|
Binding affinity for central 5-hydroxytryptamine 3 receptor was determined by displacement of [3H]GR-65630
|
None
|
0.59
nM
|
|
Journal : J. Med. Chem.
Title : 5-Hydroxytryptamine (5-HT3) receptor antagonists. 1. Indazole and indolizine-3-carboxylic acid derivatives.
Year : 1990
Volume : 33
Issue : 7
First Page : 1924
Last Page : 1929
Authors : Bermudez J, Fake CS, Joiner GF, Joiner KA, King FD, Miner WD, Sanger GJ.
Abstract : Metoclopramide (1) is a gastric motility stimulant and a weak dopamine and 5-HT3 receptor antagonist. Conformational restriction of the (diethylamino)ethyl side chain of 1 in the form of the azabicyclic tropane gave 3, a very potent gastric motility stimulant and 5-HT3 receptor antagonist but devoid of significant dopamine receptor antagonist properties. Subsequent alteration of the aromatic nucleus led to the identification of indazoles 6a-h, and 1- and 3-indolizines 7b-d and 8, and imidazo[1,5-alpha]pyridines 9 and 10, as potent 5-HT3 receptor antagonists devoid of either dopamine antagonist or gastric motility stimulatory properties. Further conformational restriction of the side chain identified quinuclidine 11 and isoquinuclidine 12 as potent 5-HT3 receptor antagonists which mimic the distorted chair conformation of the tropane with, in the case of 11, the N-methyl group axial. From these series, 6g (BRL 43694) was found to be both potent and selective and has been shown to be a very effective antiemetic agent against cytotoxic drug induced emesis both in the ferret and in man.
|
Compound was evaluated for its in vitro affinity at serotonergic 5-hydroxytryptamine 3 receptor by radioligand binding assay, using [3H]-LY 278584 in rat cerebral cortex membranes.
|
None
|
3.9
nM
|
|
Journal : J. Med. Chem.
Title : Benzimidazole derivatives. 2. Synthesis and structure-activity relationships of new azabicyclic benzimidazole-4-carboxylic acid derivatives with affinity for serotoninergic 5-HT(3) receptors.
Year : 1999
Volume : 42
Issue : 24
First Page : 5020
Last Page : 5028
Authors : López-Rodríguez ML, Benhamú B, Morcillo MJ, Tejada ID, Orensanz L, Alfaro MJ, Martín MI.
Abstract : A new series of azabicyclic benzimidazole-4-carboxamides 2-21 and -carboxylates 22-30 were synthesized and evaluated for binding affinity at serotoninergic 5-HT(3) and 5-HT(4) receptors in the CNS. Most of the synthesized compounds exhibited high or very high affinity for the 5-HT(3) binding site and low to no significant affinity for the 5-HT(4) receptor. SAR observations indicated that a halogen atom at the 6-position and a nitro group at the 7-position of the benzimidazole ring is the best substitution pattern for 5-HT(3) affinity and 5-HT(3)/5-HT(4) selectivity, as well as no substitution in this ring. (S)-(-)-N-(Quinuclidin-3-yl)benzimidazole-4-carboxamides 2, 8, and 14 bound at central 5-HT(3) sites with high affinity (K(i) = 2.6, 0. 13, and 1.7 nM, respectively) and excellent selectivity over serotonin 5-HT(4) and 5-HT(1A) receptors (K(i) > 1000-10000 nM). Furthermore, these new 5-HT(3) receptor ligands were pharmacologically characterized as potent and selective 5-HT(3) antagonists in the isolated guinea pig ileum (pA(2) = 9.6, 9.9, and 9.1, respectively).
|
Displacement of the 5-hydroxytryptamine 3 receptor ligand [3H]GR-65630 from rat brain cortical membranes.
|
None
|
1.72
nM
|
|
Journal : J. Med. Chem.
Title : Development of high-affinity 5-HT3 receptor antagonists. 1. Initial structure-activity relationship of novel benzamides.
Year : 1992
Volume : 35
Issue : 5
First Page : 895
Last Page : 903
Authors : Youssefyeh RD, Campbell HF, Klein S, Airey JE, Darkes P, Powers M, Schnapper M, Neuenschwander K, Fitzpatrick LR, Pendley CE.
Abstract : This report describes the development of novel benzamides which are orally active, highly potent, specific antagonists of 5-HT3 receptors. Described in this first report are the structure-activity relationships that led to novel structures with improved potency and selectivity. From this series of compounds, (S)-28 was identified and selected for further evaluation as a 5-HT3 receptor antagonist. Compared with 5-HT3 antagonists such as GR 38032F, BRL 43694, and metoclopramide, (S)-28 was most active in (a) inhibiting binding to 5-HT3 receptor binding sites in rat entorhinal cortex with an Ki value of 0.19 nM and (b) blocking cisplatin-induced emesis in the ferret with an ED50 value determined to be 9 micrograms/kg po.
|
Compound was evaluated for binding affinity against 5-hydroxytryptamine 3 receptor
|
None
|
0.78
nM
|
|
Journal : J. Med. Chem.
Title : Development of high-affinity 5-HT3 receptor antagonists. Structure-affinity relationships of novel 1,7-annelated indole derivatives.
Year : 1993
Volume : 36
Issue : 23
First Page : 3693
Last Page : 3699
Authors : van Wijngaarden I, Hamminga D, van Hes R, Standaar PJ, Tipker J, Tulp MT, Mol F, Olivier B, de Jonge A.
Abstract : On the basis of the structures of ondansetron and GR 65,630, its ring-opened C-linked methylimidazole analogue, novel 1,7-annelated indole derivatives were synthesized as potential 5-HT3 antagonists. Receptor binding studies show that all compounds display a high affinity for the 5-HT3 receptors. In both series annelation results in compounds being 7 and 4 times more potent than the references ondansetron and GR 65,630, respectively. Similar to ondansetron, the 1,7-annelated indoles show little stereoselectivity. The (-)-isomers are only slightly more potent than the (+)-isomers. The receptor binding profile of l-10-[(2-methyl-1H-imidazol-1-yl)methyl]-5,6,8,9,10,11-hexahydro-4H-pyri do [3,2,1-jk]carbazol-11-one hydrochloride (24b) (INN cilansetron) shows that the compound displays, besides a high affinity for 5-HT3 receptors (Ki = 0.19 nM), a weak affinity for sigma-receptors (Ki = 340 nM), muscarine M1 receptors (Ki = 910 nM), and 5-HT4 receptors (Ki = 960 nM) and no affinity (Ki > or = 5000 nM) for all the other receptor types tested (n = 37). The new compounds fit the proposed necessary chemical template for binding: a heteroaromatic ring system, a coplanar carbonyl group, and a nitrogen center at well-defined distances. The enhanced potency of the annelated 1,7-indole derivatives indicates that the extra ring provides a favorable hydrophobic area for interaction with the 5-HT3 receptor site. In vivo cilansetron is more potent and induces less central side effects than ondansetron. At present cilansetron is in clinical trials.
|
Compound was evaluated for its ability to displace [3H]quipazine binding to 5-hydroxytryptamine 3 receptor sites in NG 108-15.
|
None
|
2.1
nM
|
|
Journal : J. Med. Chem.
Title : 5-HT3 receptor antagonists. 1. New quinoline derivatives.
Year : 1992
Volume : 35
Issue : 26
First Page : 4893
Last Page : 4902
Authors : Hayashi H, Miwa Y, Miki I, Ichikawa S, Yoda N, Ishii A, Kono M, Suzuki F.
Abstract : A series of esters and amides of 1-alkyl-2-oxo-1,2-dihydroquinoline-4- carboxylic acid or 2-alkoxy-quinoline-4-carboxylic acid containing a basic azabicycloalkyl moiety has been synthesized and evaluated for affinity for the [3H]quipazine-labeled 5-HT3 receptors. Most of the esters exhibited 10-fold more potent activity than that of ondansetron (1; Ki = 7.6 nM). Lipophilic substituents at the 1- or 2-position of the quinoline ring enhanced affinity for the receptors. Compounds 21 and 37 showed the highest affinity (Ki = 0.32 and 0.31 nM, respectively) among them. On the other hand, most of the amides showed 100-fold lower affinity than that of the esters. Molecular modeling studies indicated that the carbonyl moiety in 19 (ester) or 31 (amide) was not coplanar to the plane of an aromatic ring (over 20 degrees deviation). Although some of the selected compounds exhibited potent activity in the Bezold-Jarisch (B-J) reflex test, good correlation was not observed between the affinity for the 5-HT3 receptors and the activity in the B-J reflex test (in vivo). From these data, it was suggested that our quinoline derivatives might interact with the 5-HT3 receptors in a different way from that of the reported 5-HT3 receptor antagonists presumably due to the presence of the heterogeneity of the 5-HT3 receptors between brain and heart.
|
Compound was evaluated for its binding affinity for 5-hydroxytryptamine 3 receptor by measuring displacement [3H]GR-65630 in rat cerebral cortex
|
None
|
0.6
nM
|
|
Journal : J. Med. Chem.
