological model) is asymmetric and highlighted the stereoelectronic and conformational properties of the amide side chain required for high potency. Several of the new indoles showed selectivity for the alpha(1)beta(2)gamma(2) subtype compared with the alpha(3)beta(2)gamma(2) and alpha(5)beta(3)gamma(2) subtypes (e.g.: 4t and 7c bind to these three BzR isoforms with K(i) values of 14 nM, 283 nM, 239 nM, and 9 nM, 1960 nM, 95 nM, respectively). The GABA ratios close to unity exhibited by all the tested compounds on each BzR subtype were predictive of an efficacy profile typical of antagonists.
|
Displacement of [3H]- Ro.15-1788 from GABA-A central Benzodiazepine receptor (BzR) of Bovine cerebral cortex membrane
|
Bos taurus
|
0.09
nM
|
|
Journal : J. Med. Chem.
Title : 3-Aryl-[1,2,4]triazino[4,3-a]benzimidazol-4(10H)-ones: tricyclic heteroaromatic derivatives as a new class of benzodiazepine receptor ligands.
Year : 2000
Volume : 43
Issue : 1
First Page : 96
Last Page : 102
Authors : Primofiore G, Da Settimo F, Taliani S, Marini AM, La Motta C, Novellino E, Greco G, Gesi M, Trincavelli L, Martini C.
Abstract : A series of 3-substituted [1,2,4]triazino[4,3-c]benzimidazoles V were prepared and tested at the central benzodiazepine receptor (BzR). These compounds were designed as rigid analogues of the previously described N-benzylindolylglyoxylylamide derivatives IV. The title compounds V showed an affinity which depended directly on the presence of the N(10)-H group and an aromatic ring at position 3. Some of them elicited a 2- or 3-fold higher affinity with respect to that of the indolylglyoxylylamide derivatives IV (R = H). The GABA ratio and [(35)S]-tert-butylcyclophosphorothionate binding data revealed an efficacy profile of partial inverse agonists/antagonists for compounds 1c,e,f,j,k, and of a partial agonist for 2c. This last compound proved to be effective in antagonizing pentylenetetrazole-induced seizures in mice. Attempts were made to interpret the structure-affinity relationships of compounds V in the light of possible tautomeric equilibria involving the ligands.
|
Binding affinity for human recombinant gamma-aminobutyric-acid (GABA) A receptor alpha-6-beta-3-gamma-2
|
None
|
148.0
nM
|
|
Journal : J. Med. Chem.
Title : Pharmacophore/receptor models for GABA(A)/BzR subtypes (alpha1beta3gamma2, alpha5beta3gamma2, and alpha6beta3gamma2) via a comprehensive ligand-mapping approach.
Year : 2000
Volume : 43
Issue : 1
First Page : 71
Last Page : 95
Authors : Huang Q, He X, Ma C, Liu R, Yu S, Dayer CA, Wenger GR, McKernan R, Cook JM.
Abstract : Pharmacophore/receptor models for three recombinant GABA(A)/BzR subtypes (alpha1beta3gamma2, alpha5beta3gamma2, and alpha6beta3gamma2) have been established via an SAR ligand-mapping approach. This study was based on the affinities of 151 BzR ligands at five distinct (alpha1-3,5,6beta3gamma2) recombinant GABA(A)/BzR receptor subtypes from at least nine different structural families. Examination of the included volumes of the alpha1-, alpha5-, and alpha6-containing subtypes indicated that region L(2) for the alpha5-containing subtype appeared to be larger in size than the analogous region of the other receptor subtypes. Region L(Di), in contrast, appeared to be larger in the alpha1 subtype than in the other two subtypes. Moreover, region L(3) in the alpha6 subtype is either very small or nonexistent in this diazepam-insensitive subtype (see Figure 16 for details) as compared to the other subtypes. Use of the pharmacophore/receptor models for these subtypes has resulted in the design of novel BzR ligands (see 27) selective for the alpha5beta3gamma2 receptor subtype. alpha5-Selective ligand 27 when injected directly into the hippocampus did enhance memory in one paradigm (Bailey et al., unpublished observations); however, systemic administration of either 9 or 27 into animals did not provide an observable enhancement. This result is in complete agreement with the observation of Liu (1996). It has been shown (Liu, 1996; Wisden et al., 1992) that in the central nervous system of the rat (as well as monkeys and pigeons) there are several native subtypes of the GABA(A) receptor which exhibit different functions, regional distributions, and neuronal locations. Although 27 binds more potently at alpha5beta3gamma2 receptor subtypes and is clearly an inverse agonist (Liu et al., 1996; Liu, 1996), it is possible that this ligand acts as an agonist at one or more subtypes. Liu (1996) clearly showed that a number of imidazobenzodiazepines were negative modulators at one subtype and agonists at another. Therefore, selectivity for a particular subtype at this point is not sufficient to rule out some physiological effect at other GABA(A)/BzR subtypes. The inability of 27 to potentiate memory when given systemically is again in support of this hypothesis, especially since alpha1beta2gamma2 subtypes are distributed throughout the brain (Wisden et al., 1992). A drug delivered systemically is far more likely to interact with all subtypes than one delivered to a specific brain region. This observation (systemic vs intrahippocampal) provides further support for the design of more subtype-specific ligands at the BzR to accurately define their pharmacology, one key to the design of new drugs with fewer side effects.
|
Binding affinity against Gamma-aminobutyric acid A receptor alpha-6-beta-3-gamma-2
|
None
|
148.0
nM
|
|
Journal : J. Med. Chem.
Title : Predictive models for GABAA/benzodiazepine receptor subtypes: studies of quantitative structure-activity relationships for imidazobenzodiazepines at five recombinant GABAA/benzodiazepine receptor subtypes [alphaxbeta3gamma2 (x = 1-3, 5, and 6)] via comparative molecular field analysis.
Year : 1998
Volume : 41
Issue : 21
First Page : 4130
Last Page : 4142
Authors : Huang Q, Liu R, Zhang P, He X, McKernan R, Gan T, Bennett DW, Cook JM.
Abstract : Affinities of a series of substituted imidazobenzodiazepines at recombinant alpha1beta3gamma2, alpha2beta3gamma2, alpha3beta3gamma2, alpha5beta3gamma2, and alpha6beta3gamma2 GABAA/benzodiazepine receptor subtypes are reported. Many of these ligands displayed high affinities (low-nanomolar to subnanomolar scale) at all five receptor subtypes. Furthermore, a number of imidazobenzodiazepines exhibited relatively good selectivity at the alpha5-containing receptor isoform. For example, ligand 27 (RY-023) demonstrated a 55-fold higher selectivity at alpha5beta3gamma2 isoforms in comparison to other receptor subtypes. The affinity ratio of alpha1 (the most prevalent subtype in the brain) to alpha5 of this series of ligands ranged from 60- to 75-fold for the most selective ligands. Studies of quantitative structure-activity relationships (QSAR) by means of comparative molecular field analysis (CoMFA) were carried out. As a result, examination of CoMFA models for all five receptor subtypes demonstrated their predictability for affinities of imidazobenzodiazepines at the five receptor subtypes. Regions of molecular fields which would favor or disfavor the binding affinity of a ligand at a specific receptor subtype were examined via CoMFA for alpha1, alpha2, alpha3, alpha5, and alpha6 subtypes. A CoMFA regression analysis was applied to predict the ratio of Ki alpha1/Ki alpha5, an index for the selectivity of a ligand at the alpha5 subtype. All of the CoMFA models offered good cross-validated correlations for the ligands in the test set as well as the ratios of Ki alpha1/Ki alpha5, which demonstrated their potential for prediction.
|
Binding affinity against Diazepam insensitive (DI) Gamma-aminobutyric acid A receptor
|
Rattus norvegicus
|
58.0
nM
|
|
Journal : J. Med. Chem.
Title : Synthesis of novel imidazobenzodiazepines as probes of the pharmacophore for "diazepam-insensitive" GABAA receptors.
Year : 1995
Volume : 38
Issue : 10
First Page : 1679
Last Page : 1688
Authors : Zhang P, Zhang W, Liu R, Harris B, Skolnick P, Cook JM.
Abstract : The syntheses of a series of novel imidazobenzodiazepines and their affinities for diazepam sensitive (DS) and diazepam insensitive (DI) GABAA receptors are described. Imidazobenzodiazepines belong to one of the very few chemical families which exhibit high to moderate potency for DI GABAA receptors. Although imidazobenzodiazepines such as Ro 15-4513, 20, are the most potent DI GABAA receptor ligands described to date, their selectivity for DI versus DS GABAA receptors is only marginal. Previous structure-activity relationship (SAR) studies of imidazobenzodiazepines have indicated that the 3- and 8-positions are critical for high-affinity binding to DI GABAA receptors (J. Med. Chem. 1993, 36, 479-490. J. Med. Chem. 1993, 36, 1001-1006. J. Med. Chem. 1993, 36, 1820-1830). In order to determine why the ester function is critical to high affinity at the DI site, we have synthesized several derivatives which have substituents other than an ester at the C(3) position including 3-alkyl-, 3-alkylketo-, 3-alkyl ether, and 3-dialkylamino-substituted imidazobenzodiazepines. The SAR analysis of these compounds when combined with that of several pyrazoloquinolinones indicates that interactions at H1 and L1 as well as interactions at H2 anti to the imidazole N(2) and at a lipophilic pocket (labeled LDi) about the 3-position are required in order for imidazobenzodiazepines to exhibit selectivity and high affinity for DI GABAA receptors. Furthermore, the imidazobenzodiazepines substituted with an electron-donating group (alkoxy function) at position 8 revealed that the change of the substituent at C(8) from an electron-withdrawing to a donating function did not substantially alter either ligand affinity or selectivity for DI GABAA receptors. Thus, a pharmacophore is proposed for DI GABAA receptor ligands, which is characterized by the requirement of a lipophilic pocket LDi about the C(3) position of imidazobenzodiazepines. Using this model, two pyrazoloquinolinone derivatives were designed and synthesized. Their affinities and selectivities for DI GABAA receptors are consistent with those predicted by the DI GABAA receptor pharmacophore. In addition, examination of the in vitro binding data of 3-alkyl ether analogs confirms that the anti conformation of the ester group at the C(3) position of imidazobenzodiazepines (Ro15-4513, 20 series) is preferred at both DI and DS GABAA receptors. This constitutes the first evidence (other than molecular modeling) to support the auxillary involvement of H2 at the DI site and is important with regard to the synthesis of other DI GABAA receptor selective ligands in the future.(ABSTRACT TRUNCATED AT 400 WORDS)
|
Binding affinity against Diazepam sensitive (DS) Gamma-aminobutyric acid A receptor in rat cerebellum.
|
Rattus norvegicus
|
0.8
nM
|
|
Journal : J. Med. Chem.
Title : Synthesis of novel imidazobenzodiazepines as probes of the pharmacophore for "diazepam-insensitive" GABAA receptors.
Year : 1995
Volume : 38
Issue : 10
First Page : 1679
Last Page : 1688
Authors : Zhang P, Zhang W, Liu R, Harris B, Skolnick P, Cook JM.
Abstract : The syntheses of a series of novel imidazobenzodiazepines and their affinities for diazepam sensitive (DS) and diazepam insensitive (DI) GABAA receptors are described. Imidazobenzodiazepines belong to one of the very few chemical families which exhibit high to moderate potency for DI GABAA receptors. Although imidazobenzodiazepines such as Ro 15-4513, 20, are the most potent DI GABAA receptor ligands described to date, their selectivity for DI versus DS GABAA receptors is only marginal. Previous structure-activity relationship (SAR) studies of imidazobenzodiazepines have indicated that the 3- and 8-positions are critical for high-affinity binding to DI GABAA receptors (J. Med. Chem. 1993, 36, 479-490. J. Med. Chem. 1993, 36, 1001-1006. J. Med. Chem. 1993, 36, 1820-1830). In order to determine why the ester function is critical to high affinity at the DI site, we have synthesized several derivatives which have substituents other than an ester at the C(3) position including 3-alkyl-, 3-alkylketo-, 3-alkyl ether, and 3-dialkylamino-substituted imidazobenzodiazepines. The SAR analysis of these compounds when combined with that of several pyrazoloquinolinones indicates that interactions at H1 and L1 as well as interactions at H2 anti to the imidazole N(2) and at a lipophilic pocket (labeled LDi) about the 3-position are required in order for imidazobenzodiazepines to exhibit selectivity and high affinity for DI GABAA receptors. Furthermore, the imidazobenzodiazepines substituted with an electron-donating group (alkoxy function) at position 8 revealed that the change of the substituent at C(8) from an electron-withdrawing to a donating function did not substantially alter either ligand affinity or selectivity for DI GABAA receptors. Thus, a pharmacophore is proposed for DI GABAA receptor ligands, which is characterized by the requirement of a lipophilic pocket LDi about the C(3) position of imidazobenzodiazepines. Using this model, two pyrazoloquinolinone derivatives were designed and synthesized. Their affinities and selectivities for DI GABAA receptors are consistent with those predicted by the DI GABAA receptor pharmacophore. In addition, examination of the in vitro binding data of 3-alkyl ether analogs confirms that the anti conformation of the ester group at the C(3) position of imidazobenzodiazepines (Ro15-4513, 20 series) is preferred at both DI and DS GABAA receptors. This constitutes the first evidence (other than molecular modeling) to support the auxillary involvement of H2 at the DI site and is important with regard to the synthesis of other DI GABAA receptor selective ligands in the future.(ABSTRACT TRUNCATED AT 400 WORDS)
|
Binding affinity to rat chimeric GABA-A receptor C6, alpha1-alpha6 chimeric subunit co-expressed with beta-2 gamma2 subunits in HEK293 cells
|
Rattus norvegicus
|
0.6
nM
|
|
Journal : J. Med. Chem.
Title : Four amino acid exchanges convert a diazepam-insensitive, inverse agonist-preferring GABAA receptor into a diazepam-preferring GABAA receptor.
Year : 1994
Volume : 37
Issue : 26
First Page : 4576
Last Page : 4580
Authors : Wieland HA, Lüddens H.
Abstract : Benzodiazepines (BZ) exert their effects through GABAA receptors, which belong to the superfamily of ligand-gated ion channels. Coexpression of recombinant alpha, beta, and gamma subunits in a cell culture system mimics the BZ binding sites. The alpha variants largely determine the nature of the BZ binding site in such alpha i beta j gamma k heteromultimers (i = 1-6; j = 1-3; k = 1-3). Notably, the alpha 1 and alpha 6 variants confer high and low affinity for BZ agonists to the resulting receptor subtype, respectively. Glycine/glutamate and histidine/arginine positions in the alpha subunits of alpha x beta 2 gamma 2 receptors are involved in BZ I versus BZ II type selectivity. We now identify four amino acids in alpha 6 which together increase the affinity of the mutant alpha x beta 2 gamma 2 receptor for classical BZ receptor agonists above the level seen for any wild-type GABAA/BZ receptor. The most pronounced effect was due to an isoleucine to valine exchange. It simultaneously decreased the affinity for the BZ partial inverse agonist Ro 15-4513 20-fold and increased the affinity for diazepam 4-fold. The four amino acid residues stretch over most part of the N-terminal extracellular domain of the alpha subunit, suggesting that amino acids distant in the primary sequence form the BZ binding pocket.
|
Binding affinity for human recombinant gamma-aminobutyric-acid (GABA) A receptor alpha-1-beta-3-gamma-2
|
None
|
0.8
nM
|
|
Journal : J. Med. Chem.
Title : Pharmacophore/receptor models for GABA(A)/BzR subtypes (alpha1beta3gamma2, alpha5beta3gamma2, and alpha6beta3gamma2) via a comprehensive ligand-mapping approach.
Year : 2000
Volume : 43
Issue : 1
First Page : 71
Last Page : 95
Authors : Huang Q, He X, Ma C, Liu R, Yu S, Dayer CA, Wenger GR, McKernan R, Cook JM.
Abstract : Pharmacophore/receptor models for three recombinant GABA(A)/BzR subtypes (alpha1beta3gamma2, alpha5beta3gamma2, and alpha6beta3gamma2) have been established via an SAR ligand-mapping approach. This study was based on the affinities of 151 BzR ligands at five distinct (alpha1-3,5,6beta3gamma2) recombinant GABA(A)/BzR receptor subtypes from at least nine different structural families. Examination of the included volumes of the alpha1-, alpha5-, and alpha6-containing subtypes indicated that region L(2) for the alpha5-containing subtype appeared to be larger in size than the analogous region of the other receptor subtypes. Region L(Di), in contrast, appeared to be larger in the alpha1 subtype than in the other two subtypes. Moreover, region L(3) in the alpha6 subtype is either very small or nonexistent in this diazepam-insensitive subtype (see Figure 16 for details) as compared to the other subtypes. Use of the pharmacophore/receptor models for these subtypes has resulted in the design of novel BzR ligands (see 27) selective for the alpha5beta3gamma2 receptor subtype. alpha5-Selective ligand 27 when injected directly into the hippocampus did enhance memory in one paradigm (Bailey et al., unpublished observations); however, systemic administration of either 9 or 27 into animals did not provide an observable enhancement. This result is in complete agreement with the observation of Liu (1996). It has been shown (Liu, 1996; Wisden et al., 1992) that in the central nervous system of the rat (as well as monkeys and pigeons) there are several native subtypes of the GABA(A) receptor which exhibit different functions, regional distributions, and neuronal locations. Although 27 binds more potently at alpha5beta3gamma2 receptor subtypes and is clearly an inverse agonist (Liu et al., 1996; Liu, 1996), it is possible that this ligand acts as an agonist at one or more subtypes. Liu (1996) clearly showed that a number of imidazobenzodiazepines were negative modulators at one subtype and agonists at another. Therefore, selectivity for a particular subtype at this point is not sufficient to rule out some physiological effect at other GABA(A)/BzR subtypes. The inability of 27 to potentiate memory when given systemically is again in support of this hypothesis, especially since alpha1beta2gamma2 subtypes are distributed throughout the brain (Wisden et al., 1992). A drug delivered systemically is far more likely to interact with all subtypes than one delivered to a specific brain region. This observation (systemic vs intrahippocampal) provides further support for the design of more subtype-specific ligands at the BzR to accurately define their pharmacology, one key to the design of new drugs with fewer side effects.
|
Binding affinity to human recombinant gamma-aminobutyric-acid (GABA) A receptor alpha-2-beta-3-gamma-2
|
None
|
0.9
nM
|
|
Journal : J. Med. Chem.
