Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P46098 (5-HT3 receptor)
 2,290 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ligands of various chemical classes (e.g., indoles, indazoles, benzamides, carbazoles, and quinolines) have demonstrated high affinity for the 5-HT3 receptor in radiolabeled ligand-binding studies, and have shown 5-HT3 receptor antagonistic activity in functional assays which utilize the excitatory effects of 5-HT on enteric neurons and autonomic afferents. Several 5-HT3 antagonists are currently being evaluated for potential use in the treatment of migraine, schizophrenia, and anxiety, and a few have already demonstrated high efficacy as antiemetics in cancer chemotherapy. The purpose of this presentation is to highlight the significant structure-affinity relationships (SAFIR) and common geometrical features among 5-HT3 receptor ligands, and to describe the three-dimensional pharmacophore for the 5-HT3 recognition site derived from computational techniques. The chemical template containing the recognition elements (functional groups) for the 5-HT3 receptor are: an aromatic or heteroaromatic ring system, a coplanar carbonyl group, and a nitrogen center, interrelated by well-defined distances. Two "binding shapes" or "active shapes" for 5-HT3 ligands have been identified from detailed conformational analyses.
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PMID:Molecular modeling of 5-HT3 receptor ligands. 181 57

A novel structural class of highly potent and selective 5-HT3 receptor antagonists is described. The compounds in this new series contain a thiazole moiety linking an aromatic group and a nitrogen-containing basic region; the thiazole group appears to be acting as a carbonyl bioisostere in this system. An optimized member of this series, 4-(2-methoxyphenyl)-2-[[4(5)-methyl-5(4)-imidazolyl]methyl]thiazole (5), exhibits oral activity in the Bezold-Jarisch reflex paradigm comparable to or better than the standard agents ondansetron (1) and ICS-205-930 (2). Several of the structure-activity relationships are rationalized in terms of a computer pharmacophore model for 5-HT3 receptor binding.
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PMID:Thiazole as a carbonyl bioisostere. A novel class of highly potent and selective 5-HT3 receptor antagonists. 221 24

A quantitative molecular model was derived to predict drug affinities for 5-hydroxytryptamine3 (5-HT3) receptors. The model was based on the molecular characteristics of a "learning set" of 40 pharmacological agents that had been analyzed previously in radioligand binding studies. Molecules were analyzed for various structural features, i.e., the presence of a benzenoid ring and nitrogen atom, substitutions on the benzenoid ring, the location of the substitutions on the nitrogen, and the molecular characteristics of the most direct pathway from the benzenoid ring to the nitrogen. Weighting factors, based on published 5-HT3 receptor affinity data, were then assigned to each of 10 molecular characteristics. The derived computational model predicts accurately the affinities of the learning set for the 5-HT3 receptor (r = 0.98; p less than 0.001). The computational model was then used to predict the receptor affinities of a "test set" of 40 pharmacological agents. The predicted values for these agents also correlate significantly (r = 0.83; p less than 0.001) with drug affinities for the 5-HT3 receptor, as determined by radioligand binding assays. This first line screening approach allows for the accurate prediction of drug affinities based on molecular characteristics with minimal dependence upon animal tissues or radioactivity.
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PMID:Quantitative molecular analysis predicts 5-hydroxytryptamine3 receptor binding affinity. 223 92

The synthesis and structure-activity relationships of a series of new azabicycloalkanes as 5-HT3 (serotonin-3) receptor antagonists are described. Our study on the azabicycloalkaneacetamide derivatives showed that 2,3-dihydroindole as the aromatic ring moiety afforded potent 5-HT3 receptor antagonist activity, as judged by blockade of bradycardia induced by i.v. injection of 2-methylserotonin in anesthetized rats. 7-Azaindole as the aromatic moiety afforded weak 5-HT3 receptor antagonists activity. The best 5-HT3 antagonists in this study were endo-3,3-diethyl- (9k) and 3,3-dimethyl-2,3-dihydro-1-[(8-methyl-8-azabicyclo[3.2.1]oct-3-yl) acetyl-1H-indole (9d), being approximately 10-fold more potent than ondansetron (1). This study shows that the azabicycloalkaneacetyl group is a new pharmacophoric element as a basic nitrogen and a linking carbonyl moiety.
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PMID:New 5-HT3 (serotonin-3) receptor antagonists. IV. Synthesis and structure-activity relationships of azabicycloalkaneacetamide derivatives. 755 80

Synthesis and pharmacological evaluation of a series of condensed quinoline derivatives bearing a basic nitrogen on piperazine or [(dimethylamino)ethyl]thio moieties attached at the 2-position of the quinoline nucleus are described. 5-HT receptor binding studies revealed, for most of the compounds studied, nanomolar affinity for the 5-HT3 receptor subtype. The most active compound, benzopyrano[3,4-c]quinoline derivative 5f, displayed a Ki value very similar to that reported for quipazine along with an improved selectivity. Functional and in vivo testing carried out on three selected compounds showed that 5f,j,n are potent 5-HT3 receptor antagonists with potencies in the same range as the best known 5-HT3 receptor antagonists ondansetron, tropisetron, and zacopride. The crystal and molecular structures of compounds 5f,j,n were determined by single-crystal X-ray diffraction and used as starting structures for molecular modeling studies. Comparative molecular field analysis (CoMFA) was applied to binding constants of compounds 5a-p and 6a-h. The cross-validated r2, derived from partial least-squares calculations, indicated a good predictive capacity for affinity values in the series of compounds investigated. Evidence for the prediction capacity is provided in the form of plots of actual vs predicted pKi values. The steric and electrostatic features of the CoMFA-derived model are presented as standard coefficient contour maps of steric and electrostatic fields.
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PMID:Novel, potent, and selective 5-HT3 receptor antagonists based on the arylpiperazine skeleton: synthesis, structure, biological activity, and comparative molecular field analysis studies. 762 8