Title : 5-HT3 antagonists derived from aminopyridazine-type muscarinic M1 agonists.
Year : 1998
Volume : 41
Issue : 3
First Page : 311
Last Page : 317
Authors : Rival Y, Hoffmann R, Didier B, Rybaltchenko V, Bourguignon JJ, Wermuth CG.
Abstract : A conformational analysis, performed on muscarinic M1 agonists, identified four structural features characteristic of the muscarinic M1 pharmacophore: (i) a protonable basic or quaternary nitrogen acting as a cationic head; (ii) an electronegative dipole usually part of a planar mesomeric ester, amide, or amidine function which can be replaced by an ether (muscarine) or a dioxolane (AF 30); (iii) an intercharge distance of 5 +/- 0.5 A between the cationic head and the electronegative atom of the dipole; (iv) an elevation of 0.5 +/- 0.03 A of the cationic head over the plane containing the electronegative dipole. During a reinvestigation of the conformational behavior of published structures of 5-HT3 antagonists, similar features were observed for the 5-HT3 pharmacophore. However many 5-HT3 antagonists possess additional aromatic planes not present in the muscarinic M1 agonists. These observations brought us to predict the chemical modifications that would change muscarinic M1 agonists into 5-HT3 antagonists. Four of the predicted aminopyridazines were actually synthesized and submitted to testing. The observed IC50 values for 5-HT3 receptor binding ([3H] BRL 43694) ranged from 10 to 425 nM, whereas the affinities for the muscarinic receptor preparations ([3H] pirenzepine) layed over 10,000 nM. In electrophysiological studies the two most active compounds 10 and 13 produced antagonist-like effects on the 5-HT receptor channel complexes responsible for the generation of the rapidly desensitizing ionic currents, and agonist-like effects on those responsible for the slowly desensitizing components.
|
Ability to displace [3H]granisetron specifically bound to 5-hydroxytryptamine 3 receptor in rat cortical membrane
|
None
|
0.35
nM
|
|
Journal : J. Med. Chem.
Title : Novel potent and selective central 5-HT3 receptor ligands provided with different intrinsic efficacy. 1. Mapping the central 5-HT3 receptor binding site by arylpiperazine derivatives.
Year : 1998
Volume : 41
Issue : 5
First Page : 728
Last Page : 741
Authors : Cappelli A, Anzini M, Vomero S, Mennuni L, Makovec F, Doucet E, Hamon M, Bruni G, Romeo MR, Menziani MC, De Benedetti PG, Langer T.
Abstract : Synthesis and pharmacological evaluation of a series of condensed quinoline and pyridine derivatives bearing a N-methylpiperazine moiety attached to the 2-position of the quinoline or pyridine nucleus are described. 5-HT receptor binding studies revealed subnanomolar affinity for the 5-HT3 receptor subtype in some of the compounds under study. The most active compound (5b) displayed a Ki value about 1 order of magnitude higher than that of quipazine along with a higher selectivity. The potential 5-HT3 agonist/antagonist activity of four selected compounds was assessed in vitro on 5-HT3 receptor-dependent [14C]guanidinium uptake in NG 108-15 cells. Compound 5j acted as a 5-HT3 agonist in this assay with an EC50 value close to that reported for quipazine, while 5b was a partial agonist with an EC50 value of about 0.25 nM, and compound 5c possessed antagonist properties with an IC50 value (approximately 8 nM) in the same range as those of previously characterized 5-HT3 receptor antagonists. Qualitative and quantitative structure-affinity relationship studies carried out by making use of theoretical molecular descriptors allowed to elucidate the role of the main pharmacophoric components and to develop a model for the interaction of the 5-HT3 ligands related to quipazine with their receptor.
|
In vitro affinity for 5-hydroxytryptamine 3 (5-HT3) receptor by displacement of [3H]BRL-43694 from rat entorhinal cortex
|
None
|
0.35
nM
|
|
Journal : J. Med. Chem.
Title : Phenylimidazolidin-2-one derivatives as selective 5-HT3 receptor antagonists and refinement of the pharmacophore model for 5-HT3 receptor binding.
Year : 1997
Volume : 40
Issue : 21
First Page : 3369
Last Page : 3380
Authors : Heidempergher F, Pillan A, Pinciroli V, Vaghi F, Arrigoni C, Bolis G, Caccia C, Dho L, McArthur R, Varasi M.
Abstract : A possible bioisosterism between the benzamido and the phenylimidazolidin-2-one moieties has been suggested on the basis of the similarity between the molecular electrostatic potential (MEP) of metoclopramide, a D2 receptor antagonist with weak 5-HT3 receptor antagonist properties, and zetidoline, a D2 receptor antagonist. Starting from this premise, a series of phenylimidazolidin-2-one derivatives bearing a basic azabicycloalkyl or an imidazolylalkyl moiety were synthesized and evaluated for 5-HT3 receptor radioligand binding affinity ([3H]-GR 43,694). In vitro 5-HT3 receptor antagonist activity was tested in the guinea pig ileum assay (GPI). A number of high-affinity ligands were shown to be potent 5-HT3 receptor antagonists in vivo as determined by inhibition of the Bezold--Jarisch reflex in the anesthetized rat. In general, the imidazolylalkyl derivatives were found to be more active than azabicycloalkyls. 1-(3,5-Dichlorophenyl)-3-[(5-methyl-1H-imidazol-4-yl)methyl]imidazoli din-2-one (58), in particular, displayed very high affinity for the 5-HT3 receptor (Ki of 0.038 nM) with a Kb of 5.62 nM in the GPI assay, being more potent than the reference compounds (ondansetron, tropisetron, granisetron, and BRL 46,470) tested. 58 showed an ID50 comparable to that of ondansetron (2.2 micrograms/kg i.v.) in the Bezold--Jarisch reflex. A molecular modeling study based on this structurally novel series of compounds allowed the refinement of previously reported 5-HT3 receptor antagonist pharmacophore models.
|
Inhibitory activity against 5-hydroxytryptamine 3 receptor in rat cortical membranes using [3H]- 1-Methyl-1H-indazole-3-carboxylic acid (8-methyl-8-aza-bicyclo[3.2.1]oct-3-yl)-amide as a radioligand
|
None
|
1.62
nM
|
|
Journal : J. Med. Chem.
Title : Synthesis and biochemical evaluation of tritium-labeled 1-methyl-N-(8-methyl-8-azabicyclo[3.2.1]oct-3-yl)-1H-indazole-3-carboxa mide, a useful radioligand for 5HT3 receptors.
Year : 1990
Volume : 33
Issue : 12
First Page : 3176
Last Page : 3181
Authors : Robertson DW, Bloomquist W, Cohen ML, Reid LR, Schenck K, Wong DT.
Abstract : The advent of potent, highly selective 5HT3 receptor antagonists has stimulated considerable interest in 5HT3 receptor mediated physiology and pharmacology. To permit detailed biochemical studies regarding interaction of the indazole class of serotonin (5HT) antagonists with 5HT3 receptors in multiple tissues, we synthesized 1-methyl-N-(8-methyl-8-azabicyclo[3.2.1]oct-3-yl)-1H-indazole- 3-carboxamide (LY278584, compound 9) in high specific activity, tritium-labeled form. This radioligand was selected as a synthetic target because of its potency as a 5HT3-receptor antagonist, its selectivity for this receptor viz a viz other 5HT-receptor subtypes, and the ability to readily incorporate three tritia via the indazole N-CH3 substituent. Alkylation of N-(8-methyl-8-azabicyclo[3.2.1]oct-3-yl)-1H-indazole-3-carboxamide (8) with sodium hydride and tritium-labeled iodomethane, followed by HPLC purification, resulted in [3H]-9 with a radiochemical purity of 99% and a specific activity of 80.5 Ci/mmol. This radioligand bound with high affinity to a single class of saturable recognition sites in membranes isolated from cerebral cortex of rat brain. The Kd was 0.69 nM and the Bmax was 16.9 fmol/mg of protein. The specific binding was excellent, and accounted for 83-93% of total binding at concentrations of 2 nM or less. The potencies of known 5HT3-receptor antagonists as inhibitors of [3H]-9 binding correlated well with their pharmacological receptor affinities as antagonists of 5HT-induced decreases in heart rate and contraction of guinea pig ileum, suggesting the central recognition site for this radioligand may be extremely similar to or identical with peripheral 5HT3 receptors.
|
Binding affinity towards 5-hydroxytryptamine 3 receptor by displacement of radioligand [3H]GR-65630.
|
None
|
1.72
|
|
Journal : J. Med. Chem.
