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)

A series of N-(azabicyclo-3-yl)-2,3-dihydrobenzofuran-7-carboxamide derivatives were synthesized and evaluated for serotonin-3 (5-HT3) receptor antagonistic activities assessed by 5-HT3 receptor binding (in vitro) and by the ability to antagonize the von Bezold-Jarisch reflex in rats (in vivo). In these compounds, 1-azabicyclo[2.2.2]oct-3-yl derivatives were more potent than 8-methyl-8-azabicyclo[3.2.1]oct-3-yl derivatives for 5-HT3 receptor antagonistic activities. The introduction of methyl groups at position 2 of the dihydrobenzofuran ring increased the pharmacological activities (dimethyl > monomethyl > dihydro). Furthermore, the stereoisomers of dimethyl-, monomethyl-, and dihydrobenzofuran derivatives were prepared to evaluate the stereoselectivity of their 5-HT3 receptor binding affinities. Concerning the basic part, the compounds bearing (S)-1-azabicyclo[2.2.2]octan-3-yl moiety were more potent than their counterparts. With respect to the methyl substituent at position 2 of the dihydrobenzofuran ring, the rank order of the potency was dimethyl > or = (2S)-methyl > (2R)-methyl > dihydro. These results suggest that the (2S)-methyl group of the dihydrobenzofuran part contributes to the enhancement of the pharmacological activity. Among these compounds, (S)-N-(1-azabicyclo[2.2.2]oct-3-yl)-5-chloro-2,3-dihydro-2,2- dimethylbenzofuran-7-carboxamide hydrochloride (24) showed the highest affinity for 5-HT3 receptors (Ki = 0.055 nM), and the most potent antagonistic activity on the von Bezold-Jarisch reflex (ED50 = 0.18 microgram/kg i.v.).
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PMID:Synthesis and structure-activity relationships of 2,3-dihydrobenzofuran-7-carboxamide derivatives as potent serotonin-3 (5-HT3) receptor antagonists. 812 72

The potency of Ondansetron (Zofran, Glaxo), a highly specific 5HT3 antagonist in preventing the very unfavorable complication during introducing anesthesia, i.e. a Bezold-Jarisch reflex-like reaction, was studied in a clinical trial. A total of 20 patients (12 males and 8 females aged 19-65 years) admitted for clinical surgical treatment participated in the trial. Zofran (8 mg in 500 ml Ringer solution) was injected intravenously one hour before intubation at a flow rate of 8 ml. min-1. Systolic and diastolic blood pressure, central venous pressure, breathing frequency and minute ventilation, pCO2 and pO2 in venous blood, electrocardiogram monitoring (ECG) and several common features such as spontaneous muscle activity, palpebral reflexes, skin and mucose surfaces were continuously observed. Visual, auscultatory and X-ray control of the lungs was effected. It was found that blockade of 5HT3 receptors prevented the appearance of Bezold-Jarisch reflex-like reaction. The drug could successfully be used in anesthesiological practice.
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PMID:Evaluation of ondansetron as a drug for premedication. 820 75