Title : Pharmacophore/receptor models for GABA(A)/BzR subtypes (alpha1beta3gamma2, alpha5beta3gamma2, and alpha6beta3gamma2) via a comprehensive ligand-mapping approach.
Year : 2000
Volume : 43
Issue : 1
First Page : 71
Last Page : 95
Authors : Huang Q, He X, Ma C, Liu R, Yu S, Dayer CA, Wenger GR, McKernan R, Cook JM.
Abstract : Pharmacophore/receptor models for three recombinant GABA(A)/BzR subtypes (alpha1beta3gamma2, alpha5beta3gamma2, and alpha6beta3gamma2) have been established via an SAR ligand-mapping approach. This study was based on the affinities of 151 BzR ligands at five distinct (alpha1-3,5,6beta3gamma2) recombinant GABA(A)/BzR receptor subtypes from at least nine different structural families. Examination of the included volumes of the alpha1-, alpha5-, and alpha6-containing subtypes indicated that region L(2) for the alpha5-containing subtype appeared to be larger in size than the analogous region of the other receptor subtypes. Region L(Di), in contrast, appeared to be larger in the alpha1 subtype than in the other two subtypes. Moreover, region L(3) in the alpha6 subtype is either very small or nonexistent in this diazepam-insensitive subtype (see Figure 16 for details) as compared to the other subtypes. Use of the pharmacophore/receptor models for these subtypes has resulted in the design of novel BzR ligands (see 27) selective for the alpha5beta3gamma2 receptor subtype. alpha5-Selective ligand 27 when injected directly into the hippocampus did enhance memory in one paradigm (Bailey et al., unpublished observations); however, systemic administration of either 9 or 27 into animals did not provide an observable enhancement. This result is in complete agreement with the observation of Liu (1996). It has been shown (Liu, 1996; Wisden et al., 1992) that in the central nervous system of the rat (as well as monkeys and pigeons) there are several native subtypes of the GABA(A) receptor which exhibit different functions, regional distributions, and neuronal locations. Although 27 binds more potently at alpha5beta3gamma2 receptor subtypes and is clearly an inverse agonist (Liu et al., 1996; Liu, 1996), it is possible that this ligand acts as an agonist at one or more subtypes. Liu (1996) clearly showed that a number of imidazobenzodiazepines were negative modulators at one subtype and agonists at another. Therefore, selectivity for a particular subtype at this point is not sufficient to rule out some physiological effect at other GABA(A)/BzR subtypes. The inability of 27 to potentiate memory when given systemically is again in support of this hypothesis, especially since alpha1beta2gamma2 subtypes are distributed throughout the brain (Wisden et al., 1992). A drug delivered systemically is far more likely to interact with all subtypes than one delivered to a specific brain region. This observation (systemic vs intrahippocampal) provides further support for the design of more subtype-specific ligands at the BzR to accurately define their pharmacology, one key to the design of new drugs with fewer side effects.
|
Binding affinity for human recombinant gamma-aminobutyric-acid (GABA) A receptor alpha-3-beta-3-gamma-2
|
None
|
1.1
nM
|
|
Journal : J. Med. Chem.
Title : Pharmacophore/receptor models for GABA(A)/BzR subtypes (alpha1beta3gamma2, alpha5beta3gamma2, and alpha6beta3gamma2) via a comprehensive ligand-mapping approach.
Year : 2000
Volume : 43
Issue : 1
First Page : 71
Last Page : 95
Authors : Huang Q, He X, Ma C, Liu R, Yu S, Dayer CA, Wenger GR, McKernan R, Cook JM.
Abstract : Pharmacophore/receptor models for three recombinant GABA(A)/BzR subtypes (alpha1beta3gamma2, alpha5beta3gamma2, and alpha6beta3gamma2) have been established via an SAR ligand-mapping approach. This study was based on the affinities of 151 BzR ligands at five distinct (alpha1-3,5,6beta3gamma2) recombinant GABA(A)/BzR receptor subtypes from at least nine different structural families. Examination of the included volumes of the alpha1-, alpha5-, and alpha6-containing subtypes indicated that region L(2) for the alpha5-containing subtype appeared to be larger in size than the analogous region of the other receptor subtypes. Region L(Di), in contrast, appeared to be larger in the alpha1 subtype than in the other two subtypes. Moreover, region L(3) in the alpha6 subtype is either very small or nonexistent in this diazepam-insensitive subtype (see Figure 16 for details) as compared to the other subtypes. Use of the pharmacophore/receptor models for these subtypes has resulted in the design of novel BzR ligands (see 27) selective for the alpha5beta3gamma2 receptor subtype. alpha5-Selective ligand 27 when injected directly into the hippocampus did enhance memory in one paradigm (Bailey et al., unpublished observations); however, systemic administration of either 9 or 27 into animals did not provide an observable enhancement. This result is in complete agreement with the observation of Liu (1996). It has been shown (Liu, 1996; Wisden et al., 1992) that in the central nervous system of the rat (as well as monkeys and pigeons) there are several native subtypes of the GABA(A) receptor which exhibit different functions, regional distributions, and neuronal locations. Although 27 binds more potently at alpha5beta3gamma2 receptor subtypes and is clearly an inverse agonist (Liu et al., 1996; Liu, 1996), it is possible that this ligand acts as an agonist at one or more subtypes. Liu (1996) clearly showed that a number of imidazobenzodiazepines were negative modulators at one subtype and agonists at another. Therefore, selectivity for a particular subtype at this point is not sufficient to rule out some physiological effect at other GABA(A)/BzR subtypes. The inability of 27 to potentiate memory when given systemically is again in support of this hypothesis, especially since alpha1beta2gamma2 subtypes are distributed throughout the brain (Wisden et al., 1992). A drug delivered systemically is far more likely to interact with all subtypes than one delivered to a specific brain region. This observation (systemic vs intrahippocampal) provides further support for the design of more subtype-specific ligands at the BzR to accurately define their pharmacology, one key to the design of new drugs with fewer side effects.
|
Binding affinity for human recombinant gamma-aminobutyric-acid (GABA) A receptor alpha-5-beta-3-gamma-2
|
None
|
0.6
nM
|
|
Journal : J. Med. Chem.
Title : Pharmacophore/receptor models for GABA(A)/BzR subtypes (alpha1beta3gamma2, alpha5beta3gamma2, and alpha6beta3gamma2) via a comprehensive ligand-mapping approach.
Year : 2000
Volume : 43
Issue : 1
First Page : 71
Last Page : 95
Authors : Huang Q, He X, Ma C, Liu R, Yu S, Dayer CA, Wenger GR, McKernan R, Cook JM.
Abstract : Pharmacophore/receptor models for three recombinant GABA(A)/BzR subtypes (alpha1beta3gamma2, alpha5beta3gamma2, and alpha6beta3gamma2) have been established via an SAR ligand-mapping approach. This study was based on the affinities of 151 BzR ligands at five distinct (alpha1-3,5,6beta3gamma2) recombinant GABA(A)/BzR receptor subtypes from at least nine different structural families. Examination of the included volumes of the alpha1-, alpha5-, and alpha6-containing subtypes indicated that region L(2) for the alpha5-containing subtype appeared to be larger in size than the analogous region of the other receptor subtypes. Region L(Di), in contrast, appeared to be larger in the alpha1 subtype than in the other two subtypes. Moreover, region L(3) in the alpha6 subtype is either very small or nonexistent in this diazepam-insensitive subtype (see Figure 16 for details) as compared to the other subtypes. Use of the pharmacophore/receptor models for these subtypes has resulted in the design of novel BzR ligands (see 27) selective for the alpha5beta3gamma2 receptor subtype. alpha5-Selective ligand 27 when injected directly into the hippocampus did enhance memory in one paradigm (Bailey et al., unpublished observations); however, systemic administration of either 9 or 27 into animals did not provide an observable enhancement. This result is in complete agreement with the observation of Liu (1996). It has been shown (Liu, 1996; Wisden et al., 1992) that in the central nervous system of the rat (as well as monkeys and pigeons) there are several native subtypes of the GABA(A) receptor which exhibit different functions, regional distributions, and neuronal locations. Although 27 binds more potently at alpha5beta3gamma2 receptor subtypes and is clearly an inverse agonist (Liu et al., 1996; Liu, 1996), it is possible that this ligand acts as an agonist at one or more subtypes. Liu (1996) clearly showed that a number of imidazobenzodiazepines were negative modulators at one subtype and agonists at another. Therefore, selectivity for a particular subtype at this point is not sufficient to rule out some physiological effect at other GABA(A)/BzR subtypes. The inability of 27 to potentiate memory when given systemically is again in support of this hypothesis, especially since alpha1beta2gamma2 subtypes are distributed throughout the brain (Wisden et al., 1992). A drug delivered systemically is far more likely to interact with all subtypes than one delivered to a specific brain region. This observation (systemic vs intrahippocampal) provides further support for the design of more subtype-specific ligands at the BzR to accurately define their pharmacology, one key to the design of new drugs with fewer side effects.
|
Binding affinity for Gamma-aminobutyric acid A receptor alpha-5-beta-3-gamma-2
|
None
|
0.6
nM
|
|
Journal : J. Med. Chem.
Title : Predictive models for GABAA/benzodiazepine receptor subtypes: studies of quantitative structure-activity relationships for imidazobenzodiazepines at five recombinant GABAA/benzodiazepine receptor subtypes [alphaxbeta3gamma2 (x = 1-3, 5, and 6)] via comparative molecular field analysis.
Year : 1998
Volume : 41
Issue : 21
First Page : 4130
Last Page : 4142
Authors : Huang Q, Liu R, Zhang P, He X, McKernan R, Gan T, Bennett DW, Cook JM.
Abstract : Affinities of a series of substituted imidazobenzodiazepines at recombinant alpha1beta3gamma2, alpha2beta3gamma2, alpha3beta3gamma2, alpha5beta3gamma2, and alpha6beta3gamma2 GABAA/benzodiazepine receptor subtypes are reported. Many of these ligands displayed high affinities (low-nanomolar to subnanomolar scale) at all five receptor subtypes. Furthermore, a number of imidazobenzodiazepines exhibited relatively good selectivity at the alpha5-containing receptor isoform. For example, ligand 27 (RY-023) demonstrated a 55-fold higher selectivity at alpha5beta3gamma2 isoforms in comparison to other receptor subtypes. The affinity ratio of alpha1 (the most prevalent subtype in the brain) to alpha5 of this series of ligands ranged from 60- to 75-fold for the most selective ligands. Studies of quantitative structure-activity relationships (QSAR) by means of comparative molecular field analysis (CoMFA) were carried out. As a result, examination of CoMFA models for all five receptor subtypes demonstrated their predictability for affinities of imidazobenzodiazepines at the five receptor subtypes. Regions of molecular fields which would favor or disfavor the binding affinity of a ligand at a specific receptor subtype were examined via CoMFA for alpha1, alpha2, alpha3, alpha5, and alpha6 subtypes. A CoMFA regression analysis was applied to predict the ratio of Ki alpha1/Ki alpha5, an index for the selectivity of a ligand at the alpha5 subtype. All of the CoMFA models offered good cross-validated correlations for the ligands in the test set as well as the ratios of Ki alpha1/Ki alpha5, which demonstrated their potential for prediction.
|
Inhibition of binding of Batrachotoxinin [3H]BTX-B to high affinity sites on voltage dependent sodium channels in a vesicular preparation from guinea pig cerebral cortex at 10 uM
|
Cavia porcellus
|
6.9
%
|
|
Journal : J. Med. Chem.
Title : [3H]Batrachotoxinin A 20 alpha-benzoate binding to voltage-sensitive sodium channels: a rapid and quantitative assay for local anesthetic activity in a variety of drugs.
Year : 1985
Volume : 28
Issue : 3
First Page : 381
Last Page : 388
Authors : McNeal ET, Lewandowski GA, Daly JW, Creveling CR.
Abstract : [3H]Batrachotoxinin A benzoate ( [3H]BTX-B) binds with high affinity to sites on voltage-dependent sodium channels in a vesicular preparation from guinea pig cerebral cortex. In this preparation, local anesthetics competitively antagonize the binding of [3H]BTX-B. The potencies of some 40 classical local anesthetics and a variety of catecholamine, histamine, serotonin, adenosine, GABA, glycine, acetylcholine, and calcium antagonists, tranquilizers, antidepressants, barbiturates, anticonvulsants, steroids, vasodilators, antiinflammatories, anticoagulants, analgesics, and other agents have been determined. An excellent correlation with the known local anesthetic activity of many of these agents indicate that antagonism of binding of [3H]BTX-B binding provides a rapid, quantitative, and facile method for the screening and investigation of local anesthetic activity.
|
Inhibition of binding of Batrachotoxinin [3H]BTX-B to high-affinity sites on voltage-dependent sodium channels in a vesicular preparation from guinea pig cerebral cortex at 100 uM
|
Cavia porcellus
|
7.7
%
|
|
Journal : J. Med. Chem.
Title : [3H]Batrachotoxinin A 20 alpha-benzoate binding to voltage-sensitive sodium channels: a rapid and quantitative assay for local anesthetic activity in a variety of drugs.
Year : 1985
Volume : 28
Issue : 3
First Page : 381
Last Page : 388
Authors : McNeal ET, Lewandowski GA, Daly JW, Creveling CR.
Abstract : [3H]Batrachotoxinin A benzoate ( [3H]BTX-B) binds with high affinity to sites on voltage-dependent sodium channels in a vesicular preparation from guinea pig cerebral cortex. In this preparation, local anesthetics competitively antagonize the binding of [3H]BTX-B. The potencies of some 40 classical local anesthetics and a variety of catecholamine, histamine, serotonin, adenosine, GABA, glycine, acetylcholine, and calcium antagonists, tranquilizers, antidepressants, barbiturates, anticonvulsants, steroids, vasodilators, antiinflammatories, anticoagulants, analgesics, and other agents have been determined. An excellent correlation with the known local anesthetic activity of many of these agents indicate that antagonism of binding of [3H]BTX-B binding provides a rapid, quantitative, and facile method for the screening and investigation of local anesthetic activity.
|
Binding affinity for rat GABA-A receptor alpha-1-beta-2-gamma-2 subunits expressed in HEK293 cells
|
Rattus norvegicus
|
0.5
nM
|
|
Journal : J. Med. Chem.
Title : Four amino acid exchanges convert a diazepam-insensitive, inverse agonist-preferring GABAA receptor into a diazepam-preferring GABAA receptor.
Year : 1994
Volume : 37
Issue : 26
First Page : 4576
Last Page : 4580
Authors : Wieland HA, Lüddens H.
Abstract : Benzodiazepines (BZ) exert their effects through GABAA receptors, which belong to the superfamily of ligand-gated ion channels. Coexpression of recombinant alpha, beta, and gamma subunits in a cell culture system mimics the BZ binding sites. The alpha variants largely determine the nature of the BZ binding site in such alpha i beta j gamma k heteromultimers (i = 1-6; j = 1-3; k = 1-3). Notably, the alpha 1 and alpha 6 variants confer high and low affinity for BZ agonists to the resulting receptor subtype, respectively. Glycine/glutamate and histidine/arginine positions in the alpha subunits of alpha x beta 2 gamma 2 receptors are involved in BZ I versus BZ II type selectivity. We now identify four amino acids in alpha 6 which together increase the affinity of the mutant alpha x beta 2 gamma 2 receptor for classical BZ receptor agonists above the level seen for any wild-type GABAA/BZ receptor. The most pronounced effect was due to an isoleucine to valine exchange. It simultaneously decreased the affinity for the BZ partial inverse agonist Ro 15-4513 20-fold and increased the affinity for diazepam 4-fold. The four amino acid residues stretch over most part of the N-terminal extracellular domain of the alpha subunit, suggesting that amino acids distant in the primary sequence form the BZ binding pocket.
|
Binding affinity for mutant rat GABA-A receptor alpha-1-(arg)-beta-2-gamma-2 subunits expressed in HEK293 cells
|
Rattus norvegicus
|
106.0
nM
|
|
Journal : J. Med. Chem.
Title : Four amino acid exchanges convert a diazepam-insensitive, inverse agonist-preferring GABAA receptor into a diazepam-preferring GABAA receptor.
Year : 1994
Volume : 37
Issue : 26
First Page : 4576
Last Page : 4580
Authors : Wieland HA, Lüddens H.
Abstract : Benzodiazepines (BZ) exert their effects through GABAA receptors, which belong to the superfamily of ligand-gated ion channels. Coexpression of recombinant alpha, beta, and gamma subunits in a cell culture system mimics the BZ binding sites. The alpha variants largely determine the nature of the BZ binding site in such alpha i beta j gamma k heteromultimers (i = 1-6; j = 1-3; k = 1-3). Notably, the alpha 1 and alpha 6 variants confer high and low affinity for BZ agonists to the resulting receptor subtype, respectively. Glycine/glutamate and histidine/arginine positions in the alpha subunits of alpha x beta 2 gamma 2 receptors are involved in BZ I versus BZ II type selectivity. We now identify four amino acids in alpha 6 which together increase the affinity of the mutant alpha x beta 2 gamma 2 receptor for classical BZ receptor agonists above the level seen for any wild-type GABAA/BZ receptor. The most pronounced effect was due to an isoleucine to valine exchange. It simultaneously decreased the affinity for the BZ partial inverse agonist Ro 15-4513 20-fold and increased the affinity for diazepam 4-fold. The four amino acid residues stretch over most part of the N-terminal extracellular domain of the alpha subunit, suggesting that amino acids distant in the primary sequence form the BZ binding pocket.
|
Binding affinity against alpha-1-beta-3-gamma-2 GABAA/BzR receptor subtype.
|
Homo sapiens
|
0.8
nM
|
|
Journal : J. Med. Chem.