Title : Development of high-affinity 5-HT3 receptor antagonists. 2. Two novel tricyclic benzamides.
Year : 1992
Volume : 35
Issue : 5
First Page : 903
Last Page : 911
Authors : Youssefyeh RD, Campbell HF, Airey JE, Klein S, Schnapper M, Powers M, Woodward R, Rodriguez W, Golec S, Studt W.
Abstract : Two new classes of potent 5-HT3 agents have been developed and examined as inhibitors of cytotoxic drug induced emesis in the ferret and dog. The absolute configuration of the most active molecules 10 and 18 have been determined by X-ray crystallography. These two compounds are more potent than known 5-HT3 receptor antagonists both in vivo and in vitro in blocking 5-HT3 receptor activation and preventing chemotherapeutic induced emesis. Compared with 5-HT3 antagonists, such as GR 38032F, zacopride, BRL 43694, and ICS 205-930, compound 10 was more potent in (1) inhibiting binding to 5-HT3 receptor binding sites in rat cortex (Ki = 0.17 nM), (2) blocking the von Bezold-Jarisch effect in the rat (lowest effective dose, 1 microgram/kg iv), and (3) inhibiting 5-HT-induced contraction of guinea pig ileum (lowest effective concentration, 10(-9) M). This novel agent was as effective given po as when given iv in reducing cisplatin-induced emetic episodes in the ferret (ED50 = 4 micrograms/kg iv or po). A 1 mg/kg po dose of 10 virtually abolished cisplatin-induced emesis for 10 h in the ferret. However, it was inactive against apomorphine or copper sulfate-induced vomiting. These data, coupled with receptor binding studies of ligands for D2-dopamine, a1, a2, 5-HT1, 5-HT2, and muscarinic receptors demonstrate that 10 is a highly selective 5-HT3 receptor antagonist with remarkable potency in vivo.
|
5-hydroxytryptamine 3 receptor antagonist activity was confirmed by its ability to antagonize 5-HT evoked tachycardia of rabbit isolated heart
|
None
|
0.02512
nM
|
|
Journal : J. Med. Chem.
Title : 5-Hydroxytryptamine (5-HT3) receptor antagonists. 1. Indazole and indolizine-3-carboxylic acid derivatives.
Year : 1990
Volume : 33
Issue : 7
First Page : 1924
Last Page : 1929
Authors : Bermudez J, Fake CS, Joiner GF, Joiner KA, King FD, Miner WD, Sanger GJ.
Abstract : Metoclopramide (1) is a gastric motility stimulant and a weak dopamine and 5-HT3 receptor antagonist. Conformational restriction of the (diethylamino)ethyl side chain of 1 in the form of the azabicyclic tropane gave 3, a very potent gastric motility stimulant and 5-HT3 receptor antagonist but devoid of significant dopamine receptor antagonist properties. Subsequent alteration of the aromatic nucleus led to the identification of indazoles 6a-h, and 1- and 3-indolizines 7b-d and 8, and imidazo[1,5-alpha]pyridines 9 and 10, as potent 5-HT3 receptor antagonists devoid of either dopamine antagonist or gastric motility stimulatory properties. Further conformational restriction of the side chain identified quinuclidine 11 and isoquinuclidine 12 as potent 5-HT3 receptor antagonists which mimic the distorted chair conformation of the tropane with, in the case of 11, the N-methyl group axial. From these series, 6g (BRL 43694) was found to be both potent and selective and has been shown to be a very effective antiemetic agent against cytotoxic drug induced emesis both in the ferret and in man.
|
Binding affinity to 5-hydroxytryptamine 3 receptor entirely in guinea pig ileum
|
Cavia porcellus
|
7.943
nM
|
|
Journal : J. Med. Chem.
Title : Conformation-activity relationship study of 5-HT3 receptor antagonists and a definition of a model for this receptor site.
Year : 1990
Volume : 33
Issue : 6
First Page : 1594
Last Page : 1600
Authors : Hibert MF, Hoffmann R, Miller RC, Carr AA.
Abstract : A conformation-activity relationship study of 5-HT3 receptor antagonists was used to define a pharmacophore and receptor map to qualitatively account for their activity. The design and synthesis of specific keto-amino-indole derivatives that are potent 5-HT3 receptor antagonists gave some support to the model.
|
Binding affinity towards [3H]quipazine labeled 5-hydroxytryptamine 3 receptor sites in HG108-15
|
Cavia porcellus
|
2.1
nM
|
|
Journal : J. Med. Chem.
Title : 5-HT3 receptor antagonists. 3. Quinoline derivatives which may be effective in the therapy of irritable bowel syndrome.
Year : 1993
Volume : 36
Issue : 22
First Page : 3286
Last Page : 3292
Authors : Kishibayashi N, Miwa Y, Hayashi H, Ishii A, Ichikawa S, Nonaka H, Yokoyama T, Suzuki F.
Abstract : A series of quinolinecarboxylic acid derivatives has been previously described as a new class of 5-HT3 receptor antagonists due to deviation of a carbonyl moiety from the place of an aromatic ring in their minimum-energy conformations. These derivatives were evaluated in a wrap-restraint stress-induced defecation model in rats. Reference compounds, ondansetron (1), granisetron (2), and YM060 (4), potently inhibited a stress-induced increase in stools excreted from fed rats (ID50 = 0.27, 0.12, and 0.0052 mg/kg, po, respectively). However, quinoline derivatives exhibited different activities depending on structural class. 4-Hydroxyquinoline-3-carboxylic acid derivatives 5 and 6a possess high affinity for the 5-HT3 receptor (Ki = 6.1 and 1.5 nM, respectively) and exhibit potent activity in the Bezold-Jarisch (B-J) reflex test (ED50 = 0.0017 and 0.000 10 mg/kg, i.v., respectively), but they did not effectively inhibit the increase in fecal pellet output at the dose of 1 mg/kg, po. On the other hand, most of 1-substituted 2-oxoquinoline-4-carboxylates 10 showed less potent activity in the B-J reflex test than 1 or 2 but inhibited restraint stress-induced defecation more potently than 1 or 2. The ID50 value of endo-8-methyl-8- azabicyclo[3.2.1]oct-3-yl 1-isobutyl-2-oxo-1,2-dihydro-4- quinolinecarboxylate 10e was 0.013 mg/kg, po. With respect to the selected compounds 6a and 10e, effects of 5-HT- and thyrotropin-releasing hormone (TRH)-induced defecation, castor oil-induced diarrhea and wrap-restraint stress-induced colonic propulsion in rats were examined. These 5-HT3 receptor antagonists did not effectively inhibit castor oil-induced diarrhea, which has been reported not to be mediated via the 5-HT3 receptor. Although 10e showed 800-fold decreased potency compared with 4 in the B-J reflex test, 10e exhibited activity as potent as 4 in 5-HT- and TRH-induced defecation assays; 10e exhibited 7-fold increased potency compared with 4 in wrap-restraint stress-induced colonic propulsions. From these results, 10e appears to interact selectively with 5-HT3 receptors in the gastrointestinal system and might be effective in the therapy of irritable bowel syndrome (IBS).
|
Evaluated for the antagonistic activity against 5-hydroxytryptamine 3 receptor in isolated guinea pig ileum (GPI)
|
Cavia porcellus
|
15.85
nM
|
|
Journal : Bioorg. Med. Chem. Lett.
Title : Design and synthesis of novel ligands for the 5-HT3 and the 5-HT4 receptor
Year : 1992
Volume : 2
Issue : 5
First Page : 461
Last Page : 466
Authors : Blum E, Buchheit K, Buescher H, Gamse R, Kloeppner E, Meigel H, Papageorgiou C, Waelchli R, Revesz L
|
Binding affinity to 5-hydroxytryptamine 3 receptor of neuronal in the afferent rabbit vagus
|
Oryctolagus cuniculus
|
0.1259
nM
|
|
Journal : J. Med. Chem.
Title : Conformation-activity relationship study of 5-HT3 receptor antagonists and a definition of a model for this receptor site.
Year : 1990
Volume : 33
Issue : 6
First Page : 1594
Last Page : 1600
Authors : Hibert MF, Hoffmann R, Miller RC, Carr AA.