1. The pharmacological properties of RS 23597-190 (3-(piperdine-1-yl)-propyl-4-amino-5-chloro-2-methoxy benzoate hydrochloride) have been studied in vitro and in vivo. 2. RS 23597-190 competitively antagonized 5-HT4 receptor-mediated relaxations of rat, carbachol precontracted oesophageal muscularis mucosae, (pA2 = 7.8 +/- 0.1; Schild slope = 1.2 +/- 0.2). Affinity estimates (-log KB) at 5-HT4 receptors using either renzapride or SC-53116 as agonists yielded a -log KB value of 8.0 +/- 0.01. In contrast, RS 23597-190 failed to antagonize contractile responses to 5-HT of guinea-pig ileal 5-HT3 receptors, even at concentrations up to 10 microM. 3. Increases in short-circuit current, induced by 5-HT, were studied in guinea-pig ileal mucosal sheets. Concentration-response curves to 5-HT were biphasic, with the high potency phase to 5-HT inhibited by RS 23597-190 and mimicked by 5-methoxytryptamine. The -log KB value for RS 23597-190 at the high potency phase was 7.3 confirming that 5-HT4 receptors mediated the high potency phase. 4. In rat isolated vagus nerve, 5-HT elicited a slow, maintained depolarization at low concentrations and a rapid, transient depolarization at higher concentrations. The high potency, slow depolarizing phase to 5-HT was abolished selectively in the presence of 1 microM RS 23597-190 and the low potency phase was abolished selectively in the presence of 1 microM ondansetron. These data confirm that 5-HT4 and 5-HT3 receptors mediated slow and fast depolarization responses, respectively. 5. At 5-HT3 binding sites in membranes from NG 108-15 cells, labelled by [3H]-quipazine, RS 23597-190 exhibited an apparent affinity (- log Ki) of 5.7 +/- 0.1. At 5-HT3 receptors in membranes from rat cerebral cortex, labelled by [3H]-RS 42358-197, the apparent affinity (- log Ki) of RS 23597-190 was also 5.7 +/- 0.1. In both studies, Hill coefficients were not significantly different from unity. At 5-HT1A, 5-HT2,muscarinic M1, M2, M3, M4 and dopamine D1 and D2 receptors, RS 23597-190 exhibited low apparent affinities, with all - log Ki values less than 5.5.6. Intravenous infusion of RS 23597-190 in the conscious, restrained rat antagonized the von Bezold Jarisch reflex induced by 2-methyl 5-HT, with an ID50 of 300 microg kg-1 min-1, i.v. In the anaesthetized,bilaterally vagotomized micropig, RS 23597-190 (6 mg kg-1, i.v.) antagonized 5-HT-induced tachycardia with a half-life of 77 (63-99) min. Transient arrhythmic effects were noted after administration of the compound.7. In conclusion, RS 23597-190 acts as a high affinity, selective competitive antagonist at 5-HT4 receptors. Thus, the compound appears to be a useful tool for 5-HT4 receptor identification in vitro. In vivo, the compound is rapidly metabolized in pigs such that 5-HT4 blockade is not maintained. However,in the rat, when given by infusion, RS 23597-190 antagonizes 5-HT3 mediated responses, at doses consistent with a low affinity 5-HT3 receptor. These data suggest that, under appropriate experimental conditions, RS 23597-190 may also be used in vivo to characterize further 5-HT4 receptor function.
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PMID:RS 23597-190: a potent and selective 5-HT4 receptor antagonist. 822 Aug 71

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).
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PMID:5-HT3 receptor antagonists. 3. Quinoline derivatives which may be effective in the therapy of irritable bowel syndrome. 823 Jan 19

The pharmacological activity of RS 42358-197, a novel 5-HT3 receptor antagonist has been evaluated in vitro and in vivo. In functional experiments in vitro, RS 42358-197 behaved as a competitive antagonist against 5-HT-induced contractions in the guinea pig ileum (low-potency phase), yielding a pA2 estimate of 8.1. RS 42358-197 was devoid of any agonistic or antagonistic activity at 5-HT1-like receptors (contraction of canine saphenous vein), 5-HT2 receptors (contraction of rabbit aorta) or 5-HT4 receptors (contraction of guinea pig ileum, high-potency phase). RS 42358-197 failed to affect the concentration-effect curve to substance P in guinea pig ileum. In anesthetized rats. RS 42358-197, administered by the intravenous, intraduodenal or transdermal route, dose-dependently inhibited the Bezold-Jarisch reflex induced by 2-methyl 5-HT (ID50:0.05 micrograms/kg; i.v., 5.7 micrograms/kg; i.d., and 11.6 micrograms/chamber, respectively). In this regard, when administered intraduodenally, RS 42358-197 was more potent and exhibited a longer duration of action than either ondansetron or granisetron. In dogs, RS 42358-197, administered either intravenously or orally, dose-dependently inhibited the emesis induced by cisplatin, actinomycin and cyclophosphamide, but not that induced by apomorphine. When tested at maximally effective doses against cisplatin-induced emesis in dogs, RS 42358-197 had a longer duration of antiemetic activity (> 6 h) than ondansetron (2 h). RS 42358-197, administered orally, also afforded protection against cisplatin-induced emesis in ferrets. At doses that showed marked anti-emetic activity in dogs (10-100 micrograms/kg; i.v. and 100-1000 micrograms/kg; i.d.), RS 42358-197 did not produce any hemodynamic changes.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:RS 42358-197, a novel and potent 5-HT3 receptor antagonist, in vitro and in vivo. 835 89