Title : Predictive models for GABAA/benzodiazepine receptor subtypes: studies of quantitative structure-activity relationships for imidazobenzodiazepines at five recombinant GABAA/benzodiazepine receptor subtypes [alphaxbeta3gamma2 (x = 1-3, 5, and 6)] via comparative molecular field analysis.
Year : 1998
Volume : 41
Issue : 21
First Page : 4130
Last Page : 4142
Authors : Huang Q, Liu R, Zhang P, He X, McKernan R, Gan T, Bennett DW, Cook JM.
Abstract : Affinities of a series of substituted imidazobenzodiazepines at recombinant alpha1beta3gamma2, alpha2beta3gamma2, alpha3beta3gamma2, alpha5beta3gamma2, and alpha6beta3gamma2 GABAA/benzodiazepine receptor subtypes are reported. Many of these ligands displayed high affinities (low-nanomolar to subnanomolar scale) at all five receptor subtypes. Furthermore, a number of imidazobenzodiazepines exhibited relatively good selectivity at the alpha5-containing receptor isoform. For example, ligand 27 (RY-023) demonstrated a 55-fold higher selectivity at alpha5beta3gamma2 isoforms in comparison to other receptor subtypes. The affinity ratio of alpha1 (the most prevalent subtype in the brain) to alpha5 of this series of ligands ranged from 60- to 75-fold for the most selective ligands. Studies of quantitative structure-activity relationships (QSAR) by means of comparative molecular field analysis (CoMFA) were carried out. As a result, examination of CoMFA models for all five receptor subtypes demonstrated their predictability for affinities of imidazobenzodiazepines at the five receptor subtypes. Regions of molecular fields which would favor or disfavor the binding affinity of a ligand at a specific receptor subtype were examined via CoMFA for alpha1, alpha2, alpha3, alpha5, and alpha6 subtypes. A CoMFA regression analysis was applied to predict the ratio of Ki alpha1/Ki alpha5, an index for the selectivity of a ligand at the alpha5 subtype. All of the CoMFA models offered good cross-validated correlations for the ligands in the test set as well as the ratios of Ki alpha1/Ki alpha5, which demonstrated their potential for prediction.
|
Binding affinity tested against alpha-2-beta-3-gamma-2 GABAA/BzR receptor subtype.
|
Homo sapiens
|
0.9
nM
|
|
Journal : J. Med. Chem.
Title : Predictive models for GABAA/benzodiazepine receptor subtypes: studies of quantitative structure-activity relationships for imidazobenzodiazepines at five recombinant GABAA/benzodiazepine receptor subtypes [alphaxbeta3gamma2 (x = 1-3, 5, and 6)] via comparative molecular field analysis.
Year : 1998
Volume : 41
Issue : 21
First Page : 4130
Last Page : 4142
Authors : Huang Q, Liu R, Zhang P, He X, McKernan R, Gan T, Bennett DW, Cook JM.
Abstract : Affinities of a series of substituted imidazobenzodiazepines at recombinant alpha1beta3gamma2, alpha2beta3gamma2, alpha3beta3gamma2, alpha5beta3gamma2, and alpha6beta3gamma2 GABAA/benzodiazepine receptor subtypes are reported. Many of these ligands displayed high affinities (low-nanomolar to subnanomolar scale) at all five receptor subtypes. Furthermore, a number of imidazobenzodiazepines exhibited relatively good selectivity at the alpha5-containing receptor isoform. For example, ligand 27 (RY-023) demonstrated a 55-fold higher selectivity at alpha5beta3gamma2 isoforms in comparison to other receptor subtypes. The affinity ratio of alpha1 (the most prevalent subtype in the brain) to alpha5 of this series of ligands ranged from 60- to 75-fold for the most selective ligands. Studies of quantitative structure-activity relationships (QSAR) by means of comparative molecular field analysis (CoMFA) were carried out. As a result, examination of CoMFA models for all five receptor subtypes demonstrated their predictability for affinities of imidazobenzodiazepines at the five receptor subtypes. Regions of molecular fields which would favor or disfavor the binding affinity of a ligand at a specific receptor subtype were examined via CoMFA for alpha1, alpha2, alpha3, alpha5, and alpha6 subtypes. A CoMFA regression analysis was applied to predict the ratio of Ki alpha1/Ki alpha5, an index for the selectivity of a ligand at the alpha5 subtype. All of the CoMFA models offered good cross-validated correlations for the ligands in the test set as well as the ratios of Ki alpha1/Ki alpha5, which demonstrated their potential for prediction.
|
Binding affinity for rat GABA-A receptor alpha-3-beta-2-gamma-2 subunits expressed in HEK293 cells
|
Rattus norvegicus
|
0.6
nM
|
|
Journal : J. Med. Chem.
Title : Four amino acid exchanges convert a diazepam-insensitive, inverse agonist-preferring GABAA receptor into a diazepam-preferring GABAA receptor.
Year : 1994
Volume : 37
Issue : 26
First Page : 4576
Last Page : 4580
Authors : Wieland HA, Lüddens H.
Abstract : Benzodiazepines (BZ) exert their effects through GABAA receptors, which belong to the superfamily of ligand-gated ion channels. Coexpression of recombinant alpha, beta, and gamma subunits in a cell culture system mimics the BZ binding sites. The alpha variants largely determine the nature of the BZ binding site in such alpha i beta j gamma k heteromultimers (i = 1-6; j = 1-3; k = 1-3). Notably, the alpha 1 and alpha 6 variants confer high and low affinity for BZ agonists to the resulting receptor subtype, respectively. Glycine/glutamate and histidine/arginine positions in the alpha subunits of alpha x beta 2 gamma 2 receptors are involved in BZ I versus BZ II type selectivity. We now identify four amino acids in alpha 6 which together increase the affinity of the mutant alpha x beta 2 gamma 2 receptor for classical BZ receptor agonists above the level seen for any wild-type GABAA/BZ receptor. The most pronounced effect was due to an isoleucine to valine exchange. It simultaneously decreased the affinity for the BZ partial inverse agonist Ro 15-4513 20-fold and increased the affinity for diazepam 4-fold. The four amino acid residues stretch over most part of the N-terminal extracellular domain of the alpha subunit, suggesting that amino acids distant in the primary sequence form the BZ binding pocket.
|
Binding affinity against alpha-3-beta-3-gamma-2 GABAA/BzR receptor subtype.
|
Homo sapiens
|
1.05
nM
|
|
Journal : J. Med. Chem.
Title : Predictive models for GABAA/benzodiazepine receptor subtypes: studies of quantitative structure-activity relationships for imidazobenzodiazepines at five recombinant GABAA/benzodiazepine receptor subtypes [alphaxbeta3gamma2 (x = 1-3, 5, and 6)] via comparative molecular field analysis.
Year : 1998
Volume : 41
Issue : 21
First Page : 4130
Last Page : 4142
Authors : Huang Q, Liu R, Zhang P, He X, McKernan R, Gan T, Bennett DW, Cook JM.
Abstract : Affinities of a series of substituted imidazobenzodiazepines at recombinant alpha1beta3gamma2, alpha2beta3gamma2, alpha3beta3gamma2, alpha5beta3gamma2, and alpha6beta3gamma2 GABAA/benzodiazepine receptor subtypes are reported. Many of these ligands displayed high affinities (low-nanomolar to subnanomolar scale) at all five receptor subtypes. Furthermore, a number of imidazobenzodiazepines exhibited relatively good selectivity at the alpha5-containing receptor isoform. For example, ligand 27 (RY-023) demonstrated a 55-fold higher selectivity at alpha5beta3gamma2 isoforms in comparison to other receptor subtypes. The affinity ratio of alpha1 (the most prevalent subtype in the brain) to alpha5 of this series of ligands ranged from 60- to 75-fold for the most selective ligands. Studies of quantitative structure-activity relationships (QSAR) by means of comparative molecular field analysis (CoMFA) were carried out. As a result, examination of CoMFA models for all five receptor subtypes demonstrated their predictability for affinities of imidazobenzodiazepines at the five receptor subtypes. Regions of molecular fields which would favor or disfavor the binding affinity of a ligand at a specific receptor subtype were examined via CoMFA for alpha1, alpha2, alpha3, alpha5, and alpha6 subtypes. A CoMFA regression analysis was applied to predict the ratio of Ki alpha1/Ki alpha5, an index for the selectivity of a ligand at the alpha5 subtype. All of the CoMFA models offered good cross-validated correlations for the ligands in the test set as well as the ratios of Ki alpha1/Ki alpha5, which demonstrated their potential for prediction.
|
Binding affinity for rat GABA-A receptor alpha-4-beta-2-gamma-2 subunits expressed in HEK293 cells
|
Rattus norvegicus
|
94.0
nM
|
|
Journal : J. Med. Chem.
Title : Four amino acid exchanges convert a diazepam-insensitive, inverse agonist-preferring GABAA receptor into a diazepam-preferring GABAA receptor.
Year : 1994
Volume : 37
Issue : 26
First Page : 4576
Last Page : 4580
Authors : Wieland HA, Lüddens H.
Abstract : Benzodiazepines (BZ) exert their effects through GABAA receptors, which belong to the superfamily of ligand-gated ion channels. Coexpression of recombinant alpha, beta, and gamma subunits in a cell culture system mimics the BZ binding sites. The alpha variants largely determine the nature of the BZ binding site in such alpha i beta j gamma k heteromultimers (i = 1-6; j = 1-3; k = 1-3). Notably, the alpha 1 and alpha 6 variants confer high and low affinity for BZ agonists to the resulting receptor subtype, respectively. Glycine/glutamate and histidine/arginine positions in the alpha subunits of alpha x beta 2 gamma 2 receptors are involved in BZ I versus BZ II type selectivity. We now identify four amino acids in alpha 6 which together increase the affinity of the mutant alpha x beta 2 gamma 2 receptor for classical BZ receptor agonists above the level seen for any wild-type GABAA/BZ receptor. The most pronounced effect was due to an isoleucine to valine exchange. It simultaneously decreased the affinity for the BZ partial inverse agonist Ro 15-4513 20-fold and increased the affinity for diazepam 4-fold. The four amino acid residues stretch over most part of the N-terminal extracellular domain of the alpha subunit, suggesting that amino acids distant in the primary sequence form the BZ binding pocket.
|
Binding affinity for mutant rat GABA-A receptor alpha-4-(his)-beta-2-gamma-2 subunits expressed in HEK293 cells
|
Rattus norvegicus
|
0.6
nM
|
|
Journal : J. Med. Chem.
Title : Four amino acid exchanges convert a diazepam-insensitive, inverse agonist-preferring GABAA receptor into a diazepam-preferring GABAA receptor.
Year : 1994
Volume : 37
Issue : 26
First Page : 4576
Last Page : 4580
Authors : Wieland HA, Lüddens H.
Abstract : Benzodiazepines (BZ) exert their effects through GABAA receptors, which belong to the superfamily of ligand-gated ion channels. Coexpression of recombinant alpha, beta, and gamma subunits in a cell culture system mimics the BZ binding sites. The alpha variants largely determine the nature of the BZ binding site in such alpha i beta j gamma k heteromultimers (i = 1-6; j = 1-3; k = 1-3). Notably, the alpha 1 and alpha 6 variants confer high and low affinity for BZ agonists to the resulting receptor subtype, respectively. Glycine/glutamate and histidine/arginine positions in the alpha subunits of alpha x beta 2 gamma 2 receptors are involved in BZ I versus BZ II type selectivity. We now identify four amino acids in alpha 6 which together increase the affinity of the mutant alpha x beta 2 gamma 2 receptor for classical BZ receptor agonists above the level seen for any wild-type GABAA/BZ receptor. The most pronounced effect was due to an isoleucine to valine exchange. It simultaneously decreased the affinity for the BZ partial inverse agonist Ro 15-4513 20-fold and increased the affinity for diazepam 4-fold. The four amino acid residues stretch over most part of the N-terminal extracellular domain of the alpha subunit, suggesting that amino acids distant in the primary sequence form the BZ binding pocket.
|
Binding affinity for rat GABA-A receptor alpha-5--beta-2-gamma-2 subunits expressed in HEK293 cells
|
Rattus norvegicus
|
0.5
nM
|
|
Journal : J. Med. Chem.
Title : Four amino acid exchanges convert a diazepam-insensitive, inverse agonist-preferring GABAA receptor into a diazepam-preferring GABAA receptor.
Year : 1994
Volume : 37
Issue : 26
First Page : 4576
Last Page : 4580
Authors : Wieland HA, Lüddens H.
Abstract : Benzodiazepines (BZ) exert their effects through GABAA receptors, which belong to the superfamily of ligand-gated ion channels. Coexpression of recombinant alpha, beta, and gamma subunits in a cell culture system mimics the BZ binding sites. The alpha variants largely determine the nature of the BZ binding site in such alpha i beta j gamma k heteromultimers (i = 1-6; j = 1-3; k = 1-3). Notably, the alpha 1 and alpha 6 variants confer high and low affinity for BZ agonists to the resulting receptor subtype, respectively. Glycine/glutamate and histidine/arginine positions in the alpha subunits of alpha x beta 2 gamma 2 receptors are involved in BZ I versus BZ II type selectivity. We now identify four amino acids in alpha 6 which together increase the affinity of the mutant alpha x beta 2 gamma 2 receptor for classical BZ receptor agonists above the level seen for any wild-type GABAA/BZ receptor. The most pronounced effect was due to an isoleucine to valine exchange. It simultaneously decreased the affinity for the BZ partial inverse agonist Ro 15-4513 20-fold and increased the affinity for diazepam 4-fold. The four amino acid residues stretch over most part of the N-terminal extracellular domain of the alpha subunit, suggesting that amino acids distant in the primary sequence form the BZ binding pocket.
|
Binding affinity for rat GABA-A receptor alpha-6-beta-2-gamma-2 subunits expressed in HEK293 cells
|
Rattus norvegicus
|
90.0
nM
|
|
Journal : J. Med. Chem.
Title : Four amino acid exchanges convert a diazepam-insensitive, inverse agonist-preferring GABAA receptor into a diazepam-preferring GABAA receptor.
Year : 1994
Volume : 37
Issue : 26
First Page : 4576
Last Page : 4580
Authors : Wieland HA, Lüddens H.
Abstract : Benzodiazepines (BZ) exert their effects through GABAA receptors, which belong to the superfamily of ligand-gated ion channels. Coexpression of recombinant alpha, beta, and gamma subunits in a cell culture system mimics the BZ binding sites. The alpha variants largely determine the nature of the BZ binding site in such alpha i beta j gamma k heteromultimers (i = 1-6; j = 1-3; k = 1-3). Notably, the alpha 1 and alpha 6 variants confer high and low affinity for BZ agonists to the resulting receptor subtype, respectively. Glycine/glutamate and histidine/arginine positions in the alpha subunits of alpha x beta 2 gamma 2 receptors are involved in BZ I versus BZ II type selectivity. We now identify four amino acids in alpha 6 which together increase the affinity of the mutant alpha x beta 2 gamma 2 receptor for classical BZ receptor agonists above the level seen for any wild-type GABAA/BZ receptor. The most pronounced effect was due to an isoleucine to valine exchange. It simultaneously decreased the affinity for the BZ partial inverse agonist Ro 15-4513 20-fold and increased the affinity for diazepam 4-fold. The four amino acid residues stretch over most part of the N-terminal extracellular domain of the alpha subunit, suggesting that amino acids distant in the primary sequence form the BZ binding pocket.
|
Binding affinity for mutant rat GABA-A receptor alpha-6-(his)-beta-2-gamma-2 subunits expressed in HEK293 cells
|
Rattus norvegicus
|
17.0
nM
|
|
Journal : J. Med. Chem.
Title : Four amino acid exchanges convert a diazepam-insensitive, inverse agonist-preferring GABAA receptor into a diazepam-preferring GABAA receptor.
Year : 1994
Volume : 37
Issue : 26
First Page : 4576
Last Page : 4580
Authors : Wieland HA, Lüddens H.
Abstract : Benzodiazepines (BZ) exert their effects through GABAA receptors, which belong to the superfamily of ligand-gated ion channels. Coexpression of recombinant alpha, beta, and gamma subunits in a cell culture system mimics the BZ binding sites. The alpha variants largely determine the nature of the BZ binding site in such alpha i beta j gamma k heteromultimers (i = 1-6; j = 1-3; k = 1-3). Notably, the alpha 1 and alpha 6 variants confer high and low affinity for BZ agonists to the resulting receptor subtype, respectively. Glycine/glutamate and histidine/arginine positions in the alpha subunits of alpha x beta 2 gamma 2 receptors are involved in BZ I versus BZ II type selectivity. We now identify four amino acids in alpha 6 which together increase the affinity of the mutant alpha x beta 2 gamma 2 receptor for classical BZ receptor agonists above the level seen for any wild-type GABAA/BZ receptor. The most pronounced effect was due to an isoleucine to valine exchange. It simultaneously decreased the affinity for the BZ partial inverse agonist Ro 15-4513 20-fold and increased the affinity for diazepam 4-fold. The four amino acid residues stretch over most part of the N-terminal extracellular domain of the alpha subunit, suggesting that amino acids distant in the primary sequence form the BZ binding pocket.
|
Binding affinity for mutant rat GABA-A receptor alpha-6-(his,thr)beta2gamma2 subunits expressed in HEK293 cells
|
Rattus norvegicus
|
17.0
nM
|
|
Journal : J. Med. Chem.