Abstract : A conformation-activity relationship study of 5-HT3 receptor antagonists was used to define a pharmacophore and receptor map to qualitatively account for their activity. The design and synthesis of specific keto-amino-indole derivatives that are potent 5-HT3 receptor antagonists gave some support to the model.
|
Potency at neuronal 5-hydroxytryptamine 3 receptor in the rabbit heart
|
Oryctolagus cuniculus
|
0.01995
nM
|
|
Journal : J. Med. Chem.
Title : Conformation-activity relationship study of 5-HT3 receptor antagonists and a definition of a model for this receptor site.
Year : 1990
Volume : 33
Issue : 6
First Page : 1594
Last Page : 1600
Authors : Hibert MF, Hoffmann R, Miller RC, Carr AA.
Abstract : A conformation-activity relationship study of 5-HT3 receptor antagonists was used to define a pharmacophore and receptor map to qualitatively account for their activity. The design and synthesis of specific keto-amino-indole derivatives that are potent 5-HT3 receptor antagonists gave some support to the model.
|
Evaluated for the antagonistic activity against 5-hydroxytryptamine 3 receptor in isolated perfused rabbit heart (RH)
|
Oryctolagus cuniculus
|
0.07943
nM
|
|
Journal : Bioorg. Med. Chem. Lett.
Title : Design and synthesis of novel ligands for the 5-HT3 and the 5-HT4 receptor
Year : 1992
Volume : 2
Issue : 5
First Page : 461
Last Page : 466
Authors : Blum E, Buchheit K, Buescher H, Gamse R, Kloeppner E, Meigel H, Papageorgiou C, Waelchli R, Revesz L
|
Evaluated for the antagonistic activity against 5-hydroxytryptamine 3 receptor in isolated rabbit vagus nerve (RVN)
|
Oryctolagus cuniculus
|
0.1259
nM
|
|
Journal : Bioorg. Med. Chem. Lett.
Title : Design and synthesis of novel ligands for the 5-HT3 and the 5-HT4 receptor
Year : 1992
Volume : 2
Issue : 5
First Page : 461
Last Page : 466
Authors : Blum E, Buchheit K, Buescher H, Gamse R, Kloeppner E, Meigel H, Papageorgiou C, Waelchli R, Revesz L
|
Inhibition of [3H]granisetron binding to 5-hydroxytryptamine 3 receptor of rat cortical membrane
|
Rattus norvegicus
|
0.35
nM
|
|
Journal : J. Med. Chem.
Title : Novel potent and selective central 5-HT3 receptor ligands provided with different intrinsic efficacy. 2. Molecular basis of the intrinsic efficacy of arylpiperazine derivatives at the central 5-HT3 receptors.
Year : 1999
Volume : 42
Issue : 9
First Page : 1556
Last Page : 1575
Authors : Cappelli A, Anzini M, Vomero S, Canullo L, Mennuni L, Makovec F, Doucet E, Hamon M, Menziani MC, De Benedetti PG, Bruni G, Romeo MR, Giorgi G, Donati A.
Abstract : Novel 5-HT3 receptor ligands were designed and synthesized with the aim of obtaining deeper insight into the molecular basis of the intrinsic efficacy of arylpiperazines interacting with the central 5-HT3 receptor. The newly synthesized compounds and some previously published compounds belonging to the same class of heteroarylpiperazines were tested for their potential ability to displace [3H]granisetron from rat cortical membranes. These 5-HT3 receptor binding studies revealed subnanomolar affinity in several of the compounds under study. The most active ligands were quipazine derivatives bearing a phenyl group in the 4-position and various oxygenated alkyl side chains in the 3-position of the quinoline nucleus. Qualitative and theoretical quantitative structure-affinity relationship studies were carried out, and the interaction model for the 5-HT3 ligands related to quipazine with their receptor, proposed in part 1 of the present work, was updated to incorporate the latest data. The potential 5-HT3 agonist/antagonist activity of 12 selected compounds was assessed in vitro on the 5-HT3 receptor-dependent [14C]guanidinium uptake in NG 108-15 cells. Their intrinsic efficacy ranged from the 5-HT3 full agonist properties of compounds 7a and 8h, i to those of partial agonists 10a,d and antagonists 8b,d,e, and 9c, d,h,i. The comparison between these functional data and those relative to the previously described compounds suggested that in this class of 5-HT3 ligands the intrinsic efficacy is modulated in a rather subtle manner by the steric features of the heteroaryl moiety.
|
Binding affinity against radioligand [3H]quipazine labeled 5-hydroxytryptamine 3 receptor sites in neuroblastoma-glioma (NG108-15) cells.
|
None
|
2.1
nM
|
|
Journal : J. Med. Chem.
Title : 5-HT3 receptor antagonists. 2. 4-Hydroxy-3-quinolinecarboxylic acid derivatives.
Year : 1993
Volume : 36
Issue : 5
First Page : 617
Last Page : 626
Authors : Hayashi H, Miwa Y, Ichikawa S, Yoda N, Miki I, Ishii A, Kono M, Yasuzawa T, Suzuki F.
Abstract : A series of 4-hydroxy-3-quinolinecarboxylic acid derivatives (6) and 4-hydroxy-2-oxo-1,2-dihydro-3-quinolinecarboxylic acid derivatives (7) were designed and synthesized as 5-HT3 receptor antagonists. Molecular modeling studies suggested that the 3-carbonyl moiety in 6 was almost coplanar to the plane of an aromatic ring, but in 7 there was a 30 degrees deviation. 4-Hydroxy substitution in quinoline derivatives enhanced affinity for the 5-HT3 receptors, and endo-N-(8-methyl-8-azabicyclo[3.2.1]oct-3-yl)-4-hydroxy-3- quinolinecarboxamide (6f) exhibited the most potent activity in the Bezold-Jarisch (B-J) reflex test (ED50 = 0.1 micrograms/kg, iv) among quinoline derivatives 6. Although 4-hydroxy-2-oxo-1,2-dihydro-3-quinolinecarboxamide derivatives (7a) exhibited higher affinity (e.g., 7d: Ki = 0.48 nM) for the 5-HT3 receptors than ondansetron (Ki = 7.6 nM) or granisetron (Ki = 2.1 nM), these amides showed less potent activity in the B-J reflex test than the reference compounds. Interestingly, the ester derivatives 7c, 7f, and 7h eliminated affinity for the 5-HT3 receptors. These unusual structure-activity relationships and the deviation of the 3-carbonyl moiety from the plane of an aromatic ring suggest that the active conformation of 7a might be different from the proposed one for the preceding 5-HT3 antagonists. Thus, 6f was chosen for further studies. No receptor binding for a variety of ligands was significantly antagonized by 6f. Comparing the ratios of the ED50 value in the B-J reflex test (rat, iv) with the LD50 value in acute lethal toxicity (mouse, iv), 6f was proved to have a 600-fold wider margin of safety than ondansetron. Compound 6f dose-dependently attenuated both the incidence and frequency of emetic episodes induced by cisplatin in the dog (ED50 = 14 micrograms/kg, iv) more potently than ondansetron (ED50 = 210 micrograms/kg, iv). Compound 6f (KF-20170) is now under further investigation as a drug for treating gastrointestinal disorder.
|
Binding affinity for 5-hydroxytryptamine 3 receptor was determined by measuring displacement of [3H]GR-65630 from rat brain cortices
|
None
|
0.5
nM
|
|
Journal : J. Med. Chem.
Title : Benzoxazole derivatives as novel 5-HT3 receptor partial agonists in the gut.
Year : 1998
Volume : 41
Issue : 16
First Page : 3015
Last Page : 3021
Authors : Sato Y, Yamada M, Yoshida S, Soneda T, Ishikawa M, Nizato T, Suzuki K, Konno F.
Abstract : A series of benzoxazoles with a nitrogen-containing heterocyclic substituent at the 2-position was prepared and evaluated for 5-HT3 partial agonist activity on isolated guinea pig ileum. The nature of the substituent at the 5-position of the benzoxazole ring affected the potency for the 5-HT3 receptor, and the 5-chloro derivatives showed increased potency and lowered intrinsic activity. 5-Chloro-7-methyl-2-(4-methyl-1-homopiperazinyl)benzoxazole (6v) exhibited a high binding affinity in the same range as that of the 5-HT3 antagonist granisetron, and its intrinsic activity was 12% of that of 5-HT. Compound 6v inhibited 5-HT-evoked diarrhea but did not prolong the transition time of glass beads in the normal distal colon even at a dose of 100 times the ED50 for diarrhea inhibition in mice. Compounds of this type are expected to be effective for the treatment of irritable bowel syndrome without the side effect of constipation.
|
Binding affinity to 5-hydroxytryptamine 3 receptor using [3H]GR-65630 as radioligand in rat cortex
|
None
|
0.5888
nM
|
|
Journal : J. Med. Chem.