A series of piperazinylquinoxalines has been synthesized and studied as 5-HT3 receptor antagonists in different preparations. Antagonism to 5-HT in the longitudinal muscle of the guinea pig ileum was particularly prominent in cyanoquinoxaline derivatives with an alkyl substitutuent on the piperazine moiety. The pA2 of some selected compounds against the 5-HT3 agonist 2-methyl-5HT in the guinea pig ileum was in the range of tropisetron or ondansetron, and one of them, 7e, was more potent than these reference compounds by approximately 2 or 3 orders of magnitude. However, these compounds were markedly less potent than either tropisetron or ondansetron as displacers of 3H-BRL 43694 binding to rat cortical membranes or as antagonists of the Bezold-Jarisch reflex in rats. Piperazinylcyanoquinoxalines represent a new class of 5-HT3 antagonists with a selective effect on guinea pig peripheral receptors.
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PMID:Novel antagonists of 5-HT3 receptors. Synthesis and biological evaluation of piperazinylquinoxaline derivatives. 841 Sep 88

(+)-8,9-Dihydro-10-dihydro-10-methyl-7-[(5-methyl-4-imidazolyl) methyl]pyrido-[1,2-a]indol-6(7H)-one hydrochloride (FK1052) is a newly designed and synthesized 5-hydroxytryptamine (5-HT)3 receptor antagonist with 5-HT4 receptor antagonistic activity. This compound, as well as ondansetron and granisetron, dose-dependently inhibited the von Bezold-Jarish reflex, a 5-HT3 receptor-mediated response, after intravenous (i.v.) and intraduodenal (i.d.) dosing to rats. The ID50 values showed FK1052 (0.28 microgram/kg, i.v., 5.23 micrograms/kg, i.d.) to be more potent than ondansetron (5.23 micrograms/kg, i.v., 170 micrograms/kg, i.d.) and granisetron (0.70 micrograms/kg, i.v., 66 micrograms/kg, i.d.). Furthermore, bioavailabilities of the test drugs by ID50 ratio (i.d./i.v.) showed that FK1052(17) was better absorbed than ondansetron(33) and granisetron(94) and possessed a similar duration of action to that of ondansetron and granisetron. We also examined the effects on 2-methyl-5-HT-, 5-HT- and 5-methoxytryptamine-induced contractions of guinea pig isolated ileum. FK1052, ondansetron and granisetron concentration-dependently inhibited 2-methyl-5-HT, a 5-HT3 agonist-induced contraction. The pA2 values for the 5-HT3 receptor indicated that FK1052 (8.36) was 40 times and three times more potent than ondansetron (6.79) and granisetron (7.86), respectively. FK1052, unlike ondansetron and granisetron, inhibited the 5-HT4-mediated component of concentration-response curve to 5-HT. Furthermore, FK1052 suppressed 5-methoxytryptamine, a 5-HT4 agonist-induced contraction in a concentration-dependent but insurmountable manner.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Pharmacological characterization of FK1052, a dihydropyridoindole derivative, as a new serotonin 3 and 4 dual receptor antagonist. 849 21

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.
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PMID:5-HT3 receptor antagonists. 2. 4-Hydroxy-3-quinolinecarboxylic acid derivatives. 849 41

1. The 5-HT3 receptor antagonist, zacopride, and its enantiomers, R(+)-zacopride and S(-)-zacopride, were examined in three pharmacological models: (i) 5-HT-induced depolarization of the mouse isolated vagus nerve preparation, (ii) the 5-HT-evoked von Bezold-Jarisch reflex in the mouse, and (iii) the mouse light:dark box model of anxiety. Other standard 5-HT3 receptor antagonists were also included for comparison in these studies. 2. Racemic zacopride, and both of the enantiomers, displayed potent 5-HT3 receptor antagonist activity in the isolated vagus nerve and in the von Bezold-Jarisch model. No 5-HT3 receptor agonist or partial agonist effects of these compounds were detected. 3. In the isolated vagus nerve, R(+)-zacopride and ondansetron were surmountable 5-HT3 receptor antagonists (pA2 values of 9.3 and 8.3, respectively), whereas racemic zacopride, S(-)-zacopride and tropisetron were insurmountable antagonists, markedly suppressing the maximum response to 5-HT. 4. In vivo, racemic zacopride, R(+)-zacopride, S(-)-zacopride and WAY100289 were potent antagonists of the 5-HT-evoked von Bezold-Jarisch reflex, with minimum effective doses (lowest dose required to reduce the reflex by > or = 85%; MED85) of 1.0, 3.0, 0.3 and 3.0 micrograms kg-1, s.c., respectively. 5. Racemic zacopride, R(+)-zacopride and S(-)-zacopride were active in the mouse light:dark box model of anxiety, with similar potencies (minimum effective dose 1 microgram kg-1, s.c.) and similar active dose-ranges (1-1000 micrograms kg-1, s.c.). 6. The doses of racemic zacopride, R( + )-zacopride and S(-)-zacopride required to block 5-HT3receptors in vivo correlated reasonably well with their potencies in an anxiety model within the same species. In these studies, there was no evidence of a marked difference between the anxiolytic potencies ofR( + )-zacopride and S(-)-zacopride.
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PMID:The enantiomers of zacopride: an intra-species comparison of their potencies in functional and anxiolytic models. 854 76