Title : Four amino acid exchanges convert a diazepam-insensitive, inverse agonist-preferring GABAA receptor into a diazepam-preferring GABAA receptor.
Year : 1994
Volume : 37
Issue : 26
First Page : 4576
Last Page : 4580
Authors : Wieland HA, Lüddens H.
Abstract : Benzodiazepines (BZ) exert their effects through GABAA receptors, which belong to the superfamily of ligand-gated ion channels. Coexpression of recombinant alpha, beta, and gamma subunits in a cell culture system mimics the BZ binding sites. The alpha variants largely determine the nature of the BZ binding site in such alpha i beta j gamma k heteromultimers (i = 1-6; j = 1-3; k = 1-3). Notably, the alpha 1 and alpha 6 variants confer high and low affinity for BZ agonists to the resulting receptor subtype, respectively. Glycine/glutamate and histidine/arginine positions in the alpha subunits of alpha x beta 2 gamma 2 receptors are involved in BZ I versus BZ II type selectivity. We now identify four amino acids in alpha 6 which together increase the affinity of the mutant alpha x beta 2 gamma 2 receptor for classical BZ receptor agonists above the level seen for any wild-type GABAA/BZ receptor. The most pronounced effect was due to an isoleucine to valine exchange. It simultaneously decreased the affinity for the BZ partial inverse agonist Ro 15-4513 20-fold and increased the affinity for diazepam 4-fold. The four amino acid residues stretch over most part of the N-terminal extracellular domain of the alpha subunit, suggesting that amino acids distant in the primary sequence form the BZ binding pocket.
|
Binding affinity for mutant rat GABA-A receptor alpha-6-(his,thr,gly)beta2gamma2 subunits expressed in HEK293 cells
|
Rattus norvegicus
|
15.0
nM
|
|
Journal : J. Med. Chem.
Title : Four amino acid exchanges convert a diazepam-insensitive, inverse agonist-preferring GABAA receptor into a diazepam-preferring GABAA receptor.
Year : 1994
Volume : 37
Issue : 26
First Page : 4576
Last Page : 4580
Authors : Wieland HA, Lüddens H.
Abstract : Benzodiazepines (BZ) exert their effects through GABAA receptors, which belong to the superfamily of ligand-gated ion channels. Coexpression of recombinant alpha, beta, and gamma subunits in a cell culture system mimics the BZ binding sites. The alpha variants largely determine the nature of the BZ binding site in such alpha i beta j gamma k heteromultimers (i = 1-6; j = 1-3; k = 1-3). Notably, the alpha 1 and alpha 6 variants confer high and low affinity for BZ agonists to the resulting receptor subtype, respectively. Glycine/glutamate and histidine/arginine positions in the alpha subunits of alpha x beta 2 gamma 2 receptors are involved in BZ I versus BZ II type selectivity. We now identify four amino acids in alpha 6 which together increase the affinity of the mutant alpha x beta 2 gamma 2 receptor for classical BZ receptor agonists above the level seen for any wild-type GABAA/BZ receptor. The most pronounced effect was due to an isoleucine to valine exchange. It simultaneously decreased the affinity for the BZ partial inverse agonist Ro 15-4513 20-fold and increased the affinity for diazepam 4-fold. The four amino acid residues stretch over most part of the N-terminal extracellular domain of the alpha subunit, suggesting that amino acids distant in the primary sequence form the BZ binding pocket.
|
Binding affinity for mutant rat GABA-A receptor alpha-6-(his,thr,gly,val)beta2gamma2 subunits expressed in HEK293 cells
|
Rattus norvegicus
|
33.0
nM
|
|
Journal : J. Med. Chem.
Title : Four amino acid exchanges convert a diazepam-insensitive, inverse agonist-preferring GABAA receptor into a diazepam-preferring GABAA receptor.
Year : 1994
Volume : 37
Issue : 26
First Page : 4576
Last Page : 4580
Authors : Wieland HA, Lüddens H.
Abstract : Benzodiazepines (BZ) exert their effects through GABAA receptors, which belong to the superfamily of ligand-gated ion channels. Coexpression of recombinant alpha, beta, and gamma subunits in a cell culture system mimics the BZ binding sites. The alpha variants largely determine the nature of the BZ binding site in such alpha i beta j gamma k heteromultimers (i = 1-6; j = 1-3; k = 1-3). Notably, the alpha 1 and alpha 6 variants confer high and low affinity for BZ agonists to the resulting receptor subtype, respectively. Glycine/glutamate and histidine/arginine positions in the alpha subunits of alpha x beta 2 gamma 2 receptors are involved in BZ I versus BZ II type selectivity. We now identify four amino acids in alpha 6 which together increase the affinity of the mutant alpha x beta 2 gamma 2 receptor for classical BZ receptor agonists above the level seen for any wild-type GABAA/BZ receptor. The most pronounced effect was due to an isoleucine to valine exchange. It simultaneously decreased the affinity for the BZ partial inverse agonist Ro 15-4513 20-fold and increased the affinity for diazepam 4-fold. The four amino acid residues stretch over most part of the N-terminal extracellular domain of the alpha subunit, suggesting that amino acids distant in the primary sequence form the BZ binding pocket.
|
Displacement of [3H]flumazenil from bovine benzodiazepine receptor GABA-A channel of brain membranes
|
Bos taurus
|
0.9
nM
|
|
Journal : J. Med. Chem.
Title : High affinity central benzodiazepine receptor ligands: synthesis and biological evaluation of a series of phenyltriazolobenzotriazindione derivatives.
Year : 2005
Volume : 48
Issue : 8
First Page : 2936
Last Page : 2943
Authors : Primofiore G, Da Settimo F, Taliani S, Salerno S, Novellino E, Greco G, Cosimelli B, Besnard F, Costa B, Montali M, Martini C.
Abstract : A series of 2-phenyl[1,2,3]triazolo[1,2-a][1,2,4]benzotriazin-1,5(6H)-diones (PTBTs), VII, were prepared and tested at the central benzodiazepine receptor (BzR). The skeleton of these compounds was designed by formally combining the N-C=O moieties of the known BzR ligands, triazoloquinoxalines (IV) and triazinobenzimidazoles (ATBIs) (VI). Most of the PTBTs displayed submicromolar/nanomolar potency at the BzR. The 9-chloro derivatives (45-49) were generally found to be more potent than their 9-unsubstituted counterparts (37-44). Compound 45 turned out to be the most potent of the PTBTs (K(i) 2.8 nM). A subset of compounds (37, 42, 45, 49), when tested for their affinity on recombinant rat alpha1beta2gamma2, alpha2beta2gamma2, and alpha5beta3gamma2 GABA(A)/Bz receptor subtypes, showed enhanced affinities for the alpha1beta2gamma2 isoform, with compounds 45 and 49 exhibiting the highest selectivity. Moreover, compounds 45 and 49 were found to display a full agonist efficacy profile at alpha1 and alpha2 receptor subtypes, and an antagonist efficacy at alpha5-containing receptors.
|
Displacement of [3H]flumazenil from GABA-A receptor in bovine brain membranes
|
Bos taurus
|
0.9
nM
|
|
Journal : J. Med. Chem.
Title : Refinement of the benzodiazepine receptor site topology by structure-activity relationships of new N-(heteroarylmethyl)indol-3-ylglyoxylamides.
Year : 2006
Volume : 49
Issue : 8
First Page : 2489
Last Page : 2495
Authors : Primofiore G, Da Settimo F, Marini AM, Taliani S, La Motta C, Simorini F, Novellino E, Greco G, Cosimelli B, Ehlardo M, Sala A, Besnard F, Montali M, Martini C.
Abstract : N-(heteroarylmethyl)indol-3-ylglyoxylamides (1-26) were synthesized and evaluated as ligands of the benzodiazepine receptor (BzR) to probe the hydrogen bonding properties of the so-called S(1) site of the BzR by means of suitable heterocyclic side chains. SARs were developed in light of our hypothesis of binding modes A and B. Pyrrole and furan derivatives adopting mode A (2, 8, 10, 20, 22) turned out to be more potent (K(i) values < 35 nM) than their analogues lacking hydrogen bonding heterocyclic side chains. These data suggest that the most potent indoles interact with a hydrogen bond acceptor/donor (HBA/D) group located within the S(1) site of the BzR. Compounds 1, 2, 8, 19, 20, and 22, tested at recombinant rat alpha(1)beta(2)gamma(2), alpha(2)beta(2)gamma(2), and alpha(5)beta(3)gamma(2) BzRs, elicited selectivity for the alpha(1)beta(2)gamma(2) isoform. On the basis of published mutagenesis studies and the present SARs, we speculate that the S(1) HBA/D group might be identified as the hydroxyl of alpha(1)-Tyr209 or of other neighboring amino acids.
|
Displacement of [3H]flumazenil from benzodiazepine receptor in bovine brain membranes
|
Bos taurus
|
0.9
nM
|
|
Journal : J. Med. Chem.
Title : Novel N-substituted indol-3-ylglyoxylamides probing the LDi and L1/L2 lipophilic regions of the benzodiazepine receptor site in search for subtype-selective ligands.
Year : 2007
Volume : 50
Issue : 7
First Page : 1627
Last Page : 1634
Authors : Primofiore G, Taliani S, Da Settimo F, Marini AM, La Motta C, Simorini F, Patrizi MP, Sergianni V, Novellino E, Greco G, Cosimelli B, Calderone V, Montali M, Besnard F, Martini C.
Abstract : Novel N-substituted indol-3-ylglyoxylamides (10-37) were synthesized and evaluated as ligands of the benzodiazepine receptor (BzR). In an effort to achieve affinity-based selectivity among BzR subtypes, these compounds were designed to probe the LDi and L2 lipophilic regions. Taking the alpha1-selective benzylindolylglyoxylamides Ia and Ib as leads, we varied the substituent on the benzylamide phenyl ring (compounds 10-23) or replaced the benzyl moiety with alkyl groups (compounds 24-37). The above structural changes gave no shift of selectivity from the alpha1 toward the alpha2 or alpha5 subtypes, thus confirming that a ligand which occupies the LDi region probably exhibits alpha1 selectivity, despite its interactions with other lipophilic areas in the receptor binding cleft. Compound 11 (N-(p-methylbenzyl)-5-nitroindol-3-ylglyoxylamide), which selectively binds with a full agonist efficacy at the alpha1 receptor subtype and displays sedative action, can be regarded as an interesting potential zolpidem-like sedative-hypnotic agent.
|
Displacement of [3H]flumazenil from GABAA/BzR complex in bovine cerebral cortex membrane
|
Bos taurus
|
0.9
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Novel 3-aroylpyrazolo[5,1-c][1,2,4]benzotriazine 5-oxides 8-substituted, ligands at GABAA/benzodiazepine receptor complex: synthesis, pharmacological and molecular modeling studies.
Year : 2008
Volume : 16
Issue : 8
First Page : 4471
Last Page : 4489
Authors : Guerrini G, Ciciani G, Cambi G, Bruni F, Selleri S, Melani F, Montali M, Martini C, Ghelardini C, Norcini M, Costanzo A.
Abstract : The synthesis and binding studies of a series of 3-acylpyrazolo[5,1-c][1,2,4]benzotriazine 5-oxides 8-substituted are reported. High-affinity ligands at benzodiazepine site on GABA(A) receptor complex (GABA(A)/BzR complex) were obtained when the 3-aroyl substituent is represented by a five-member heteroaroyl ring (furoyl-, thenoyl-, and pyrroyl-). Moreover the type of heteroaroyl ring at position 3 influences the feature of the substituent at position 8 to obtain high-affinity ligands: a 'hydrogen-bond acceptor ring' at position 3 is synergic with an electron donor substituent at position 8, while a 'hydrogen-bond donor ring' is synergic with a withdrawing substituent. Compounds 8a, 9b, and 11 were deeply studied in vivo for their pharmacological effects considering six potential benzodiazepine actions: motor coordination, anticonvulsant action, spontaneous motor activity and explorative activity, anxiolytic-like effects, mouse learning and memory modulation, and ethanol-potentiating action. To rationalize and qualitatively interpret the GABA(A)/Bz binding affinities of compounds 8a and 11, a dynamic molecular modeling study has been performed, with the aim of assessing the preferred geometry of protein-ligand complex.
|
Binding affinity to GABAA alpha-1-beta-2-gamma-2 receptor
|
None
|
2.0
nM
|
|
Journal : J. Med. Chem.
Title : Selective influence on contextual memory: physiochemical properties associated with selectivity of benzodiazepine ligands at GABAA receptors containing the alpha5 subunit.
Year : 2008
Volume : 51
Issue : 13
First Page : 3788
Last Page : 3803
Authors : Harris D, Clayton T, Cook J, Sahbaie P, Halliwell RF, Furtmüller R, Huck S, Sieghart W, DeLorey TM.
Abstract : Ligands that bind to the benzodiazepine binding site on the GABA A receptor can attenuate or potentiate cognition. To investigate this property, the chemical determinants favoring selective binding or selective activation of the alpha5beta2gamma2 and alpha1beta2gamma2 GABA A receptor isoforms were examined. A 3D-pharmacophore, developed from a diverse set of BDZR ligands, was used as an initial basis for multivariate discriminant, fragment, and 3D-quantitative structure-activity relationship analyses, which formed the criteria for selection of additional compounds for study. We found that the electrostatic potential near the ligands' terminal substituent correlated with its binding selectivity toward the alpha5beta2gamma2 versus alpha1beta2gamma2 isoform; while the fragment length and frontier molecular orbital energetics correlated with a compounds influence on electrophysiological activity. Compounds with promising alpha5 profiles were further assessed for their ability to attenuate scopolamine-induced contextual memory impairment in mice. Surprisingly, both weak inverse agonist and antagonists that display binding selectivity toward the alpha5beta2gamma2 isoform were able to attenuate contextual memory impairment.
|
Binding affinity to GABAA alpha-5-beta-2-gamma-2 receptor
|
None
|
0.5
nM
|
|
Journal : J. Med. Chem.
Title : Selective influence on contextual memory: physiochemical properties associated with selectivity of benzodiazepine ligands at GABAA receptors containing the alpha5 subunit.
Year : 2008
Volume : 51
Issue : 13
First Page : 3788
Last Page : 3803
Authors : Harris D, Clayton T, Cook J, Sahbaie P, Halliwell RF, Furtmüller R, Huck S, Sieghart W, DeLorey TM.
Abstract : Ligands that bind to the benzodiazepine binding site on the GABA A receptor can attenuate or potentiate cognition. To investigate this property, the chemical determinants favoring selective binding or selective activation of the alpha5beta2gamma2 and alpha1beta2gamma2 GABA A receptor isoforms were examined. A 3D-pharmacophore, developed from a diverse set of BDZR ligands, was used as an initial basis for multivariate discriminant, fragment, and 3D-quantitative structure-activity relationship analyses, which formed the criteria for selection of additional compounds for study. We found that the electrostatic potential near the ligands' terminal substituent correlated with its binding selectivity toward the alpha5beta2gamma2 versus alpha1beta2gamma2 isoform; while the fragment length and frontier molecular orbital energetics correlated with a compounds influence on electrophysiological activity. Compounds with promising alpha5 profiles were further assessed for their ability to attenuate scopolamine-induced contextual memory impairment in mice. Surprisingly, both weak inverse agonist and antagonists that display binding selectivity toward the alpha5beta2gamma2 isoform were able to attenuate contextual memory impairment.
|
Displacement of [3H]Ro15-1788 from benzodiazepine binding site of GABAA alpha-1-beta-2-gamma-2 receptor expressed in HEK293T cells
|
None
|
3.3
nM
|
|
Journal : J. Med. Chem.
Title : Structural requirements for eszopiclone and zolpidem binding to the gamma-aminobutyric acid type-A (GABAA) receptor are different.
Year : 2008
Volume : 51
Issue : 22
First Page : 7243
Last Page : 7252
Authors : Hanson SM, Morlock EV, Satyshur KA, Czajkowski C.
Abstract : The sleep-aids zolpidem and eszopiclone exert their effects by binding to and modulating gamma-aminobutyric acid type-A receptors (GABA(A)Rs), but little is known about the structural requirements for their actions. We made 24 cysteine mutations in the benzodiazepine (BZD) binding site of alpha(1)beta(2)gamma(2) GABA(A)Rs and measured zolpidem, eszopiclone, and BZD-site antagonist binding. Mutations in gamma(2)loop D and alpha(1)loops A and B altered the affinity of all ligands tested, indicating that these loops are important for BZD pocket structural integrity. In contrast, gamma(2)loop E and alpha(1)loop C mutations differentially affected ligand affinity, suggesting that these loops are important for ligand selectivity. In agreement with our mutagenesis data, eszopiclone docking yielded a single model stabilized by several hydrogen bonds. Zolpidem docking yielded three equally populated orientations with few polar interactions, suggesting that unlike eszopiclone, zolpidem relies more on shape recognition of the binding pocket than on specific residue interactions and may explain why zolpidem is highly alpha(1)- and gamma(2)-subunit selective.
|
Displacement of [3H]Ro-151788 from benzodiazepine binding site of GABAA alpha-2-beta-2-gamma-2 receptor expressed in HEK293T cells
|
None
|
5.7
nM
|
|
Journal : J. Med. Chem.
Title : Structural requirements for eszopiclone and zolpidem binding to the gamma-aminobutyric acid type-A (GABAA) receptor are different.
Year : 2008
Volume : 51
Issue : 22
First Page : 7243
Last Page : 7252
Authors : Hanson SM, Morlock EV, Satyshur KA, Czajkowski C.