Title : Conformation-activity relationship study of 5-HT3 receptor antagonists and a definition of a model for this receptor site.
Year : 1990
Volume : 33
Issue : 6
First Page : 1594
Last Page : 1600
Authors : Hibert MF, Hoffmann R, Miller RC, Carr AA.
Abstract : A conformation-activity relationship study of 5-HT3 receptor antagonists was used to define a pharmacophore and receptor map to qualitatively account for their activity. The design and synthesis of specific keto-amino-indole derivatives that are potent 5-HT3 receptor antagonists gave some support to the model.
|
Binding affinity to 5-hydroxytryptamine 3 receptor using [3H]quipazine as radioligand in rat cortex
|
None
|
9.12
nM
|
|
Journal : J. Med. Chem.
Title : Conformation-activity relationship study of 5-HT3 receptor antagonists and a definition of a model for this receptor site.
Year : 1990
Volume : 33
Issue : 6
First Page : 1594
Last Page : 1600
Authors : Hibert MF, Hoffmann R, Miller RC, Carr AA.
Abstract : A conformation-activity relationship study of 5-HT3 receptor antagonists was used to define a pharmacophore and receptor map to qualitatively account for their activity. The design and synthesis of specific keto-amino-indole derivatives that are potent 5-HT3 receptor antagonists gave some support to the model.
|
Displacement of [3H]granisetron from 5-hydroxytryptamine 3 receptor of rat cortex
|
Rattus norvegicus
|
0.2512
nM
|
|
Journal : Bioorg. Med. Chem. Lett.
Title : Synthesis and 5-HT3 receptor antagonist potency of novel (endo) 3,9-diazabicyclo[3.3.1]nonan-7-amino derivatives
Year : 1994
Volume : 4
Issue : 20
First Page : 2373
Last Page : 2376
Authors : Bermudez J, Gaster L, Gregory J, Jerman J, Joiner G, King F, Rahman S
|
In vitro by displacement of [3H]LY-278584 from 5-hydroxytryptamine 3 receptor on rat entorhinal cortex
|
None
|
1.995
nM
|
|
Journal : J. Med. Chem.
Title : New 2-piperazinylbenzimidazole derivatives as 5-HT3 antagonists. Synthesis and pharmacological evaluation.
Year : 1997
Volume : 40
Issue : 4
First Page : 586
Last Page : 593
Authors : Orjales A, Mosquera R, Labeaga L, Rodes R.
Abstract : A series of 2-piperazinylbenzimidazole derivatives were prepared and evaluated as 5-HT3 receptor antagonists. Their 5-HT3 receptor affinities were evaluated by radioligand binding assays, and their abilities to inhibit the 5-HT-induced Bezold-Jarisch reflex in anesthetized rats were determined. Compound 7e (lerisetron, pKi = 9.2) exhibited higher affinity for the 5-HT3 receptor than did tropisetron and granisetron, while compound 7q (pKi = 7.5) had very low affinity for this receptor, showing that substitution on the N1 atom of the benzimidazole ring is essential for affinity and activity. The effect of substitution on the aromatic ring of benzimidazole by several substituents in different positions is also discussed. A strong correlation between the 5-HT3 antagonistic activity of the studied compounds and the position of substitution on the aromatic ring was established. Thus, while the 4-methoxy derivative 7m showed weak affinity for the 5-HT3 receptor (pKi = 6.7), the 7-methoxy derivative 7n exhibited the highest affinity (pKi = 9.4). Compounds 7e and 7n are now under further investigation as drugs for the treatment of nausea and emesis evoked by cancer chemotherapy and radiation.
|
pKi value for inhibition of [3H]LY-278584 binding to 5-hydroxytryptamine 3 receptor
|
Rattus norvegicus
|
1.622
nM
|
|
Journal : J. Med. Chem.
Title : Synthesis and biochemical evaluation of tritium-labeled 1-methyl-N-(8-methyl-8-azabicyclo[3.2.1]oct-3-yl)-1H-indazole-3-carboxa mide, a useful radioligand for 5HT3 receptors.
Year : 1990
Volume : 33
Issue : 12
First Page : 3176
Last Page : 3181
Authors : Robertson DW, Bloomquist W, Cohen ML, Reid LR, Schenck K, Wong DT.
Abstract : The advent of potent, highly selective 5HT3 receptor antagonists has stimulated considerable interest in 5HT3 receptor mediated physiology and pharmacology. To permit detailed biochemical studies regarding interaction of the indazole class of serotonin (5HT) antagonists with 5HT3 receptors in multiple tissues, we synthesized 1-methyl-N-(8-methyl-8-azabicyclo[3.2.1]oct-3-yl)-1H-indazole- 3-carboxamide (LY278584, compound 9) in high specific activity, tritium-labeled form. This radioligand was selected as a synthetic target because of its potency as a 5HT3-receptor antagonist, its selectivity for this receptor viz a viz other 5HT-receptor subtypes, and the ability to readily incorporate three tritia via the indazole N-CH3 substituent. Alkylation of N-(8-methyl-8-azabicyclo[3.2.1]oct-3-yl)-1H-indazole-3-carboxamide (8) with sodium hydride and tritium-labeled iodomethane, followed by HPLC purification, resulted in [3H]-9 with a radiochemical purity of 99% and a specific activity of 80.5 Ci/mmol. This radioligand bound with high affinity to a single class of saturable recognition sites in membranes isolated from cerebral cortex of rat brain. The Kd was 0.69 nM and the Bmax was 16.9 fmol/mg of protein. The specific binding was excellent, and accounted for 83-93% of total binding at concentrations of 2 nM or less. The potencies of known 5HT3-receptor antagonists as inhibitors of [3H]-9 binding correlated well with their pharmacological receptor affinities as antagonists of 5HT-induced decreases in heart rate and contraction of guinea pig ileum, suggesting the central recognition site for this radioligand may be extremely similar to or identical with peripheral 5HT3 receptors.
|
Binding affinity against 5-hydroxytryptamine 3 (5-HT3) receptor in rat brain cortical membranes using radioligand [3H]quipazine
|
None
|
0.7943
nM
|
|
Journal : J. Med. Chem.
Title : 2-(Quinuclidin-3-yl)pyrido[4,3-b]indol-1-ones and isoquinolin-1-ones. Potent conformationally restricted 5-HT3 receptor antagonists.
Year : 1993
Volume : 36
Issue : 18
First Page : 2645
Last Page : 2657
Authors : Clark RD, Miller AB, Berger J, Repke DB, Weinhardt KK, Kowalczyk BA, Eglen RM, Bonhaus DW, Lee CH, Michel AD.
Abstract : Several series of N-(quinuclidin-3-yl)aryl and heteroaryl-fused pyridones were synthesized and evaluated for 5-HT3 receptor affinity. In the heteroaryl series, 2-(quinuclidin-3-yl)tetrahydropyrido-[4,3-b]indol-1-one (8a) and the 4,5-alkano-bridged analogues (14 and 15) displayed high 5-HT3 receptor affinity with pKi values > 9. The (3S)-quinuclidinyl isomers had > 10 fold higher affinity than the (3R)-isomers. In a series of 2-quinuclidin-3-yl)isoquinolin-1-ones, derivatives substituted with small lipophilic groups (25b-e) and with 4,5-alkano-bridges (34-36) also displayed high affinity. In particular, the hexahydro-1H-benz[de]isoquinolinone (S,S)-37 was the highest affinity 5-HT3 receptor ligand prepared (pKi 10.4). A number of the high affinity ligands were shown to be potent 5-HT3 receptor antagonists in vivo as determined by inhibition of the B-J reflex in the anesthetized rat. Again, (S,S)-37 was the most active agent tested (ID50 0.02 microgram/kg i.v.), and this compound was also potent in blocking cisplatin-induced emesis in both the ferret and the dog. Computer modeling studies were performed, and previously reported 5-HT3 receptor antagonist pharmacophore models were refined to include a key lipophilic binding domain.
|
In vitro Binding affinity towards 5-hydroxytryptamine 3 receptor was determined
|
None
|
24.0
nM
|
|
Journal : Bioorg. Med. Chem. Lett.
Title : The 5-HT3 antagonist tropisetron (ICS 205-930) is a potent and selective alpha7 nicotinic receptor partial agonist.
Year : 2001
Volume : 11
Issue : 3
First Page : 319
Last Page : 321
Authors : Macor JE, Gurley D, Lanthorn T, Loch J, Mack RA, Mullen G, Tran O, Wright N, Gordon JC.