1. In the present study we evaluated the receptor selectivity of the potent histamine H3 receptor antagonist, iodophenpropit (IPP) in comparison with the prototype antagonist, thioperamide. 2. IPP proved to be a potent competitive H3 receptor antagonist as measured against (R)-alpha-methylhistamine-induced inhibition of electrically-evoked contractions of the guinea-pig jejunum (pA2 = 9.12 +/- 0.06, Schild slope: 1.0 +/- 0.1, n = 8). In the same assay, thioperamide was slightly less potent (pA2 = 8.9 +/- 0.2). 3. In radioligand binding studies, IPP showed a high affinity for the H3 receptor. Displacement of [125I]-IPP binding to rat cortex membranes by unlabelled IPP resulted in a Ki value of 0.97 +/- 0.06 nM (n = 3). In contrast, IPP showed only a weak affinity for the histamine H1- and H2 receptor. Displacement of [3H]-mepyramine and [125I]-iodoaminopotentidine binding to respectively guinea-pig H1- and human H2 receptors by IPP resulted in Ki values of 1.71 +/- 0.32 microM (n = 3) and 2.28 +/- 0.81 microM (n = 3). For thioperamide the affinities for the H1-, H2- and H3 receptor were respectively > 10 microM, > 10 microM and 4.3 +/- 1.6 nM (n = 7). 4. Testing IPP and thioperamide in 39 different receptor binding assays revealed that IPP showed relatively high affinity for the 5-hydroxytryptamine 5-HT3 receptor (Ki = 11 +/- 1 nM, n = 3), the alpha 2-adrenoceptor (Ki = 120 +/- 5 nM, n = 3) and the sigma receptor (Ki = 170 +/- 70 nM, n = 3). Thioperamide showed relatively high affinity for the 5-HT3 receptor (Ki = 120 +/- 30 nM, n = 3) and the sigma receptor (Ki = 180 +/- 90 nM, n = 3). 5. Due to the low density of histamine H3 receptors in the brain, the interaction of IPP with the 5-HT3-, the alpha 2- and the sigma receptor might interfere with [125I]-IPP binding to rat cortex membranes. Yet, in this preparation [125I]-IPP binding was not influenced by ondansetron, yohimbine or haloperidol. The interaction with the 5-HT3 receptor was not restricted to IPP or thioperamide, but was alsofound with other H3 receptor antagonists. The potent H3 receptor agonist imetit, a compound belongingto the same chemical class of IPP, also interacted with the 5-HT3 receptor (Ki = 240 +/- 40 nM). In contrast,histamine or the H3 receptor agonist, (R)-a-methylhistamine showed no affinity for the 5-HT3 receptor.7 In the guinea-pig isolated ileum, imetit evoked concentration-dependent contractions, resulting in apD2 value of 4.72 +/- 0.03 (n = 9). The contractions were antagonized by ondansetron, yielding a pA2 valueof 7.1 +/- 0.1 (n = 9). Similarly ondansetron antagonized the contractions evoked by the 5-HT3 receptoragonist, 2-methyl-5-HT with a pA2 value of 7.3 +/- 0.1 (n = 4). IPP and thioperamide did not mimic 2-methyl-5-HT but non-competitively inhibited the 2-methyl-5-HT-induced contractions of thispreparation.8 In an in vivo model for 5-HT3 activity, the Von Bezold Jarisch reflex, thioperamide showedantagonism in low dosages, which correlated well with the affinity for the 5-HT3 receptor site. Yet, athigher dosages no further 5-HT3 receptor antagonism was observed. For IPP no 5-HT3 receptor activitycould be observed in vivo.9 In the present study we showed that many H3 receptor compounds, that are regarded as highlyselective (including the prototype drug, thioperamide), also interact with the 5-HT3 receptor, albeit athigher drug concentrations.Keywords.: Histamine H3-receptor; iodophenpropit; thioperamide; receptor selectivity; 5-hydroxytryptamine 5-HT3 receptor;guinea-pig intestine; rat brain; Von Bezold Jarisch reflex
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PMID:Evaluation of the receptor selectivity of the H3 receptor antagonists, iodophenpropit and thioperamide: an interaction with the 5-HT3 receptor revealed. 856 66


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