Abstract : The sleep-aids zolpidem and eszopiclone exert their effects by binding to and modulating gamma-aminobutyric acid type-A receptors (GABA(A)Rs), but little is known about the structural requirements for their actions. We made 24 cysteine mutations in the benzodiazepine (BZD) binding site of alpha(1)beta(2)gamma(2) GABA(A)Rs and measured zolpidem, eszopiclone, and BZD-site antagonist binding. Mutations in gamma(2)loop D and alpha(1)loops A and B altered the affinity of all ligands tested, indicating that these loops are important for BZD pocket structural integrity. In contrast, gamma(2)loop E and alpha(1)loop C mutations differentially affected ligand affinity, suggesting that these loops are important for ligand selectivity. In agreement with our mutagenesis data, eszopiclone docking yielded a single model stabilized by several hydrogen bonds. Zolpidem docking yielded three equally populated orientations with few polar interactions, suggesting that unlike eszopiclone, zolpidem relies more on shape recognition of the binding pocket than on specific residue interactions and may explain why zolpidem is highly alpha(1)- and gamma(2)-subunit selective.
|
Displacement of [3H]Ro-154513 from benzodiazepine binding site of GABAA alpha-4-beta-2-gamma-2 receptor expressed in HEK293T cells
|
None
|
2.0
nM
|
|
Journal : J. Med. Chem.
Title : Structural requirements for eszopiclone and zolpidem binding to the gamma-aminobutyric acid type-A (GABAA) receptor are different.
Year : 2008
Volume : 51
Issue : 22
First Page : 7243
Last Page : 7252
Authors : Hanson SM, Morlock EV, Satyshur KA, Czajkowski C.
Abstract : The sleep-aids zolpidem and eszopiclone exert their effects by binding to and modulating gamma-aminobutyric acid type-A receptors (GABA(A)Rs), but little is known about the structural requirements for their actions. We made 24 cysteine mutations in the benzodiazepine (BZD) binding site of alpha(1)beta(2)gamma(2) GABA(A)Rs and measured zolpidem, eszopiclone, and BZD-site antagonist binding. Mutations in gamma(2)loop D and alpha(1)loops A and B altered the affinity of all ligands tested, indicating that these loops are important for BZD pocket structural integrity. In contrast, gamma(2)loop E and alpha(1)loop C mutations differentially affected ligand affinity, suggesting that these loops are important for ligand selectivity. In agreement with our mutagenesis data, eszopiclone docking yielded a single model stabilized by several hydrogen bonds. Zolpidem docking yielded three equally populated orientations with few polar interactions, suggesting that unlike eszopiclone, zolpidem relies more on shape recognition of the binding pocket than on specific residue interactions and may explain why zolpidem is highly alpha(1)- and gamma(2)-subunit selective.
|
Displacement of [3H]Ro-151788 from benzodiazepine binding site of GABAA alpha-1-beta-2-gamma-2 D56C receptor mutant expressed in HEK293T cells
|
None
|
3.1
nM
|
|
Journal : J. Med. Chem.
Title : Structural requirements for eszopiclone and zolpidem binding to the gamma-aminobutyric acid type-A (GABAA) receptor are different.
Year : 2008
Volume : 51
Issue : 22
First Page : 7243
Last Page : 7252
Authors : Hanson SM, Morlock EV, Satyshur KA, Czajkowski C.
Abstract : The sleep-aids zolpidem and eszopiclone exert their effects by binding to and modulating gamma-aminobutyric acid type-A receptors (GABA(A)Rs), but little is known about the structural requirements for their actions. We made 24 cysteine mutations in the benzodiazepine (BZD) binding site of alpha(1)beta(2)gamma(2) GABA(A)Rs and measured zolpidem, eszopiclone, and BZD-site antagonist binding. Mutations in gamma(2)loop D and alpha(1)loops A and B altered the affinity of all ligands tested, indicating that these loops are important for BZD pocket structural integrity. In contrast, gamma(2)loop E and alpha(1)loop C mutations differentially affected ligand affinity, suggesting that these loops are important for ligand selectivity. In agreement with our mutagenesis data, eszopiclone docking yielded a single model stabilized by several hydrogen bonds. Zolpidem docking yielded three equally populated orientations with few polar interactions, suggesting that unlike eszopiclone, zolpidem relies more on shape recognition of the binding pocket than on specific residue interactions and may explain why zolpidem is highly alpha(1)- and gamma(2)-subunit selective.
|
Displacement of [3H]Ro-151788 from benzodiazepine binding site of GABAA alpha-1-beta-2-gamma-2 A79C receptor mutant expressed in HEK293T cells
|
None
|
9.2
nM
|
|
Journal : J. Med. Chem.
Title : Structural requirements for eszopiclone and zolpidem binding to the gamma-aminobutyric acid type-A (GABAA) receptor are different.
Year : 2008
Volume : 51
Issue : 22
First Page : 7243
Last Page : 7252
Authors : Hanson SM, Morlock EV, Satyshur KA, Czajkowski C.
Abstract : The sleep-aids zolpidem and eszopiclone exert their effects by binding to and modulating gamma-aminobutyric acid type-A receptors (GABA(A)Rs), but little is known about the structural requirements for their actions. We made 24 cysteine mutations in the benzodiazepine (BZD) binding site of alpha(1)beta(2)gamma(2) GABA(A)Rs and measured zolpidem, eszopiclone, and BZD-site antagonist binding. Mutations in gamma(2)loop D and alpha(1)loops A and B altered the affinity of all ligands tested, indicating that these loops are important for BZD pocket structural integrity. In contrast, gamma(2)loop E and alpha(1)loop C mutations differentially affected ligand affinity, suggesting that these loops are important for ligand selectivity. In agreement with our mutagenesis data, eszopiclone docking yielded a single model stabilized by several hydrogen bonds. Zolpidem docking yielded three equally populated orientations with few polar interactions, suggesting that unlike eszopiclone, zolpidem relies more on shape recognition of the binding pocket than on specific residue interactions and may explain why zolpidem is highly alpha(1)- and gamma(2)-subunit selective.
|
Displacement of [3H]Ro-151788 from benzodiazepine binding site of GABAA alpha-1-beta-2-gamma-2 T81C receptor mutant expressed in HEK293T cells
|
None
|
4.4
nM
|
|
Journal : J. Med. Chem.
Title : Structural requirements for eszopiclone and zolpidem binding to the gamma-aminobutyric acid type-A (GABAA) receptor are different.
Year : 2008
Volume : 51
Issue : 22
First Page : 7243
Last Page : 7252
Authors : Hanson SM, Morlock EV, Satyshur KA, Czajkowski C.
Abstract : The sleep-aids zolpidem and eszopiclone exert their effects by binding to and modulating gamma-aminobutyric acid type-A receptors (GABA(A)Rs), but little is known about the structural requirements for their actions. We made 24 cysteine mutations in the benzodiazepine (BZD) binding site of alpha(1)beta(2)gamma(2) GABA(A)Rs and measured zolpidem, eszopiclone, and BZD-site antagonist binding. Mutations in gamma(2)loop D and alpha(1)loops A and B altered the affinity of all ligands tested, indicating that these loops are important for BZD pocket structural integrity. In contrast, gamma(2)loop E and alpha(1)loop C mutations differentially affected ligand affinity, suggesting that these loops are important for ligand selectivity. In agreement with our mutagenesis data, eszopiclone docking yielded a single model stabilized by several hydrogen bonds. Zolpidem docking yielded three equally populated orientations with few polar interactions, suggesting that unlike eszopiclone, zolpidem relies more on shape recognition of the binding pocket than on specific residue interactions and may explain why zolpidem is highly alpha(1)- and gamma(2)-subunit selective.
|
Displacement of [3H]Ro-151788 from benzodiazepine binding site of GABAA alpha-1-beta-2-gamma-2 T126C receptor mutant expressed in HEK293T cells
|
None
|
4.4
nM
|
|
Journal : J. Med. Chem.
Title : Structural requirements for eszopiclone and zolpidem binding to the gamma-aminobutyric acid type-A (GABAA) receptor are different.
Year : 2008
Volume : 51
Issue : 22
First Page : 7243
Last Page : 7252
Authors : Hanson SM, Morlock EV, Satyshur KA, Czajkowski C.
Abstract : The sleep-aids zolpidem and eszopiclone exert their effects by binding to and modulating gamma-aminobutyric acid type-A receptors (GABA(A)Rs), but little is known about the structural requirements for their actions. We made 24 cysteine mutations in the benzodiazepine (BZD) binding site of alpha(1)beta(2)gamma(2) GABA(A)Rs and measured zolpidem, eszopiclone, and BZD-site antagonist binding. Mutations in gamma(2)loop D and alpha(1)loops A and B altered the affinity of all ligands tested, indicating that these loops are important for BZD pocket structural integrity. In contrast, gamma(2)loop E and alpha(1)loop C mutations differentially affected ligand affinity, suggesting that these loops are important for ligand selectivity. In agreement with our mutagenesis data, eszopiclone docking yielded a single model stabilized by several hydrogen bonds. Zolpidem docking yielded three equally populated orientations with few polar interactions, suggesting that unlike eszopiclone, zolpidem relies more on shape recognition of the binding pocket than on specific residue interactions and may explain why zolpidem is highly alpha(1)- and gamma(2)-subunit selective.
|
Displacement of [3H]Ro-151788 from benzodiazepine binding site of GABAA alpha-1-beta-2-gamma-2 M130C receptor mutant expressed in HEK293T cells
|
None
|
13.8
nM
|
|
Journal : J. Med. Chem.
Title : Structural requirements for eszopiclone and zolpidem binding to the gamma-aminobutyric acid type-A (GABAA) receptor are different.
Year : 2008
Volume : 51
Issue : 22
First Page : 7243
Last Page : 7252
Authors : Hanson SM, Morlock EV, Satyshur KA, Czajkowski C.
Abstract : The sleep-aids zolpidem and eszopiclone exert their effects by binding to and modulating gamma-aminobutyric acid type-A receptors (GABA(A)Rs), but little is known about the structural requirements for their actions. We made 24 cysteine mutations in the benzodiazepine (BZD) binding site of alpha(1)beta(2)gamma(2) GABA(A)Rs and measured zolpidem, eszopiclone, and BZD-site antagonist binding. Mutations in gamma(2)loop D and alpha(1)loops A and B altered the affinity of all ligands tested, indicating that these loops are important for BZD pocket structural integrity. In contrast, gamma(2)loop E and alpha(1)loop C mutations differentially affected ligand affinity, suggesting that these loops are important for ligand selectivity. In agreement with our mutagenesis data, eszopiclone docking yielded a single model stabilized by several hydrogen bonds. Zolpidem docking yielded three equally populated orientations with few polar interactions, suggesting that unlike eszopiclone, zolpidem relies more on shape recognition of the binding pocket than on specific residue interactions and may explain why zolpidem is highly alpha(1)- and gamma(2)-subunit selective.
|
Displacement of [3H]Ro-151788 from benzodiazepine binding site of GABAA alpha-1-beta-2-gamma-2 R132C receptor mutant expressed in HEK293T cells
|
None
|
13.0
nM
|
|
Journal : J. Med. Chem.
Title : Structural requirements for eszopiclone and zolpidem binding to the gamma-aminobutyric acid type-A (GABAA) receptor are different.
Year : 2008
Volume : 51
Issue : 22
First Page : 7243
Last Page : 7252
Authors : Hanson SM, Morlock EV, Satyshur KA, Czajkowski C.
Abstract : The sleep-aids zolpidem and eszopiclone exert their effects by binding to and modulating gamma-aminobutyric acid type-A receptors (GABA(A)Rs), but little is known about the structural requirements for their actions. We made 24 cysteine mutations in the benzodiazepine (BZD) binding site of alpha(1)beta(2)gamma(2) GABA(A)Rs and measured zolpidem, eszopiclone, and BZD-site antagonist binding. Mutations in gamma(2)loop D and alpha(1)loops A and B altered the affinity of all ligands tested, indicating that these loops are important for BZD pocket structural integrity. In contrast, gamma(2)loop E and alpha(1)loop C mutations differentially affected ligand affinity, suggesting that these loops are important for ligand selectivity. In agreement with our mutagenesis data, eszopiclone docking yielded a single model stabilized by several hydrogen bonds. Zolpidem docking yielded three equally populated orientations with few polar interactions, suggesting that unlike eszopiclone, zolpidem relies more on shape recognition of the binding pocket than on specific residue interactions and may explain why zolpidem is highly alpha(1)- and gamma(2)-subunit selective.
|
Displacement of [3H]Ro-151788 from benzodiazepine binding site of GABAA alpha-1-beta-2-gamma-2 L140C receptor mutant expressed in HEK293T cells
|
None
|
3.8
nM
|
|
Journal : J. Med. Chem.
Title : Structural requirements for eszopiclone and zolpidem binding to the gamma-aminobutyric acid type-A (GABAA) receptor are different.
Year : 2008
Volume : 51
Issue : 22
First Page : 7243
Last Page : 7252
Authors : Hanson SM, Morlock EV, Satyshur KA, Czajkowski C.
Abstract : The sleep-aids zolpidem and eszopiclone exert their effects by binding to and modulating gamma-aminobutyric acid type-A receptors (GABA(A)Rs), but little is known about the structural requirements for their actions. We made 24 cysteine mutations in the benzodiazepine (BZD) binding site of alpha(1)beta(2)gamma(2) GABA(A)Rs and measured zolpidem, eszopiclone, and BZD-site antagonist binding. Mutations in gamma(2)loop D and alpha(1)loops A and B altered the affinity of all ligands tested, indicating that these loops are important for BZD pocket structural integrity. In contrast, gamma(2)loop E and alpha(1)loop C mutations differentially affected ligand affinity, suggesting that these loops are important for ligand selectivity. In agreement with our mutagenesis data, eszopiclone docking yielded a single model stabilized by several hydrogen bonds. Zolpidem docking yielded three equally populated orientations with few polar interactions, suggesting that unlike eszopiclone, zolpidem relies more on shape recognition of the binding pocket than on specific residue interactions and may explain why zolpidem is highly alpha(1)- and gamma(2)-subunit selective.
|
Displacement of [3H]Ro-151788 from benzodiazepine binding site of GABAA alpha-1-beta-2-gamma-2 T142C receptor mutant expressed in HEK293T cells
|
None
|
9.2
nM
|
|
Journal : J. Med. Chem.
Title : Structural requirements for eszopiclone and zolpidem binding to the gamma-aminobutyric acid type-A (GABAA) receptor are different.
Year : 2008
Volume : 51
Issue : 22
First Page : 7243
Last Page : 7252
Authors : Hanson SM, Morlock EV, Satyshur KA, Czajkowski C.
Abstract : The sleep-aids zolpidem and eszopiclone exert their effects by binding to and modulating gamma-aminobutyric acid type-A receptors (GABA(A)Rs), but little is known about the structural requirements for their actions. We made 24 cysteine mutations in the benzodiazepine (BZD) binding site of alpha(1)beta(2)gamma(2) GABA(A)Rs and measured zolpidem, eszopiclone, and BZD-site antagonist binding. Mutations in gamma(2)loop D and alpha(1)loops A and B altered the affinity of all ligands tested, indicating that these loops are important for BZD pocket structural integrity. In contrast, gamma(2)loop E and alpha(1)loop C mutations differentially affected ligand affinity, suggesting that these loops are important for ligand selectivity. In agreement with our mutagenesis data, eszopiclone docking yielded a single model stabilized by several hydrogen bonds. Zolpidem docking yielded three equally populated orientations with few polar interactions, suggesting that unlike eszopiclone, zolpidem relies more on shape recognition of the binding pocket than on specific residue interactions and may explain why zolpidem is highly alpha(1)- and gamma(2)-subunit selective.
|
Displacement of [3H]Ro-151788 from benzodiazepine binding site of GABAA alpha-1-beta-2-gamma-2 R144C receptor mutant expressed in HEK293T cells
|
None
|
3.7
nM
|
|
Journal : J. Med. Chem.
Title : Structural requirements for eszopiclone and zolpidem binding to the gamma-aminobutyric acid type-A (GABAA) receptor are different.
Year : 2008
Volume : 51
Issue : 22
First Page : 7243
Last Page : 7252
Authors : Hanson SM, Morlock EV, Satyshur KA, Czajkowski C.
Abstract : The sleep-aids zolpidem and eszopiclone exert their effects by binding to and modulating gamma-aminobutyric acid type-A receptors (GABA(A)Rs), but little is known about the structural requirements for their actions. We made 24 cysteine mutations in the benzodiazepine (BZD) binding site of alpha(1)beta(2)gamma(2) GABA(A)Rs and measured zolpidem, eszopiclone, and BZD-site antagonist binding. Mutations in gamma(2)loop D and alpha(1)loops A and B altered the affinity of all ligands tested, indicating that these loops are important for BZD pocket structural integrity. In contrast, gamma(2)loop E and alpha(1)loop C mutations differentially affected ligand affinity, suggesting that these loops are important for ligand selectivity. In agreement with our mutagenesis data, eszopiclone docking yielded a single model stabilized by several hydrogen bonds. Zolpidem docking yielded three equally populated orientations with few polar interactions, suggesting that unlike eszopiclone, zolpidem relies more on shape recognition of the binding pocket than on specific residue interactions and may explain why zolpidem is highly alpha(1)- and gamma(2)-subunit selective.
|
Displacement of [3H]Ro-151788 from benzodiazepine binding site of GABAA alpha-1-beta-2-gamma-2 X161 receptor mutant expressed in HEK293T cells
|
None
|
9.6
nM
|
|
Journal : J. Med. Chem.
Title : Structural requirements for eszopiclone and zolpidem binding to the gamma-aminobutyric acid type-A (GABAA) receptor are different.
Year : 2008
Volume : 51
Issue : 22
First Page : 7243
Last Page : 7252
Authors : Hanson SM, Morlock EV, Satyshur KA, Czajkowski C.