Abstract : The 5-HT3 receptor antagonist tropisetron (ICS 205-930) was found to be a potent and selective partial agonist at alpha7 nicotinic receptors. Two other 5-HT3 receptor antagonists, ondansetron and LY-278,584, were found to lack high affinity at the alpha7 nicotinic receptor. Quinuclidine analogues (1 and 2) of tropisetron were also found to be potent and selective partial agonists at alpha7 nicotinic receptors.
|
Single-point analysis using 5(10e-9) M concentration of the antagonist (pA2= -log([B]/concentration ratio-1); [B] =concentration of the antagonist).
|
Cavia porcellus
|
0.631
nM
|
|
Journal : J. Med. Chem.
Title : Benzimidazole derivatives. 2. Synthesis and structure-activity relationships of new azabicyclic benzimidazole-4-carboxylic acid derivatives with affinity for serotoninergic 5-HT(3) receptors.
Year : 1999
Volume : 42
Issue : 24
First Page : 5020
Last Page : 5028
Authors : López-Rodríguez ML, Benhamú B, Morcillo MJ, Tejada ID, Orensanz L, Alfaro MJ, Martín MI.
Abstract : A new series of azabicyclic benzimidazole-4-carboxamides 2-21 and -carboxylates 22-30 were synthesized and evaluated for binding affinity at serotoninergic 5-HT(3) and 5-HT(4) receptors in the CNS. Most of the synthesized compounds exhibited high or very high affinity for the 5-HT(3) binding site and low to no significant affinity for the 5-HT(4) receptor. SAR observations indicated that a halogen atom at the 6-position and a nitro group at the 7-position of the benzimidazole ring is the best substitution pattern for 5-HT(3) affinity and 5-HT(3)/5-HT(4) selectivity, as well as no substitution in this ring. (S)-(-)-N-(Quinuclidin-3-yl)benzimidazole-4-carboxamides 2, 8, and 14 bound at central 5-HT(3) sites with high affinity (K(i) = 2.6, 0. 13, and 1.7 nM, respectively) and excellent selectivity over serotonin 5-HT(4) and 5-HT(1A) receptors (K(i) > 1000-10000 nM). Furthermore, these new 5-HT(3) receptor ligands were pharmacologically characterized as potent and selective 5-HT(3) antagonists in the isolated guinea pig ileum (pA(2) = 9.6, 9.9, and 9.1, respectively).
|
Quantitative effect on the [14C]guanidinium accumulation in NG 108-15 cells.
|
None
|
2.8
nM
|
|
Journal : J. Med. Chem.
Title : Novel potent and selective central 5-HT3 receptor ligands provided with different intrinsic efficacy. 2. Molecular basis of the intrinsic efficacy of arylpiperazine derivatives at the central 5-HT3 receptors.
Year : 1999
Volume : 42
Issue : 9
First Page : 1556
Last Page : 1575
Authors : Cappelli A, Anzini M, Vomero S, Canullo L, Mennuni L, Makovec F, Doucet E, Hamon M, Menziani MC, De Benedetti PG, Bruni G, Romeo MR, Giorgi G, Donati A.
Abstract : Novel 5-HT3 receptor ligands were designed and synthesized with the aim of obtaining deeper insight into the molecular basis of the intrinsic efficacy of arylpiperazines interacting with the central 5-HT3 receptor. The newly synthesized compounds and some previously published compounds belonging to the same class of heteroarylpiperazines were tested for their potential ability to displace [3H]granisetron from rat cortical membranes. These 5-HT3 receptor binding studies revealed subnanomolar affinity in several of the compounds under study. The most active ligands were quipazine derivatives bearing a phenyl group in the 4-position and various oxygenated alkyl side chains in the 3-position of the quinoline nucleus. Qualitative and theoretical quantitative structure-affinity relationship studies were carried out, and the interaction model for the 5-HT3 ligands related to quipazine with their receptor, proposed in part 1 of the present work, was updated to incorporate the latest data. The potential 5-HT3 agonist/antagonist activity of 12 selected compounds was assessed in vitro on the 5-HT3 receptor-dependent [14C]guanidinium uptake in NG 108-15 cells. Their intrinsic efficacy ranged from the 5-HT3 full agonist properties of compounds 7a and 8h, i to those of partial agonists 10a,d and antagonists 8b,d,e, and 9c, d,h,i. The comparison between these functional data and those relative to the previously described compounds suggested that in this class of 5-HT3 ligands the intrinsic efficacy is modulated in a rather subtle manner by the steric features of the heteroaryl moiety.
|
Inhibition of the von Bezold-Jarisch reflex bradycardia induced by an iv bolus injection of 5-HT
|
Rattus norvegicus
|
0.7
ug kg-1
|
|
Journal : Bioorg. Med. Chem. Lett.
Title : Synthesis and 5-HT3 receptor antagonist potency of novel (endo) 3,9-diazabicyclo[3.3.1]nonan-7-amino derivatives
Year : 1994
Volume : 4
Issue : 20
First Page : 2373
Last Page : 2376
Authors : Bermudez J, Gaster L, Gregory J, Jerman J, Joiner G, King F, Rahman S
|
Antagonist activity (100 mg/Kg) for the Bezold Jarisch reflex evoked by 30(mg/Kg) of 5-HT in ethylurethane anesthetized rats (i.v.)
|
Rattus norvegicus
|
95.0
%
|
|
Journal : J. Med. Chem.
Title : Phenylimidazolidin-2-one derivatives as selective 5-HT3 receptor antagonists and refinement of the pharmacophore model for 5-HT3 receptor binding.
Year : 1997
Volume : 40
Issue : 21
First Page : 3369
Last Page : 3380
Authors : Heidempergher F, Pillan A, Pinciroli V, Vaghi F, Arrigoni C, Bolis G, Caccia C, Dho L, McArthur R, Varasi M.
Abstract : A possible bioisosterism between the benzamido and the phenylimidazolidin-2-one moieties has been suggested on the basis of the similarity between the molecular electrostatic potential (MEP) of metoclopramide, a D2 receptor antagonist with weak 5-HT3 receptor antagonist properties, and zetidoline, a D2 receptor antagonist. Starting from this premise, a series of phenylimidazolidin-2-one derivatives bearing a basic azabicycloalkyl or an imidazolylalkyl moiety were synthesized and evaluated for 5-HT3 receptor radioligand binding affinity ([3H]-GR 43,694). In vitro 5-HT3 receptor antagonist activity was tested in the guinea pig ileum assay (GPI). A number of high-affinity ligands were shown to be potent 5-HT3 receptor antagonists in vivo as determined by inhibition of the Bezold--Jarisch reflex in the anesthetized rat. In general, the imidazolylalkyl derivatives were found to be more active than azabicycloalkyls. 1-(3,5-Dichlorophenyl)-3-[(5-methyl-1H-imidazol-4-yl)methyl]imidazoli din-2-one (58), in particular, displayed very high affinity for the 5-HT3 receptor (Ki of 0.038 nM) with a Kb of 5.62 nM in the GPI assay, being more potent than the reference compounds (ondansetron, tropisetron, granisetron, and BRL 46,470) tested. 58 showed an ID50 comparable to that of ondansetron (2.2 micrograms/kg i.v.) in the Bezold--Jarisch reflex. A molecular modeling study based on this structurally novel series of compounds allowed the refinement of previously reported 5-HT3 receptor antagonist pharmacophore models.
|
Percent maximum inhibition against Bezold-Jarisch reflex in 9 rats at a dose of 6 ug/kg, iv
|
Rattus norvegicus
|
88.0
%
|
|
Journal : Bioorg. Med. Chem. Lett.
Title : Indazole and indoline as aromatic bioisosteres in the imidazole class of serotonin 5-HT3 receptor antagonists
Year : 1992
Volume : 2
Issue : 12
First Page : 1509
Last Page : 1512
Authors : Bermudez J, King F, Sanger G
|
Percentage inhibition von benzold jarisch reflex in rats when the compound was administered at dose of 100 ug/Kg 1 hr postadministration
|
Rattus norvegicus
|
80.0
%
|
|
Journal : J. Med. Chem.
Title : Synthesis and biochemical evaluation of tritium-labeled 1-methyl-N-(8-methyl-8-azabicyclo[3.2.1]oct-3-yl)-1H-indazole-3-carboxa mide, a useful radioligand for 5HT3 receptors.
Year : 1990
Volume : 33
Issue : 12
First Page : 3176
Last Page : 3181
Authors : Robertson DW, Bloomquist W, Cohen ML, Reid LR, Schenck K, Wong DT.
