Abstract
The involvement of the recently characterized 5-HT4 receptor in the actions of 5-hydroxytryptamine (5-HT) on jejunal, ileal and colonic electrogenic ion secretion was investigated in the rat in-vivo. 5-HT and the 5-HT1-, 5-HT2- and 5-HT4-receptor agonist 5-methoxytryptamine (5-MeOT), induced a rise in transintestinal PD in all regions of the gut. However, the 5-HT4-receptor agonists renzapride and cisapride had no effect. Furthermore, the 5-HT4-receptor antagonists SDZ 205-557 (2-diethylaminoethyl-[2-methoxy-4-amino-5-chloro] benzoate), tropisetron and SB 204070 ([1-butyl-4-piperidinylmethyl]-8-amino-7-chloro-1,4- benzodioxan-5-carboxylate hydrochloride) did not affect the secretory response to either 5-HT or 5-MeOT in the jejunum, but did cause a small inhibition in the ileum and colon. It is concluded that 5-HT4 receptors do not make a contribution to the electrically monitored 5-HT intestinal secretory response in the rat jejunum in-vivo, but may play a small role in the ileum and colon.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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4-Aminobenzoic Acid / administration & dosage
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4-Aminobenzoic Acid / pharmacology
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5-Methoxytryptamine / administration & dosage
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5-Methoxytryptamine / pharmacology
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Animals
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Benzamides / administration & dosage
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Benzamides / pharmacology
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Blood Pressure / drug effects
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Bridged Bicyclo Compounds / administration & dosage
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Bridged Bicyclo Compounds / pharmacology
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Bridged Bicyclo Compounds, Heterocyclic*
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Cisapride
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Colon / drug effects
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Colon / metabolism
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Dioxanes / administration & dosage
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Dioxanes / pharmacology
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Dose-Response Relationship, Drug
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Heart Rate / drug effects
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Ileum / drug effects
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Ileum / metabolism
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Indoles / administration & dosage
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Indoles / pharmacology
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Intestinal Mucosa / drug effects
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Intestinal Mucosa / metabolism*
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Jejunum / drug effects
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Jejunum / metabolism
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Male
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Piperidines / administration & dosage
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Piperidines / pharmacology
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Rats
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Rats, Wistar
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Receptors, Serotonin / drug effects
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Receptors, Serotonin / metabolism*
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Serotonin / administration & dosage
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Serotonin / pharmacology*
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Serotonin Antagonists / pharmacology*
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Serotonin Receptor Agonists / pharmacology*
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Tropisetron
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para-Aminobenzoates
Substances
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Benzamides
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Bridged Bicyclo Compounds
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Bridged Bicyclo Compounds, Heterocyclic
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Dioxanes
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Indoles
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Piperidines
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Receptors, Serotonin
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Serotonin Antagonists
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Serotonin Receptor Agonists
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para-Aminobenzoates
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2-methoxy-4-amino-5-chlorobenzoic acid 2-(diethylamino)ethyl ester
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SB 204070A
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Serotonin
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5-Methoxytryptamine
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Tropisetron
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renzapride
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4-Aminobenzoic Acid
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Cisapride