Abstract : The sleep-aids zolpidem and eszopiclone exert their effects by binding to and modulating gamma-aminobutyric acid type-A receptors (GABA(A)Rs), but little is known about the structural requirements for their actions. We made 24 cysteine mutations in the benzodiazepine (BZD) binding site of alpha(1)beta(2)gamma(2) GABA(A)Rs and measured zolpidem, eszopiclone, and BZD-site antagonist binding. Mutations in gamma(2)loop D and alpha(1)loops A and B altered the affinity of all ligands tested, indicating that these loops are important for BZD pocket structural integrity. In contrast, gamma(2)loop E and alpha(1)loop C mutations differentially affected ligand affinity, suggesting that these loops are important for ligand selectivity. In agreement with our mutagenesis data, eszopiclone docking yielded a single model stabilized by several hydrogen bonds. Zolpidem docking yielded three equally populated orientations with few polar interactions, suggesting that unlike eszopiclone, zolpidem relies more on shape recognition of the binding pocket than on specific residue interactions and may explain why zolpidem is highly alpha(1)- and gamma(2)-subunit selective.
|
Displacement of [3H]Ro-151788 from benzodiazepine binding site of GABAA alpha-1-beta-2-gamma-2 R185C receptor mutant expressed in HEK293T cells
|
None
|
3.3
nM
|
|
Journal : J. Med. Chem.
Title : Structural requirements for eszopiclone and zolpidem binding to the gamma-aminobutyric acid type-A (GABAA) receptor are different.
Year : 2008
Volume : 51
Issue : 22
First Page : 7243
Last Page : 7252
Authors : Hanson SM, Morlock EV, Satyshur KA, Czajkowski C.
Abstract : The sleep-aids zolpidem and eszopiclone exert their effects by binding to and modulating gamma-aminobutyric acid type-A receptors (GABA(A)Rs), but little is known about the structural requirements for their actions. We made 24 cysteine mutations in the benzodiazepine (BZD) binding site of alpha(1)beta(2)gamma(2) GABA(A)Rs and measured zolpidem, eszopiclone, and BZD-site antagonist binding. Mutations in gamma(2)loop D and alpha(1)loops A and B altered the affinity of all ligands tested, indicating that these loops are important for BZD pocket structural integrity. In contrast, gamma(2)loop E and alpha(1)loop C mutations differentially affected ligand affinity, suggesting that these loops are important for ligand selectivity. In agreement with our mutagenesis data, eszopiclone docking yielded a single model stabilized by several hydrogen bonds. Zolpidem docking yielded three equally populated orientations with few polar interactions, suggesting that unlike eszopiclone, zolpidem relies more on shape recognition of the binding pocket than on specific residue interactions and may explain why zolpidem is highly alpha(1)- and gamma(2)-subunit selective.
|
Displacement of [3H]Ro-151788 from benzodiazepine binding site of GABAA alpha-1-beta-2-gamma-2 R194C receptor mutant expressed in HEK293T cells
|
None
|
4.1
nM
|
|
Journal : J. Med. Chem.
Title : Structural requirements for eszopiclone and zolpidem binding to the gamma-aminobutyric acid type-A (GABAA) receptor are different.
Year : 2008
Volume : 51
Issue : 22
First Page : 7243
Last Page : 7252
Authors : Hanson SM, Morlock EV, Satyshur KA, Czajkowski C.
Abstract : The sleep-aids zolpidem and eszopiclone exert their effects by binding to and modulating gamma-aminobutyric acid type-A receptors (GABA(A)Rs), but little is known about the structural requirements for their actions. We made 24 cysteine mutations in the benzodiazepine (BZD) binding site of alpha(1)beta(2)gamma(2) GABA(A)Rs and measured zolpidem, eszopiclone, and BZD-site antagonist binding. Mutations in gamma(2)loop D and alpha(1)loops A and B altered the affinity of all ligands tested, indicating that these loops are important for BZD pocket structural integrity. In contrast, gamma(2)loop E and alpha(1)loop C mutations differentially affected ligand affinity, suggesting that these loops are important for ligand selectivity. In agreement with our mutagenesis data, eszopiclone docking yielded a single model stabilized by several hydrogen bonds. Zolpidem docking yielded three equally populated orientations with few polar interactions, suggesting that unlike eszopiclone, zolpidem relies more on shape recognition of the binding pocket than on specific residue interactions and may explain why zolpidem is highly alpha(1)- and gamma(2)-subunit selective.
|
Displacement of [3H]Ro15-1788 from benzodiazepine binding site of GABAA alpha-1 F99C beta2gamma2 receptor mutant expressed in HEK293T cells
|
None
|
15.0
nM
|
|
Journal : J. Med. Chem.
Title : Structural requirements for eszopiclone and zolpidem binding to the gamma-aminobutyric acid type-A (GABAA) receptor are different.
Year : 2008
Volume : 51
Issue : 22
First Page : 7243
Last Page : 7252
Authors : Hanson SM, Morlock EV, Satyshur KA, Czajkowski C.
Abstract : The sleep-aids zolpidem and eszopiclone exert their effects by binding to and modulating gamma-aminobutyric acid type-A receptors (GABA(A)Rs), but little is known about the structural requirements for their actions. We made 24 cysteine mutations in the benzodiazepine (BZD) binding site of alpha(1)beta(2)gamma(2) GABA(A)Rs and measured zolpidem, eszopiclone, and BZD-site antagonist binding. Mutations in gamma(2)loop D and alpha(1)loops A and B altered the affinity of all ligands tested, indicating that these loops are important for BZD pocket structural integrity. In contrast, gamma(2)loop E and alpha(1)loop C mutations differentially affected ligand affinity, suggesting that these loops are important for ligand selectivity. In agreement with our mutagenesis data, eszopiclone docking yielded a single model stabilized by several hydrogen bonds. Zolpidem docking yielded three equally populated orientations with few polar interactions, suggesting that unlike eszopiclone, zolpidem relies more on shape recognition of the binding pocket than on specific residue interactions and may explain why zolpidem is highly alpha(1)- and gamma(2)-subunit selective.
|
Displacement of [3H]Ro15-1788 from benzodiazepine binding site of GABAA alpha-1 G157C beta2gamma2 receptor mutant expressed in HEK293T cells
|
None
|
0.19
nM
|
|
Journal : J. Med. Chem.
Title : Structural requirements for eszopiclone and zolpidem binding to the gamma-aminobutyric acid type-A (GABAA) receptor are different.
Year : 2008
Volume : 51
Issue : 22
First Page : 7243
Last Page : 7252
Authors : Hanson SM, Morlock EV, Satyshur KA, Czajkowski C.
Abstract : The sleep-aids zolpidem and eszopiclone exert their effects by binding to and modulating gamma-aminobutyric acid type-A receptors (GABA(A)Rs), but little is known about the structural requirements for their actions. We made 24 cysteine mutations in the benzodiazepine (BZD) binding site of alpha(1)beta(2)gamma(2) GABA(A)Rs and measured zolpidem, eszopiclone, and BZD-site antagonist binding. Mutations in gamma(2)loop D and alpha(1)loops A and B altered the affinity of all ligands tested, indicating that these loops are important for BZD pocket structural integrity. In contrast, gamma(2)loop E and alpha(1)loop C mutations differentially affected ligand affinity, suggesting that these loops are important for ligand selectivity. In agreement with our mutagenesis data, eszopiclone docking yielded a single model stabilized by several hydrogen bonds. Zolpidem docking yielded three equally populated orientations with few polar interactions, suggesting that unlike eszopiclone, zolpidem relies more on shape recognition of the binding pocket than on specific residue interactions and may explain why zolpidem is highly alpha(1)- and gamma(2)-subunit selective.
|
Displacement of [3H]Ro-151788 from benzodiazepine binding site of GABAA alpha1 A160C beta2gamma2 receptor mutant expressed in HEK293T cells
|
None
|
4.0
nM
|
|
Journal : J. Med. Chem.
Title : Structural requirements for eszopiclone and zolpidem binding to the gamma-aminobutyric acid type-A (GABAA) receptor are different.
Year : 2008
Volume : 51
Issue : 22
First Page : 7243
Last Page : 7252
Authors : Hanson SM, Morlock EV, Satyshur KA, Czajkowski C.
Abstract : The sleep-aids zolpidem and eszopiclone exert their effects by binding to and modulating gamma-aminobutyric acid type-A receptors (GABA(A)Rs), but little is known about the structural requirements for their actions. We made 24 cysteine mutations in the benzodiazepine (BZD) binding site of alpha(1)beta(2)gamma(2) GABA(A)Rs and measured zolpidem, eszopiclone, and BZD-site antagonist binding. Mutations in gamma(2)loop D and alpha(1)loops A and B altered the affinity of all ligands tested, indicating that these loops are important for BZD pocket structural integrity. In contrast, gamma(2)loop E and alpha(1)loop C mutations differentially affected ligand affinity, suggesting that these loops are important for ligand selectivity. In agreement with our mutagenesis data, eszopiclone docking yielded a single model stabilized by several hydrogen bonds. Zolpidem docking yielded three equally populated orientations with few polar interactions, suggesting that unlike eszopiclone, zolpidem relies more on shape recognition of the binding pocket than on specific residue interactions and may explain why zolpidem is highly alpha(1)- and gamma(2)-subunit selective.
|
Displacement of [3H]Ro15-1788 from benzodiazepine binding site of GABAA alpha1 T162C beta-2-gamma-2 receptor mutant expressed in HEK293T cells
|
None
|
2.2
nM
|
|
Journal : J. Med. Chem.
Title : Structural requirements for eszopiclone and zolpidem binding to the gamma-aminobutyric acid type-A (GABAA) receptor are different.
Year : 2008
Volume : 51
Issue : 22
First Page : 7243
Last Page : 7252
Authors : Hanson SM, Morlock EV, Satyshur KA, Czajkowski C.
Abstract : The sleep-aids zolpidem and eszopiclone exert their effects by binding to and modulating gamma-aminobutyric acid type-A receptors (GABA(A)Rs), but little is known about the structural requirements for their actions. We made 24 cysteine mutations in the benzodiazepine (BZD) binding site of alpha(1)beta(2)gamma(2) GABA(A)Rs and measured zolpidem, eszopiclone, and BZD-site antagonist binding. Mutations in gamma(2)loop D and alpha(1)loops A and B altered the affinity of all ligands tested, indicating that these loops are important for BZD pocket structural integrity. In contrast, gamma(2)loop E and alpha(1)loop C mutations differentially affected ligand affinity, suggesting that these loops are important for ligand selectivity. In agreement with our mutagenesis data, eszopiclone docking yielded a single model stabilized by several hydrogen bonds. Zolpidem docking yielded three equally populated orientations with few polar interactions, suggesting that unlike eszopiclone, zolpidem relies more on shape recognition of the binding pocket than on specific residue interactions and may explain why zolpidem is highly alpha(1)- and gamma(2)-subunit selective.
|
Displacement of [3H]Ro15-1788 from benzodiazepine binding site of GABAA alpha-1 G200C beta2gamma2 receptor mutant expressed in HEK293T cells
|
None
|
3.0
nM
|
|
Journal : J. Med. Chem.
Title : Structural requirements for eszopiclone and zolpidem binding to the gamma-aminobutyric acid type-A (GABAA) receptor are different.
Year : 2008
Volume : 51
Issue : 22
First Page : 7243
Last Page : 7252
Authors : Hanson SM, Morlock EV, Satyshur KA, Czajkowski C.
Abstract : The sleep-aids zolpidem and eszopiclone exert their effects by binding to and modulating gamma-aminobutyric acid type-A receptors (GABA(A)Rs), but little is known about the structural requirements for their actions. We made 24 cysteine mutations in the benzodiazepine (BZD) binding site of alpha(1)beta(2)gamma(2) GABA(A)Rs and measured zolpidem, eszopiclone, and BZD-site antagonist binding. Mutations in gamma(2)loop D and alpha(1)loops A and B altered the affinity of all ligands tested, indicating that these loops are important for BZD pocket structural integrity. In contrast, gamma(2)loop E and alpha(1)loop C mutations differentially affected ligand affinity, suggesting that these loops are important for ligand selectivity. In agreement with our mutagenesis data, eszopiclone docking yielded a single model stabilized by several hydrogen bonds. Zolpidem docking yielded three equally populated orientations with few polar interactions, suggesting that unlike eszopiclone, zolpidem relies more on shape recognition of the binding pocket than on specific residue interactions and may explain why zolpidem is highly alpha(1)- and gamma(2)-subunit selective.
|
Displacement of [3H]Ro-151788 from benzodiazepine binding site of GABAA alpha1 V202C beta2gamma2 receptor mutant expressed in HEK293T cells
|
None
|
1.5
nM
|
|
Journal : J. Med. Chem.
Title : Structural requirements for eszopiclone and zolpidem binding to the gamma-aminobutyric acid type-A (GABAA) receptor are different.
Year : 2008
Volume : 51
Issue : 22
First Page : 7243
Last Page : 7252
Authors : Hanson SM, Morlock EV, Satyshur KA, Czajkowski C.
Abstract : The sleep-aids zolpidem and eszopiclone exert their effects by binding to and modulating gamma-aminobutyric acid type-A receptors (GABA(A)Rs), but little is known about the structural requirements for their actions. We made 24 cysteine mutations in the benzodiazepine (BZD) binding site of alpha(1)beta(2)gamma(2) GABA(A)Rs and measured zolpidem, eszopiclone, and BZD-site antagonist binding. Mutations in gamma(2)loop D and alpha(1)loops A and B altered the affinity of all ligands tested, indicating that these loops are important for BZD pocket structural integrity. In contrast, gamma(2)loop E and alpha(1)loop C mutations differentially affected ligand affinity, suggesting that these loops are important for ligand selectivity. In agreement with our mutagenesis data, eszopiclone docking yielded a single model stabilized by several hydrogen bonds. Zolpidem docking yielded three equally populated orientations with few polar interactions, suggesting that unlike eszopiclone, zolpidem relies more on shape recognition of the binding pocket than on specific residue interactions and may explain why zolpidem is highly alpha(1)- and gamma(2)-subunit selective.
|
Displacement of [3H]Ro-151788 from benzodiazepine binding site of GABAA alpha1 S204C beta2gamma2 receptor mutant expressed in HEK293T cells
|
None
|
8.8
nM
|
|
Journal : J. Med. Chem.
Title : Structural requirements for eszopiclone and zolpidem binding to the gamma-aminobutyric acid type-A (GABAA) receptor are different.
Year : 2008
Volume : 51
Issue : 22
First Page : 7243
Last Page : 7252
Authors : Hanson SM, Morlock EV, Satyshur KA, Czajkowski C.
Abstract : The sleep-aids zolpidem and eszopiclone exert their effects by binding to and modulating gamma-aminobutyric acid type-A receptors (GABA(A)Rs), but little is known about the structural requirements for their actions. We made 24 cysteine mutations in the benzodiazepine (BZD) binding site of alpha(1)beta(2)gamma(2) GABA(A)Rs and measured zolpidem, eszopiclone, and BZD-site antagonist binding. Mutations in gamma(2)loop D and alpha(1)loops A and B altered the affinity of all ligands tested, indicating that these loops are important for BZD pocket structural integrity. In contrast, gamma(2)loop E and alpha(1)loop C mutations differentially affected ligand affinity, suggesting that these loops are important for ligand selectivity. In agreement with our mutagenesis data, eszopiclone docking yielded a single model stabilized by several hydrogen bonds. Zolpidem docking yielded three equally populated orientations with few polar interactions, suggesting that unlike eszopiclone, zolpidem relies more on shape recognition of the binding pocket than on specific residue interactions and may explain why zolpidem is highly alpha(1)- and gamma(2)-subunit selective.
|
Displacement of [3H]Ro-151788 from benzodiazepine binding site of GABAA alpha1 S205C beta2gamma2 receptor mutant expressed in HEK293T cells
|
None
|
6.5
nM
|
|
Journal : J. Med. Chem.
Title : Structural requirements for eszopiclone and zolpidem binding to the gamma-aminobutyric acid type-A (GABAA) receptor are different.
Year : 2008
Volume : 51
Issue : 22
First Page : 7243
Last Page : 7252
Authors : Hanson SM, Morlock EV, Satyshur KA, Czajkowski C.
Abstract : The sleep-aids zolpidem and eszopiclone exert their effects by binding to and modulating gamma-aminobutyric acid type-A receptors (GABA(A)Rs), but little is known about the structural requirements for their actions. We made 24 cysteine mutations in the benzodiazepine (BZD) binding site of alpha(1)beta(2)gamma(2) GABA(A)Rs and measured zolpidem, eszopiclone, and BZD-site antagonist binding. Mutations in gamma(2)loop D and alpha(1)loops A and B altered the affinity of all ligands tested, indicating that these loops are important for BZD pocket structural integrity. In contrast, gamma(2)loop E and alpha(1)loop C mutations differentially affected ligand affinity, suggesting that these loops are important for ligand selectivity. In agreement with our mutagenesis data, eszopiclone docking yielded a single model stabilized by several hydrogen bonds. Zolpidem docking yielded three equally populated orientations with few polar interactions, suggesting that unlike eszopiclone, zolpidem relies more on shape recognition of the binding pocket than on specific residue interactions and may explain why zolpidem is highly alpha(1)- and gamma(2)-subunit selective.
|
Displacement of [3H]Ro15-1788 from benzodiazepine binding site of GABAA alpha-1 T206C beta2gamma2 receptor mutant expressed in HEK293T cells
|
None
|
2.1
nM
|
|
Journal : J. Med. Chem.
Title : Structural requirements for eszopiclone and zolpidem binding to the gamma-aminobutyric acid type-A (GABAA) receptor are different.
Year : 2008
Volume : 51
Issue : 22
First Page : 7243
Last Page : 7252
Authors : Hanson SM, Morlock EV, Satyshur KA, Czajkowski C.