Abstract : The advent of potent, highly selective 5HT3 receptor antagonists has stimulated considerable interest in 5HT3 receptor mediated physiology and pharmacology. To permit detailed biochemical studies regarding interaction of the indazole class of serotonin (5HT) antagonists with 5HT3 receptors in multiple tissues, we synthesized 1-methyl-N-(8-methyl-8-azabicyclo[3.2.1]oct-3-yl)-1H-indazole- 3-carboxamide (LY278584, compound 9) in high specific activity, tritium-labeled form. This radioligand was selected as a synthetic target because of its potency as a 5HT3-receptor antagonist, its selectivity for this receptor viz a viz other 5HT-receptor subtypes, and the ability to readily incorporate three tritia via the indazole N-CH3 substituent. Alkylation of N-(8-methyl-8-azabicyclo[3.2.1]oct-3-yl)-1H-indazole-3-carboxamide (8) with sodium hydride and tritium-labeled iodomethane, followed by HPLC purification, resulted in [3H]-9 with a radiochemical purity of 99% and a specific activity of 80.5 Ci/mmol. This radioligand bound with high affinity to a single class of saturable recognition sites in membranes isolated from cerebral cortex of rat brain. The Kd was 0.69 nM and the Bmax was 16.9 fmol/mg of protein. The specific binding was excellent, and accounted for 83-93% of total binding at concentrations of 2 nM or less. The potencies of known 5HT3-receptor antagonists as inhibitors of [3H]-9 binding correlated well with their pharmacological receptor affinities as antagonists of 5HT-induced decreases in heart rate and contraction of guinea pig ileum, suggesting the central recognition site for this radioligand may be extremely similar to or identical with peripheral 5HT3 receptors.
|
Displacement of [3H]granisetron from 5-hydroxytryptamine 3 receptor of rat cortical membrane
|
Rattus norvegicus
|
0.35
nM
|
|
Journal : J. Med. Chem.
Title : Further studies on the interaction of the 5-hydroxytryptamine3 (5-HT3) receptor with arylpiperazine ligands. development of a new 5-HT3 receptor ligand showing potent acetylcholinesterase inhibitory properties.
Year : 2005
Volume : 48
Issue : 10
First Page : 3564
Last Page : 3575
Authors : Cappelli A, Gallelli A, Manini M, Anzini M, Mennuni L, Makovec F, Menziani MC, Alcaro S, Ortuso F, Vomero S.
Abstract : Novel arylpiperazine derivatives bearing lipophilic probes were designed, synthesized, and evaluated for their potential ability to interact with the 5-hydroxytryptamine(3) (5-HT(3)) receptor. Most of the new compounds show subnanomolar 5-HT(3) receptor affinity. Ester 6bc showing a picomolar K(i) value is one of the most potent 5-HT(3) receptor ligands so far synthesized. The structure-affinity relationship study suggests the existence of a certain degree of conformational freedom of the amino acid residues interacting with the substituents in positions 3 and 4 of the quipazine quinoline nucleus. Thus, the tacrine-related heterobivalent ligand 6o was designed in an attempt to capitalize on the evidence of such a steric tolerance. Compound 6o shows a nanomolar potency for both the 5-HT(3) receptor and the human AChE and represents the first example of a rationally designed high-affinity 5-HT(3) receptor ligand showing nanomolar AChE inhibitory activity. Finally, the computational analysis performed on compound 6o allowed the rationalization of the structure-energy determinants for AChE versus BuChE selectivity and revealed the existence of a subsite at the boundary of the 5-HT(3) receptor extracellular domain, which could represent a "peripheral" site similar to that evidenced in the AChE gorge.
|
Displacement of [3H]granisetron from human 5HT3A receptor expressed in HEK293 cells by scintillation counting
|
Homo sapiens
|
1.45
nM
|
|
Journal : J. Med. Chem.
Title : Toward biophysical probes for the 5-HT3 receptor: structure-activity relationship study of granisetron derivatives.
Year : 2010
Volume : 53
Issue : 5
First Page : 2324
Last Page : 2328
Authors : Vernekar SK, Hallaq HY, Clarkson G, Thompson AJ, Silvestri L, Lummis SC, Lochner M.
Abstract : This report describes the synthesis and biological characterization of novel granisetron derivatives that are antagonists of the human serotonin (5-HT(3)A) receptor. Some of these substituted granisetron derivatives showed low nanomolar binding affinity and allowed the identification of positions on the granisetron core that might be used as attachment points for biophysical tags. A BODIPY fluorophore was appended to one such position and specifically bound to 5-HT(3)A receptors in mammalian cells.
|
Binding affinity to 5HT3A receptor
|
None
|
3.981
nM
|
|
Journal : Eur. J. Med. Chem.
Title : Computational analysis of ligand recognition sites of homo- and heteropentameric 5-HT3 receptors.
Year : 2010
Volume : 45
Issue : 11
First Page : 4746
Last Page : 4760
Authors : Moura Barbosa AJ, De Rienzo F, Ramos MJ, Menziani MC.
Abstract : Inhibition of the 5-hydroxytryptamine receptor (5-HT(3)R), a member of the Cys-loop superfamily of Ligand-Gated Ion Channels (LGICs), has been recognized to have important antiemetic effects. With respect to the many other drugs already in use, such as the first generation 5-HT(3)R antagonist granisetron, palonosetron, a second generation antagonist, clearly demonstrates superior inhibition potency towards the 5-HT(3)Rs. Five different receptor monomers, the 5-HT(3)R A-E, have been identified although the A and B subunits are the only known to build functional receptors, the homopentameric 5-HT(3A)R and the heteropentameric 5-HT(3B-A)R (with BBABA subunit arrangement). At present, however, no three-dimensional structure has been reported for any of the 5-HT(3)R subunits. To understand the binding properties of agonists and antagonists, models of the extracellular portion of the 5-HT(3)R A and B subunits are built and assembled into the receptor (homo- and hetero-) pentameric structure on the basis of the known three-dimensional structure of the nicotinic-acetylcholine receptor (nACh-R). The results of docking studies of the natural agonist serotonin and the antagonists palonosetron and granisetron into the modelled homomeric and heteromeric 5-HT(3)R binding interfaces, provide a possible rationalization both of the higher potency of palonosetron with respect to other antagonists, and of its previously reported allosteric binding and positive cooperativity properties.
|
DRUGMATRIX: Serotonin (5-Hydroxytryptamine) 5-HT3 radioligand binding (ligand: [3H] GR-65630)
|
None
|
3.391
nM
|
|
DRUGMATRIX: Serotonin (5-Hydroxytryptamine) 5-HT3 radioligand binding (ligand: [3H] GR-65630)
|
None
|
0.762
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]granisetron from human 5HT3A expressed in HEK293 cells after 1 hr by scintillation counting
|
Homo sapiens
|
1.45
nM
|
|
Journal : Bioorg. Med. Chem. Lett.
Title : High-affinity fluorescent ligands for the 5-HT(3) receptor.
Year : 2012
Volume : 22
Issue : 2
First Page : 1151
Last Page : 1155
Authors : Simonin J, Vernekar SK, Thompson AJ, Hothersall JD, Connolly CN, Lummis SC, Lochner M.
Abstract : The synthesis, photophysical and biological characterization of a small library of fluorescent 5-HT(3) receptor ligands is described. Several of these novel granisetron conjugates have high quantum yields and show high affinity for the human 5-HT(3)AR.
|
Inhibition of human MATE1-mediated ASP+ uptake expressed in HEK293 cells at 20 uM after 1.5 mins by fluorescence assay
|
Homo sapiens
|
67.0
%
|
|
Journal : J. Med. Chem.
Title : Discovery of potent, selective multidrug and toxin extrusion transporter 1 (MATE1, SLC47A1) inhibitors through prescription drug profiling and computational modeling.
Year : 2013
Volume : 56
Issue : 3
First Page : 781
Last Page : 795
Authors : Wittwer MB, Zur AA, Khuri N, Kido Y, Kosaka A, Zhang X, Morrissey KM, Sali A, Huang Y, Giacomini KM.
Abstract : The human multidrug and toxin extrusion (MATE) transporter 1 contributes to the tissue distribution and excretion of many drugs. Inhibition of MATE1 may result in potential drug-drug interactions (DDIs) and alterations in drug exposure and accumulation in various tissues. The primary goals of this project were to identify MATE1 inhibitors with clinical importance or in vitro utility and to elucidate the physicochemical properties that differ between MATE1 and OCT2 inhibitors. Using a fluorescence assay of ASP(+) uptake in cells stably expressing MATE1, over 900 prescription drugs were screened and 84 potential MATE1 inhibitors were found. We identified several MATE1 selective inhibitors including four FDA-approved medications that may be clinically relevant MATE1 inhibitors and could cause a clinical DDI. In parallel, a QSAR model identified distinct molecular properties of MATE1 versus OCT2 inhibitors and was used to screen the DrugBank in silico library for new hits in a larger chemical space.
|
Agonist activity at human 5-HT3B receptor W90C mutant by FLIPR assay
|
Homo sapiens
|
130.0
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor.