We assessed the 5-HT3-receptor antagonist effects of 4,5,6,7-1H-benzimidazole compounds which are derivatives of YM060, a potent and selective 5-HT3-receptor antagonist, in isolated guinea pig colon. YM114 (KAE-393), YM-26103-2, YM-26308-2 (3 x 10(-9) to 3 x 10(-8) M) produced concentration-dependent shifts to the right of the dose-response curves for both 5-HT and 2-methyl-5-HT (2-Me-5-HT). YM114 (pA2 = 9.08 against 5-HT, pA2 = 8.88 against 2-Me-5-HT), YM-26103-2 (pA2 = 8.27 against 5-HT, pA2 = 8.19 against 2-Me-5-HT), and YM-26308-2 (pA2 = 8.58 against 5-HT, pA2 = 8.4 against 2-Me-5-HT) showed similar pA2 values irrespective of the agonist used, suggesting that they have 5-HT3-receptor blocking activity irrespective of the N-position at the aromatic ring. Since these compounds have an asymmetric center, their enantiomers exist. The S-isomers were one to three orders of magnitude less potent than the respective R-isomer compounds, indicating that the stereochemical configuration of 4,5,6,7-tetrahydro-1H-benzimidazoles is an important determinant of their affinity for 5-HT3 receptors. These results suggest that the highly potent 5-HT3 receptor antagonism and high selectivity for 5-HT3 receptors of 4,5,6,7-tetrahydro-1H-benzimidazole derivatives are conserved irrespective of the position of the nitrogen atom in the aromatic ring and that 5-HT3 receptors favor the R-isometric conformation of these compounds.
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PMID:Studies on serotonin (5-HT)3-receptor antagonist effects of enantiomers of 4,5,6,7-tetrahydro-1H-benzimidazole derivatives. 763 36

A series of pyrido[1,2-alpha]indol-6(7-H)-ones was prepared and evaluated for 5-HT3 receptor antagonist activity. The structural requirements for the 5-HT3 receptor antagonist have been defined as an aromatic moiety, a basic nitrogen, and a linking acyl group. The (5-methylimidazol-4-yl)methyl group as a basic nitrogen moiety was an important element for high potency. The highest potency was observed for compounds which have 7- and 10-methyl substituents on the pyrido[1,2-alpha]indol-6(7H)-one ring. From this series, (+)-11b (FK 1052) was selected for further evaluation. FK 1052 was a potent 5-HT3 receptor antagonist in the Bezold-Jarisch reflex test in rats (ED50 0.9 microgram/kg, i.v.) and a very effective antiemetic agent against cisplatin-induced emesis in dogs (ED50 1.2 x 2 micrograms/kg, i.v. and 2.7 x 2 micrograms/kg, p.o.).
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PMID:New 5-HT3 (serotonin-3) receptor antagonists. I. Synthesis and structure-activity relationships of pyrido[1,2-a]indoles. 769 71

The emetic effects of five anticancer drugs, cyclophosphamide, nitrogen mustard-N-oxide, actinomycin D, 5-fluorouracil and L-asparaginase, and the effects of bilateral abdominal vagotomy and bilateral greater splanchnic nerve section or a 5-HT3 receptor antagonist on the emesis induced by these drugs were investigated in dogs. Cyclophosphamide (20 mg/kg, i.v.), nitrogen mustard-N-oxide (5 mg/kg, i.v.) and actinomycin D (50 micrograms/kg, i.v.) caused vomiting in dogs with a long latency period. 5-Fluorouracil (5 mg/kg, i.v.) and L-asparaginase (2000 K.U./kg, i.v.) failed to induce vomiting. Bilateral abdominal vagotomy and bilateral greater splanchnic nerve section completely inhibited the vomiting induced by the former three anticancer drugs. Furthermore, the vomiting was inhibited completely by intravenous administration of ICS205930 (2 x 0.1 mg/kg), a 5-HT3 receptor antagonist. These results suggest that activation of visceral afferents through 5-HT3 receptors mediates the vomiting induced by cyclophosphamide, nitrogen mustard-N-oxide and actinomycin D.
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PMID:Emetic effects of anticancer drugs and involvement of visceral afferent fibers and 5-HT3 receptors in dogs. 811 85

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.
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PMID:Development of high-affinity 5-HT3 receptor antagonists. Structure-affinity relationships of novel 1,7-annelated indole derivatives. 824 39

The syntheses of benzamides containing azabicyclo[x.y.z] side chains and their 5-HT4 receptor agonist and 5-HT3 receptor antagonist properties are described. These compounds were designed to mimic higher energy conformations of quinolizidine and indolizidine. High potency was achieved for both activities although an exactly paralleling SAR was not apparent. Introduction of O and S resulted in only marginal differences in potency which was more apparent for 5-HT3 antagonism. The introduction of a methyl group alpha to the basic nitrogen resulted in a reduction in 5-HT4 receptor agonist potency. Renzapride (5f) was identified for further evaluation for which both enantiomers had an identical pharmacological profile, as did an azatricyclic 9b, which contained a combination of the steric bulk of the two separate enantiomers.
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PMID:Substituted benzamides with conformationally restricted side chains. 5. Azabicyclo[x.y.z] derivatives as 5-HT4 receptor agonists and gastric motility stimulants. 845 97


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