Abstract : The sleep-aids zolpidem and eszopiclone exert their effects by binding to and modulating gamma-aminobutyric acid type-A receptors (GABA(A)Rs), but little is known about the structural requirements for their actions. We made 24 cysteine mutations in the benzodiazepine (BZD) binding site of alpha(1)beta(2)gamma(2) GABA(A)Rs and measured zolpidem, eszopiclone, and BZD-site antagonist binding. Mutations in gamma(2)loop D and alpha(1)loops A and B altered the affinity of all ligands tested, indicating that these loops are important for BZD pocket structural integrity. In contrast, gamma(2)loop E and alpha(1)loop C mutations differentially affected ligand affinity, suggesting that these loops are important for ligand selectivity. In agreement with our mutagenesis data, eszopiclone docking yielded a single model stabilized by several hydrogen bonds. Zolpidem docking yielded three equally populated orientations with few polar interactions, suggesting that unlike eszopiclone, zolpidem relies more on shape recognition of the binding pocket than on specific residue interactions and may explain why zolpidem is highly alpha(1)- and gamma(2)-subunit selective.
|
Displacement of [3H]Ro15-1788 from benzodiazepine binding site of GABAA alpha-1 V211C beta2gamma2 receptor mutant expressed in HEK293T cells
|
None
|
4.1
nM
|
|
Journal : J. Med. Chem.
Title : Structural requirements for eszopiclone and zolpidem binding to the gamma-aminobutyric acid type-A (GABAA) receptor are different.
Year : 2008
Volume : 51
Issue : 22
First Page : 7243
Last Page : 7252
Authors : Hanson SM, Morlock EV, Satyshur KA, Czajkowski C.
Abstract : The sleep-aids zolpidem and eszopiclone exert their effects by binding to and modulating gamma-aminobutyric acid type-A receptors (GABA(A)Rs), but little is known about the structural requirements for their actions. We made 24 cysteine mutations in the benzodiazepine (BZD) binding site of alpha(1)beta(2)gamma(2) GABA(A)Rs and measured zolpidem, eszopiclone, and BZD-site antagonist binding. Mutations in gamma(2)loop D and alpha(1)loops A and B altered the affinity of all ligands tested, indicating that these loops are important for BZD pocket structural integrity. In contrast, gamma(2)loop E and alpha(1)loop C mutations differentially affected ligand affinity, suggesting that these loops are important for ligand selectivity. In agreement with our mutagenesis data, eszopiclone docking yielded a single model stabilized by several hydrogen bonds. Zolpidem docking yielded three equally populated orientations with few polar interactions, suggesting that unlike eszopiclone, zolpidem relies more on shape recognition of the binding pocket than on specific residue interactions and may explain why zolpidem is highly alpha(1)- and gamma(2)-subunit selective.
|
Displacement of [3H]Ro-151788 from benzodiazepine binding site of GABAA alpha-3-beta-2-gamma-2 receptor expressed in HEK293T cells
|
None
|
8.1
nM
|
|
Journal : J. Med. Chem.
Title : Structural requirements for eszopiclone and zolpidem binding to the gamma-aminobutyric acid type-A (GABAA) receptor are different.
Year : 2008
Volume : 51
Issue : 22
First Page : 7243
Last Page : 7252
Authors : Hanson SM, Morlock EV, Satyshur KA, Czajkowski C.
Abstract : The sleep-aids zolpidem and eszopiclone exert their effects by binding to and modulating gamma-aminobutyric acid type-A receptors (GABA(A)Rs), but little is known about the structural requirements for their actions. We made 24 cysteine mutations in the benzodiazepine (BZD) binding site of alpha(1)beta(2)gamma(2) GABA(A)Rs and measured zolpidem, eszopiclone, and BZD-site antagonist binding. Mutations in gamma(2)loop D and alpha(1)loops A and B altered the affinity of all ligands tested, indicating that these loops are important for BZD pocket structural integrity. In contrast, gamma(2)loop E and alpha(1)loop C mutations differentially affected ligand affinity, suggesting that these loops are important for ligand selectivity. In agreement with our mutagenesis data, eszopiclone docking yielded a single model stabilized by several hydrogen bonds. Zolpidem docking yielded three equally populated orientations with few polar interactions, suggesting that unlike eszopiclone, zolpidem relies more on shape recognition of the binding pocket than on specific residue interactions and may explain why zolpidem is highly alpha(1)- and gamma(2)-subunit selective.
|
Activity at rat GABAA alpha-1H101Cbeta-2-gamma-2 mutant receptor expressed in xenopus oocytes assessed as change in GABA-induced current amplitude at 1 uM after 1 min exposure to GABA by two electrode voltage clamp method
|
Rattus norvegicus
|
22.0
%
|
|
Journal : J. Biol. Chem.
Title : Proximity-accelerated chemical coupling reaction in the benzodiazepine-binding site of gamma-aminobutyric acid type A receptors: superposition of different allosteric modulators.
Year : 2007
Volume : 282
Issue : 36
First Page : 26316
Last Page : 26325
Authors : Tan KR, Gonthier A, Baur R, Ernst M, Goeldner M, Sigel E.
Abstract : Benzodiazepines are widely used drugs. They exert sedative/hypnotic, anxiolytic, muscle relaxant, and anticonvulsant effects and act through a specific high affinity binding site on the major inhibitory neurotransmitter receptor, the gamma-aminobutyric acid type A (GABA(A)) receptor. Ligands of the benzodiazepine-binding site are classified into three groups depending on their mode of action: positive and negative allosteric modulators and antagonists. To rationally design ligands of the benzodiazepine site in different isoforms of the GABA(A) receptor, we need to understand the relative positioning and overlap of modulators of different allosteric properties. To solve these questions, we used a proximity-accelerated irreversible chemical coupling reaction. GABA(A) receptor residues thought to reside in the benzodiazepine-binding site were individually mutated to cysteine and combined with a cysteine-reactive benzodiazepine site ligand. Direct apposition of reaction partners is expected to lead to a covalent reaction. We describe here such a reaction of predominantly alpha(1)H101C and also three other mutants (alpha(1)G157C, alpha(1)V202C, and alpha(1)V211C) with an Imid-NCS derivative in which a reactive isothiocyanate group (-NCS) replaces the azide group (-N(3)) in the partial negative allosteric modulator Ro15-4513. Our results show four contact points of imidazobenzodiazepines with the receptor, alpha(1)H101C being shared by classical benzodiazepines. Taken together with previous data, a similar orientation of these ligands within the benzodiazepine-binding pocket may be proposed.
|
Activity at rat wild type GABAA alpha-1H101Cbeta-2-gamma-2 mutant receptor expressed in xenopus oocytes assessed as GABA-elicited response by two electrode voltage clamp method relative to control
|
Rattus norvegicus
|
30.0
nM
|
|
Journal : J. Biol. Chem.
Title : Proximity-accelerated chemical coupling reaction in the benzodiazepine-binding site of gamma-aminobutyric acid type A receptors: superposition of different allosteric modulators.
Year : 2007
Volume : 282
Issue : 36
First Page : 26316
Last Page : 26325
Authors : Tan KR, Gonthier A, Baur R, Ernst M, Goeldner M, Sigel E.
Abstract : Benzodiazepines are widely used drugs. They exert sedative/hypnotic, anxiolytic, muscle relaxant, and anticonvulsant effects and act through a specific high affinity binding site on the major inhibitory neurotransmitter receptor, the gamma-aminobutyric acid type A (GABA(A)) receptor. Ligands of the benzodiazepine-binding site are classified into three groups depending on their mode of action: positive and negative allosteric modulators and antagonists. To rationally design ligands of the benzodiazepine site in different isoforms of the GABA(A) receptor, we need to understand the relative positioning and overlap of modulators of different allosteric properties. To solve these questions, we used a proximity-accelerated irreversible chemical coupling reaction. GABA(A) receptor residues thought to reside in the benzodiazepine-binding site were individually mutated to cysteine and combined with a cysteine-reactive benzodiazepine site ligand. Direct apposition of reaction partners is expected to lead to a covalent reaction. We describe here such a reaction of predominantly alpha(1)H101C and also three other mutants (alpha(1)G157C, alpha(1)V202C, and alpha(1)V211C) with an Imid-NCS derivative in which a reactive isothiocyanate group (-NCS) replaces the azide group (-N(3)) in the partial negative allosteric modulator Ro15-4513. Our results show four contact points of imidazobenzodiazepines with the receptor, alpha(1)H101C being shared by classical benzodiazepines. Taken together with previous data, a similar orientation of these ligands within the benzodiazepine-binding pocket may be proposed.
|
Displacement of [3H]flumazenil from CBR in bovine cortical membrane
|
Bos taurus
|
1.9
nM
|
|
Journal : J. Med. Chem.
Title : Ethyl 8-fluoro-6-(3-nitrophenyl)-4H-imidazo[1,5-a][1,4]benzodiazepine-3-carboxylate as novel, highly potent, and safe antianxiety agent.
Year : 2008
Volume : 51
Issue : 15
First Page : 4730
Last Page : 4743
Authors : Anzini M, Braile C, Valenti S, Cappelli A, Vomero S, Marinelli L, Limongelli V, Novellino E, Betti L, Giannaccini G, Lucacchini A, Ghelardini C, Norcini M, Makovec F, Giorgi G, Ian Fryer R.
Abstract : Ethyl 8-fluoro-6-(4-nitrophenyl)- and ethyl 8-fluoro-6-(3-nitrophenyl)-4 H-imidazo[1,5-a][1,4]benzodiazepine 3-carboxylate 6 and 7 were synthesized as central benzodiazepine receptor (CBR) ligands and tested for their ability to displace [(3)H]flumazenil from bovine and human cortical brain membranes. Both compounds showed high affinity for bovine and human CBR. In particular, compound 7 emerged as the most interesting compound, having a partial agonist profile in vitro while possessing useful activity in various animal models of anxiety. In accordance with its partial agonist profile, compound 7 was devoid of typical benzodiazepine side effects. The homology model of the GABA A receptor developed by Cromer et al. was used to assess the binding modes of ligands 6 and 7. From our docking results, the partial agonist activity elicited by compound 7 is likely to be due to the 3'-nitro substituent, which is in the appropriate position to interact with Thr193 of the gamma 2-subunit by means of a hydrogen bond.
|
Displacement of [3H]flumazenil from CBR in human cortical membrane
|
Homo sapiens
|
2.1
nM
|
|
Journal : J. Med. Chem.
Title : Ethyl 8-fluoro-6-(3-nitrophenyl)-4H-imidazo[1,5-a][1,4]benzodiazepine-3-carboxylate as novel, highly potent, and safe antianxiety agent.
Year : 2008
Volume : 51
Issue : 15
First Page : 4730
Last Page : 4743
Authors : Anzini M, Braile C, Valenti S, Cappelli A, Vomero S, Marinelli L, Limongelli V, Novellino E, Betti L, Giannaccini G, Lucacchini A, Ghelardini C, Norcini M, Makovec F, Giorgi G, Ian Fryer R.
Abstract : Ethyl 8-fluoro-6-(4-nitrophenyl)- and ethyl 8-fluoro-6-(3-nitrophenyl)-4 H-imidazo[1,5-a][1,4]benzodiazepine 3-carboxylate 6 and 7 were synthesized as central benzodiazepine receptor (CBR) ligands and tested for their ability to displace [(3)H]flumazenil from bovine and human cortical brain membranes. Both compounds showed high affinity for bovine and human CBR. In particular, compound 7 emerged as the most interesting compound, having a partial agonist profile in vitro while possessing useful activity in various animal models of anxiety. In accordance with its partial agonist profile, compound 7 was devoid of typical benzodiazepine side effects. The homology model of the GABA A receptor developed by Cromer et al. was used to assess the binding modes of ligands 6 and 7. From our docking results, the partial agonist activity elicited by compound 7 is likely to be due to the 3'-nitro substituent, which is in the appropriate position to interact with Thr193 of the gamma 2-subunit by means of a hydrogen bond.
|
DRUGMATRIX: GABAA, Flunitrazepam, Central radioligand binding (ligand: [3H] Flunitrazepam)
|
Rattus norvegicus
|
3.867
nM
|
|
DRUGMATRIX: GABAA, Flunitrazepam, Central radioligand binding (ligand: [3H] Flunitrazepam)
|
Rattus norvegicus
|
3.151
nM
|
|
Title : DrugMatrix in vitro pharmacology data
Authors : Scott S. Auerbach, DrugMatrix¨ and ToxFX¨ Coordinator National Toxicology Program
Abstract : The DrugMatrix Pharmacology data is a subset of the data freely available from the National Toxicology Program. For more details see:https://ntp.niehs.nih.gov/drugmatrix/index.html
|
Displacement of [3H]flumazenil from central benzodiazepine receptor in rat cerebral cortex membranes at 10 uM after 90 mins by competitive binding assay
|
Rattus norvegicus
|
0.0
%
|
|
Journal : J. Med. Chem.
Title : Synthesis and biological evaluation of 4-phenylquinazoline-2-carboxamides designed as a novel class of potent ligands of the translocator protein.
Year : 2012
Volume : 55
Issue : 9
First Page : 4506
Last Page : 4510
Authors : Castellano S, Taliani S, Milite C, Pugliesi I, Da Pozzo E, Rizzetto E, Bendinelli S, Costa B, Cosconati S, Greco G, Novellino E, Sbardella G, Stefancich G, Martini C, Da Settimo F.
Abstract : A series of novel 4-phenylquinazoline-2-carboxamides (1-58) were designed as aza-isosters of PK11195, the well-known 18 kDa translocator protein (TSPO) reference ligand, and synthesized by means of a very simple and efficient procedure. A number of these derivatives bind to the TSPO with K(i) values in the nanomolar/subnanomolar range, show selectivity toward the central benzodiazepine receptor (BzR) and exhibit structure-affinity relationships consistent with a previously published pharmacophore/topological model of ligand-TSPO interaction.
|
Displacement of [3H]flumazenil from central benzodiazepine receptor in bovine cortical membrane after 90 mins by beta liquid scintillation counting
|
Bos taurus
|
1.9
nM
|
|
Journal : J. Med. Chem.
Title : New insight into the central benzodiazepine receptor-ligand interactions: design, synthesis, biological evaluation, and molecular modeling of 3-substituted 6-phenyl-4H-imidazo[1,5-a][1,4]benzodiazepines and related compounds.
Year : 2011
Volume : 54
Issue : 16
First Page : 5694
Last Page : 5711
Authors : Anzini M, Valenti S, Braile C, Cappelli A, Vomero S, Alcaro S, Ortuso F, Marinelli L, Limongelli V, Novellino E, Betti L, Giannaccini G, Lucacchini A, Daniele S, Martini C, Ghelardini C, Di Cesare Mannelli L, Giorgi G, Mascia MP, Biggio G.
Abstract : 3-Substituted 6-phenyl-4H-imidazo[1,5-a][1,4]benzodiazepines and related compounds were synthesized as central benzodiazepine receptor (CBR) ligands. Most of the compounds showed high affinity for bovine and human CBR, their K(i) values spanning from the low nanomolar to the submicromolar range. In particular, imidazoester 5f was able to promote a massive flow of (36)Cl(-) in rat cerebrocortical synaptoneurosomes overlapping its efficacy profile with that of a typical full agonist. Compound 5f was then examined in mice for its pharmacological effects where it proved to be a safe anxiolytic agent devoid of the unpleasant myorelaxant and amnesic effects of the classical 1,4-benzodiazepines. Moreover, the selectivity of some selected compounds has been assessed in recombinant α(1)β(2)γ(2)L, α(2)β(1)γ(2)L, and α(5)β(2)γ(2)L human GABA(A) receptors. Finally, some compounds were submitted to molecular docking calculations along with molecular dynamics simulations in the Cromer's GABA(A) homology model.
|
Displacement of [3H]flumazenil from central benzodiazepine receptor in human cortical membrane after 90 mins by beta liquid scintillation counting
|
Homo sapiens
|
2.1
nM
|
|
Journal : J. Med. Chem.
Title : New insight into the central benzodiazepine receptor-ligand interactions: design, synthesis, biological evaluation, and molecular modeling of 3-substituted 6-phenyl-4H-imidazo[1,5-a][1,4]benzodiazepines and related compounds.
Year : 2011
Volume : 54
Issue : 16
First Page : 5694
Last Page : 5711
Authors : Anzini M, Valenti S, Braile C, Cappelli A, Vomero S, Alcaro S, Ortuso F, Marinelli L, Limongelli V, Novellino E, Betti L, Giannaccini G, Lucacchini A, Daniele S, Martini C, Ghelardini C, Di Cesare Mannelli L, Giorgi G, Mascia MP, Biggio G.
Abstract : 3-Substituted 6-phenyl-4H-imidazo[1,5-a][1,4]benzodiazepines and related compounds were synthesized as central benzodiazepine receptor (CBR) ligands. Most of the compounds showed high affinity for bovine and human CBR, their K(i) values spanning from the low nanomolar to the submicromolar range. In particular, imidazoester 5f was able to promote a massive flow of (36)Cl(-) in rat cerebrocortical synaptoneurosomes overlapping its efficacy profile with that of a typical full agonist. Compound 5f was then examined in mice for its pharmacological effects where it proved to be a safe anxiolytic agent devoid of the unpleasant myorelaxant and amnesic effects of the classical 1,4-benzodiazepines. Moreover, the selectivity of some selected compounds has been assessed in recombinant α(1)β(2)γ(2)L, α(2)β(1)γ(2)L, and α(5)β(2)γ(2)L human GABA(A) receptors. Finally, some compounds were submitted to molecular docking calculations along with molecular dynamics simulations in the Cromer's GABA(A) homology model.
|
Displacement of [3F]FMZ from Wistar rat cerebellum GABAA receptor by competitive radioligand assay
|
Rattus norvegicus
|
1.3
nM
|
|
Journal : Bioorg. Med. Chem. Lett.
Title : The development of potential new fluorine-18 labelled radiotracers for imaging the GABA(A) receptor.