Year : 2013
Volume : 21
Issue : 23
First Page : 7523
Last Page : 7528
Authors : Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC.
Abstract : Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
|
Agonist activity at human 5-HT3B receptor H73A mutant by FLIPR assay
|
Homo sapiens
|
640.0
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor.
Year : 2013
Volume : 21
Issue : 23
First Page : 7523
Last Page : 7528
Authors : Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC.
Abstract : Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
|
Agonist activity at human wild type 5-HT3A/5-HT3B receptor expressed in HEK293 cells by FLIPR assay
|
Homo sapiens
|
500.0
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor.
Year : 2013
Volume : 21
Issue : 23
First Page : 7523
Last Page : 7528
Authors : Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC.
Abstract : Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
|
Agonist activity at human 5-HT3A receptor D165K mutant by FLIPR assay
|
Homo sapiens
|
190.0
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor.
Year : 2013
Volume : 21
Issue : 23
First Page : 7523
Last Page : 7528
Authors : Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC.
Abstract : Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
|
Agonist activity at human 5-HT3A receptor D165A mutant by FLIPR assay
|
Homo sapiens
|
190.0
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor.
Year : 2013
Volume : 21
Issue : 23
First Page : 7523
Last Page : 7528
Authors : Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC.
Abstract : Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
|
Agonist activity at human 5-HT3A receptor S163T mutant by FLIPR assay
|
Homo sapiens
|
94.0
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor.
Year : 2013
Volume : 21
Issue : 23
First Page : 7523
Last Page : 7528
Authors : Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC.
Abstract : Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
|
Agonist activity at human 5-HT3A receptor S163A mutant by FLIPR assay
|
Homo sapiens
|
160.0
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor.
Year : 2013
Volume : 21
Issue : 23
First Page : 7523
Last Page : 7528
Authors : Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC.
Abstract : Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
|
Agonist activity at human 5-HT3A receptor F130A mutant by FLIPR assay
|
Homo sapiens
|
130.0
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor.
Year : 2013
Volume : 21
Issue : 23
First Page : 7523
Last Page : 7528
Authors : Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC.
Abstract : Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
|
Agonist activity at human 5-HT3A receptor Y73S mutant by FLIPR assay
|
Homo sapiens
|
74.0
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor.
Year : 2013
Volume : 21
Issue : 23
First Page : 7523
Last Page : 7528
Authors : Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC.
Abstract : Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
|
Agonist activity at human 5-HT3A receptor Y73F mutant by FLIPR assay
|
Homo sapiens
|
450.0
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor.
Year : 2013
Volume : 21
Issue : 23
First Page : 7523
Last Page : 7528
Authors : Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC.
Abstract : Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
|
Agonist activity at human wild type 5-HT3A receptor expressed in HEK293 cells by FLIPR assay
|
Homo sapiens
|
320.0
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor.
Year : 2013
Volume : 21
Issue : 23
First Page : 7523
Last Page : 7528
Authors : Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC.
Abstract : Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
|
Agonist activity at human 5-HT3A receptor Y73A mutant by FLIPR assay
|
Homo sapiens
|
88.0
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor.
Year : 2013
Volume : 21
Issue : 23
First Page : 7523
Last Page : 7528
Authors : Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC.
Abstract : Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
|
Binding affinity to human 5-HT3B receptor E170A mutant after 24 hrs by liquid scintillation counting analysis
|
Homo sapiens
|
0.11
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor.
Year : 2013
Volume : 21
Issue : 23
First Page : 7523
Last Page : 7528
Authors : Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC.
Abstract : Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
|
Binding affinity to human 5-HT3B receptor Y143A mutant after 24 hrs by liquid scintillation counting analysis
|
Homo sapiens
|
0.2
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor.
Year : 2013
Volume : 21
Issue : 23
First Page : 7523
Last Page : 7528
Authors : Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC.
Abstract : Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
|
Binding affinity to human 5-HT3B receptor F130A mutant after 24 hrs by liquid scintillation counting analysis
|
Homo sapiens
|
0.78
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor.
Year : 2013
Volume : 21
Issue : 23
First Page : 7523
Last Page : 7528
Authors : Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC.
Abstract : Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
|
Binding affinity to human 5-HT3B receptor W90C mutant after 24 hrs by liquid scintillation counting analysis
|
Homo sapiens
|
0.25
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor.
Year : 2013
Volume : 21
Issue : 23
First Page : 7523
Last Page : 7528
Authors : Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC.
Abstract : Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
|
Binding affinity to human 5-HT3B receptor H73A mutant after 24 hrs by liquid scintillation counting analysis
|
Homo sapiens
|
0.22
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor.
Year : 2013
Volume : 21
Issue : 23
First Page : 7523
Last Page : 7528
Authors : Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC.
Abstract : Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
|
Binding affinity to human wild type 5-HT3A/5-HT3B receptor expressed in HEK293 cells after 24 hrs by liquid scintillation counting analysis
|
Homo sapiens
|
0.2
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor.
Year : 2013
Volume : 21
Issue : 23
First Page : 7523
Last Page : 7528
Authors : Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC.
Abstract : Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
|
Binding affinity to human 5-HT3A receptor D165K mutant after 24 hrs by liquid scintillation counting analysis
|
Homo sapiens
|
0.44
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor.
Year : 2013
Volume : 21
Issue : 23
First Page : 7523
Last Page : 7528
Authors : Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC.
Abstract : Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
|
Binding affinity to human 5-HT3A receptor D165A mutant after 24 hrs by liquid scintillation counting analysis
|
Homo sapiens
|
0.37
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor.
Year : 2013
Volume : 21
Issue : 23
First Page : 7523
Last Page : 7528
Authors : Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC.
Abstract : Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
|
Binding affinity to human 5-HT3A receptor S163T mutant after 24 hrs by liquid scintillation counting analysis
|
Homo sapiens
|
0.19
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor.
Year : 2013
Volume : 21
Issue : 23
First Page : 7523
Last Page : 7528
Authors : Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC.
Abstract : Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
|
Binding affinity to human 5-HT3A receptor S163A mutant after 24 hrs by liquid scintillation counting analysis
|
Homo sapiens
|
0.36
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor.
Year : 2013
Volume : 21
Issue : 23
First Page : 7523
Last Page : 7528
Authors : Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC.
Abstract : Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
|
Binding affinity to human 5-HT3A receptor F130Y mutant after 24 hrs by liquid scintillation counting analysis
|
Homo sapiens
|
0.49
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor.
Year : 2013
Volume : 21
Issue : 23
First Page : 7523
Last Page : 7528
Authors : Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC.
Abstract : Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
|
Binding affinity to human 5-HT3A receptor F130A mutant after 24 hrs by liquid scintillation counting analysis
|
Homo sapiens
|
0.78
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor.
Year : 2013
Volume : 21
Issue : 23
First Page : 7523
Last Page : 7528
Authors : Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC.
Abstract : Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
|
Binding affinity to human 5-HT3A receptor Y73S mutant after 24 hrs by liquid scintillation counting analysis
|
Homo sapiens
|
0.41
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor.
Year : 2013
Volume : 21
Issue : 23
First Page : 7523
Last Page : 7528
Authors : Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC.
Abstract : Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
|
Binding affinity to human 5-HT3A receptor Y73F mutant after 24 hrs by liquid scintillation counting analysis
|
Homo sapiens
|
0.9
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor.
Year : 2013
Volume : 21
Issue : 23
First Page : 7523
Last Page : 7528
Authors : Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC.
Abstract : Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
|
Binding affinity to human 5-HT3A receptor Y73A mutant after 24 hrs by liquid scintillation counting analysis
|
Homo sapiens
|
0.6
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor.
Year : 2013
Volume : 21
Issue : 23
First Page : 7523
Last Page : 7528
Authors : Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC.
Abstract : Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
|
Binding affinity to human 5-HT3B receptor I183A mutant after 24 hrs by liquid scintillation counting analysis
|
Homo sapiens
|
0.16
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor.
Year : 2013
Volume : 21
Issue : 23
First Page : 7523
Last Page : 7528
Authors : Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC.
Abstract : Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
|
Binding affinity to human wild type 5-HT3A receptor expressed in HEK293 cells after 24 hrs by liquid scintillation counting analysis
|
Homo sapiens
|
0.53
nM
|
|
Journal : Bioorg. Med. Chem.
Title : Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor.
Year : 2013
Volume : 21
Issue : 23
First Page : 7523
Last Page : 7528
Authors : Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC.
Abstract : Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