Year : 2013
Volume : 23
Issue : 3
First Page : 821
Last Page : 826
Authors : Jackson A, Guilbert BB, Plant SD, Goggi J, Battle MR, Woodcraft JL, Gaeta A, Jones CL, Bouvet DR, Jones PA, O'Shea DM, Zheng PH, Brown SL, Ewan AL, Trigg W.
Abstract : Positron emission tomography (PET) using the tracer [(11)C]Flumazenil has shown changes in the distribution and expression of the GABA(A) receptor in a range of neurological conditions and injury states. We aim to develop a fluorine-18 labelled PET agent with comparable properties to [(11)C]Flumazenil. In this study we make a direct comparison between the currently known fluorine-18 labelled GABA(A) radiotracers and novel imidazobenzodiazepine ligands. A focussed library of novel compound was designed and synthesised where the fluorine containing moiety and the position of attachment is varied. The in vitro affinity of twenty-two compounds for the GABA(A) receptor was measured. Compounds containing a fluoroalkyl amide or a longer chain ester group were eliminated due to low potency. The fluorine-18 radiochemistry of one compound from each structural type was assessed to confirm that an automated radiosynthesis in good yield was feasible. Eleven of the novel compounds assessed appeared suitable for in vivo assessment as PET tracers.
|
Binding affinity to human GABAA alpha3beta2gamma2 expressed in thymidine kinase-deficient L cells
|
Homo sapiens
|
0.45
nM
|
|
Journal : J. Med. Chem.
Title : Ion channels as therapeutic targets: a drug discovery perspective.
Year : 2013
Volume : 56
Issue : 3
First Page : 593
Last Page : 624
Authors : Bagal SK, Brown AD, Cox PJ, Omoto K, Owen RM, Pryde DC, Sidders B, Skerratt SE, Stevens EB, Storer RI, Swain NA.
Abstract : Ion channels are membrane proteins expressed in almost all living cells. The sequencing of the human genome has identified more than 400 putative ion channels, but only a fraction of these have been cloned and functionally tested. The widespread tissue distribution of ion channels, coupled with the plethora of physiological consequences of their opening and closing, makes ion-channel-targeted drug discovery highly compelling. However, despite some important drugs in clinical use today, as a class, ion channels remain underexploited in drug discovery and many existing drugs are poorly selective with significant toxicities or suboptimal efficacy. This Perspective seeks to review the ion channel family, its structural and functional features, and the diseases that are known to be modulated by members of the family. In particular, we will explore the structure and properties of known ligands and consider the future prospects for drug discovery in this challenging but high potential area.
|
Displacement of [3H]-flumazenil from central-type benzodiazepine receptor in bovine cortical membrane after 90 mins by liquid-phase scintillation beta-counting method
|
Bos taurus
|
1.9
nM
|
|
Journal : J. Med. Chem.
Title : Design, Synthesis, and Biological Evaluation of Imidazo[1,5-a]quinoline as Highly Potent Ligands of Central Benzodiazepine Receptors.
Year : 2016
Volume : 59
Issue : 7
First Page : 3353
Last Page : 3372
Authors : Cappelli A, Anzini M, Castriconi F, Grisci G, Paolino M, Braile C, Valenti S, Giuliani G, Vomero S, Di Capua A, Betti L, Giannaccini G, Lucacchini A, Ghelardini C, Di Cesare Mannelli L, Frosini M, Ricci L, Giorgi G, Mascia MP, Biggio G.
Abstract : A series of imidazo[1,5-a]quinoline derivatives was designed and synthesized as central benzodiazepine receptor (CBR) ligands. Most of the compounds showed high CBR affinity with Ki values within the submicromolar and subnanomolar ranges with interesting modulations in their structure-affinity relationships. In particular, fluoroderivative 7w (Ki = 0.44 nM) resulted in the most potent ligand among the imidazo[1,5-a]quinoline derivatives described so far. Overall, these observations confirmed the assumption concerning the presence of a large though apparently saturable lipophilic pocket in the CBR binding site region interacting with positions 4 and 5 of the imidazo[1,5-a]quinoline nucleus. The in vivo biological characterization revealed that compounds 7a,c,d,l,m,q,r,w show anxiolytic and antiamnestic activities without the unpleasant myorelaxant side effects of the classical 1,4-BDZ. Furthermore, the effect of 7l,q,r, and 8i in lowering lactate dehydrogenase (LDH) release induced by ischemia-like conditions in rat brain slices suggested neuroprotective properties for these imidazo[1,5-a]quinoline derivatives.
|
Displacement of [3H]-flumazenil from central-type benzodiazepine receptor in human cortical membrane after 90 mins by liquid-phase scintillation beta-counting method
|
Homo sapiens
|
2.0
nM
|
|
Journal : J. Med. Chem.
Title : Design, Synthesis, and Biological Evaluation of Imidazo[1,5-a]quinoline as Highly Potent Ligands of Central Benzodiazepine Receptors.
Year : 2016
Volume : 59
Issue : 7
First Page : 3353
Last Page : 3372
Authors : Cappelli A, Anzini M, Castriconi F, Grisci G, Paolino M, Braile C, Valenti S, Giuliani G, Vomero S, Di Capua A, Betti L, Giannaccini G, Lucacchini A, Ghelardini C, Di Cesare Mannelli L, Frosini M, Ricci L, Giorgi G, Mascia MP, Biggio G.
Abstract : A series of imidazo[1,5-a]quinoline derivatives was designed and synthesized as central benzodiazepine receptor (CBR) ligands. Most of the compounds showed high CBR affinity with Ki values within the submicromolar and subnanomolar ranges with interesting modulations in their structure-affinity relationships. In particular, fluoroderivative 7w (Ki = 0.44 nM) resulted in the most potent ligand among the imidazo[1,5-a]quinoline derivatives described so far. Overall, these observations confirmed the assumption concerning the presence of a large though apparently saturable lipophilic pocket in the CBR binding site region interacting with positions 4 and 5 of the imidazo[1,5-a]quinoline nucleus. The in vivo biological characterization revealed that compounds 7a,c,d,l,m,q,r,w show anxiolytic and antiamnestic activities without the unpleasant myorelaxant side effects of the classical 1,4-BDZ. Furthermore, the effect of 7l,q,r, and 8i in lowering lactate dehydrogenase (LDH) release induced by ischemia-like conditions in rat brain slices suggested neuroprotective properties for these imidazo[1,5-a]quinoline derivatives.
|
Antibacterial activity against Staphylococcus aureus MRSA ATCC 43300 (CO-ADD:GP_020); MIC in CAMBH media, using NBS plates, by OD(600)
|
Staphylococcus aureus subsp. aureus
|
-0.36
%
|
|
|
Antibacterial activity against Escherichia coli ATCC 25922 (CO-ADD:GN_001); MIC in CAMBH media using NBS plates, by OD(600)
|
Escherichia coli
|
-2.76
%
|
|
|
Antibacterial activity against Klebsiella pneumoniae MDR ATCC 70063 (CO-ADD:GN_003); MIC in CAMBH media using NBS plates, by OD(600)
|
Klebsiella pneumoniae
|
-2.0
%
|
|
|
Antibacterial activity against Pseudomonas aeruginosa ATCC 27853 (CO-ADD:GN_042); MIC in CAMBH media using NBS plates, by OD(600)
|
Pseudomonas aeruginosa
|
6.15
%
|
|
|
Antibacterial activity against Acinetobacter baumannii ATCC 19606 (CO-ADD:GN_034); MIC in CAMBH media using NBS plates, by OD600
|
Acinetobacter baumannii
|
13.44
%
|
|
|
Antifungal activity against Candida albicans ATCC 90028 (CO-ADD:FG_001); MIC in YNB media using NBS plates, by OD630
|
Candida albicans
|
0.3
%
|
|
|
Antifungal activity against Cryptococcus neoformans H99 ATCC 208821 (CO-ADD:FG_002); MIC in YNB media using NBS plates, by Resazurin OD(600-570)
|
Cryptococcus neoformans
|
-8.54
%
|
|
|
Antiviral activity determined as inhibition of SARS-CoV-2 induced cytotoxicity of Caco-2 cells at 10 uM after 48 hours by high content imaging
|
Homo sapiens
|
-2.01
%
|
|
Title : Identification of inhibitors of SARS-CoV-2 in-vitro cellular toxicity in human (Caco-2) cells using a large scale drug repurposing collection
Year : 2020
Authors : Bernhard Ellinger, Denisa Bojkova, Andrea Zaliani, Jindrich Cinatl, Carsten Claussen, Sandra Westhaus, Jeanette Reinshagen, Maria Kuzikov, Markus Wolf, Gerd Geisslinger, Philip Gribbon, Sandra Ciesek
Abstract : To identify possible candidates for progression towards clinical studies against SARS-CoV-2, we screened a well-defined collection of 5632 compounds including 3488 compounds which have undergone clinical investigations (marketed drugs, phases 1 -3, and withdrawn) across 600 indications. Compounds were screened for their inhibition of viral induced cytotoxicity using the human epithelial colorectal adenocarcinoma cell line Caco-2 and a SARS-CoV-2 isolate. The primary screen of 5632 compounds gave 271 hits. A total of 64 compounds with IC50 <20 µM were identified, including 19 compounds with IC50 < 1 µM. Of this confirmed hit population, 90% have not yet been previously reported as active against SARS-CoV-2 in-vitro cell assays. Some 37 of the actives are launched drugs, 19 are in phases 1-3 and 10 pre-clinical. Several inhibitors were associated with modulation of host pathways including kinase signaling P53 activation, ubiquitin pathways and PDE activity modulation, with long chain acyl transferases were effective viral inhibitors.
|
SARS-CoV-2 3CL-Pro protease inhibition percentage at 20µM by FRET kind of response from peptide substrate
|
Severe acute respiratory syndrome coronavirus 2
|
19.53
%
|
|
SARS-CoV-2 3CL-Pro protease inhibition percentage at 20µM by FRET kind of response from peptide substrate
|
Severe acute respiratory syndrome coronavirus 2
|
12.84
%
|
|
SARS-CoV-2 3CL-Pro protease inhibition percentage at 20µM by FRET kind of response from peptide substrate
|
Severe acute respiratory syndrome coronavirus 2
|
7.66
%
|
|
Title : Identification of inhibitors of SARS-Cov2 M-Pro enzymatic activity using a small molecule repurposing screen
Year : 2020
Authors : Maria Kuzikov, Elisa Costanzi, Jeanette Reinshagen, Francesca Esposito, Laura Vangeel, Markus Wolf, Bernhard Ellinger, Carsten Claussen, Gerd Geisslinger, Angela Corona, Daniela Iaconis, Carmine Talarico, Candida Manelfi, Rolando Cannalire, Giulia Rossetti, Jonas Gossen, Simone Albani, Francesco Musiani, Katja Herzog, Yang Ye, Barbara Giabbai, Nicola Demitri, Dirk Jochmans, Steven De Jonghe, Jasper Rymenants, Vincenzo Summa, Enzo Tramontano, Andrea R. Beccari, Pieter Leyssen, Paola Storici, Johan Neyts, Philip Gribbon, and Andrea Zaliani
Abstract : Compound repurposing is an important strategy being pursued in the identification of effective treatment against the SARS-CoV-2 infection and COVID-19 disease. In this regard, SARS-CoV-2 main protease (M-Pro), also termed 3CL-Pro, is an attractive drug target as it plays a central role in viral replication by processing the viral polyprotein into 11 non-structural proteins. We report the results of a screening campaign involving ca 8.7 K compounds containing marketed drugs, clinical and preclinical candidates, and chemicals regarded as safe in humans. We confirmed previously reported inhibitors of 3CL-Pro, but we have also identified 68 compounds with IC50 lower than 1 uM and 127 compounds with IC50 lower than 5 uM. Profiling showed 67% of confirmed hits were selective (> 5 fold) against other Cys- and Ser- proteases (Chymotrypsin and Cathepsin-L) and MERS 3CL-Pro. Selected compounds were also analysed in their binding characteristics.
|
Antiviral activity determined as inhibition of SARS-CoV-2 induced cytotoxicity of VERO-6 cells at 10 uM after 48 hours exposure to 0.01 MOI SARS CoV-2 virus by high content imaging
|
Chlorocebus sabaeus
|
0.08
%
|
|
Antiviral activity determined as inhibition of SARS-CoV-2 induced cytotoxicity of VERO-6 cells at 10 uM after 48 hours exposure to 0.01 MOI SARS CoV-2 virus by high content imaging
|
Chlorocebus sabaeus
|
0.22
%
|
|
Antiviral activity determined as inhibition of SARS-CoV-2 induced cytotoxicity of VERO-6 cells at 10 uM after 48 hours exposure to 0.01 MOI SARS CoV-2 virus by high content imaging
|
Chlorocebus sabaeus
|
-0.18
%
|
|
Antiviral activity determined as inhibition of SARS-CoV-2 induced cytotoxicity of VERO-6 cells at 10 uM after 48 hours exposure to 0.01 MOI SARS CoV-2 virus by high content imaging
|
Chlorocebus sabaeus
|
0.22
%
|
|
Antiviral activity determined as inhibition of SARS-CoV-2 induced cytotoxicity of VERO-6 cells at 10 uM after 48 hours exposure to 0.01 MOI SARS CoV-2 virus by high content imaging
|
Chlorocebus sabaeus
|
-0.18
%
|
|
Antiviral activity determined as inhibition of SARS-CoV-2 induced cytotoxicity of VERO-6 cells at 10 uM after 48 hours exposure to 0.01 MOI SARS CoV-2 virus by high content imaging
|
Chlorocebus sabaeus
|
0.08
%
|
|
Title : Cytopathic SARS-Cov2 screening on VERO-E6 cells in a large repurposing effort
Year : 2020
Authors : Andrea Zaliani, Laura Vangeel, Jeanette Reinshagen, Daniela Iaconis, Maria Kuzikov, Oliver Keminer, Markus Wolf, Bernhard Ellinger, Francesca Esposito, Angela Corona, Enzo Tramontano, Candida Manelfi, Katja Herzog, Dirk Jochmans, Steven De Jonghe, Winston Chiu, Thibault Francken, Joost Schepers, Caroline Collard, Kayvan Abbasi, Carsten Claussen , Vincenzo Summa, Andrea R. Beccari, Johan Neyts, Philip Gribbon and Pieter Leyssen
Abstract : Worldwide, there are intensive efforts to identify repurposed drugs as potential therapies against SARS-CoV-2 infection and the associated COVID-19 disease. To date, the anti-inflammatory drug dexamethasone and (to a lesser extent) the RNA-polymerase inhibitor remdesivir have been shown to be effective in reducing mortality and patient time to recovery, respectively, in patients. Here, we report the results of a phenotypic screening campaign within an EU-funded project (H2020-EXSCALATE4COV) aimed at extending the repertoire of anti-COVID therapeutics through repurposing of available compounds and highlighting compounds with new mechanisms of action against viral infection. We screened 8702 molecules from different repurposing libraries, to reveal 110 compounds with an anti-cytopathic IC50 < 20 µM. From this group, 18 with a safety index greater than 2 are also marketed drugs, making them suitable for further study as potential therapies against COVID-19. Our result supports the idea that a systematic approach to repurposing is a valid strategy to accelerate the necessary drug discovery process.
|
Displacement of [3H]diazepam from Benzodiazepine receptor in rat cerebral cortex membrane
|
Rattus norvegicus
|
2.3
nM
|
|
Journal : Eur J Med Chem
Title : Design, synthesis and biological evaluation of 7-substituted 4-phenyl-6H-imidazo[1,5-a]thieno[3,2-f] [1,4]diazepines as safe anxiolytic agents.
Year : 2020
Volume : 200
First Page : 112405
Last Page : 112405
Authors : Di Capua A,Reale A,Paolino M,Chemi G,Brogi S,Cappelli A,Giorgi G,Grande F,Di Cesare Mannelli L,Ghelardini C,Matucci R,Garofalo A,Anzini M
Abstract : A series of 4-phenyl-6H-imidazo[1,5-a]thieno[3,2-f][1,4]diazepine-7-carboxylate esters were synthesized and tested as central benzodiazepine receptor (CBR) ligands by the ability to displace [H]flumazenil from rat cortical membranes. All the compounds showed high affinity with IC values ranging from 5.19 to 16.22 nM. In particular, compounds 12b (IC = 8.66 nM) and 12d (IC = 5.19 nM) appeared as the most effective ligands being their affinity values significantly lower than that of diazepam (IC = 18.52 nM). Compounds 12a-f were examined in vivo for their pharmacological effects in mice and five potential benzodiazepine (BDZ) actions were thus taken into consideration: anxiolytic, anticonvulsant, anti-amnesic, hypnotic, and locomotor activities. All the new synthesized compounds were able to induce a significant antianxiety effect and, among them, compound 12f protected pentylenetetrazole (PTZ)-induced convulsions in a dose-dependent manner reaching a 40% effect at 30 mg/kg. In addition, all the compounds were able to significantly prevent the memory impairment evoked by scopolamine, while none of them was able to interfere with pentobarbital-evoked sleep and influence motor coordination. Moreover, title compounds did not affect locomotor and exploratory activity at the same time and doses at which the anti-anxiety effect was observed. Finally, molecular docking simulations were carried out in order to assess the binding mode for compounds 12a-f. The obtained results demonstrated that these compounds bind the BDZ binding site in a similar fashion to flumazenil.
|
Binding affinity to GABBA alpha5 (unknown origin)
|
Homo sapiens
|
0.631
nM
|
|
|
Binding affinity to GABBA alpha1 (unknown origin)
|
Homo sapiens
|
0.7943
nM
|
|
|
Binding affinity to GABBA alpha2 (unknown origin)
|
Homo sapiens
|
0.7943
nM
|
|
|
Binding affinity to GABBA alpha3 (unknown origin)
|
Homo sapiens
|
1.0
nM
|
|
|
Binding affinity to GABBA alpha6 (unknown origin)
|
Homo sapiens
|
158.49
nM
|
|
