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标题：Pharmacological Characterization of 5-Hydroxytryptamine-Receptor Subtypes in Circular Muscle from the Rat Stomach
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作者：Tohru Komada ; Shingo Yano
期刊名称：Biological and Pharmaceutical Bulletin
印刷版ISSN：0918-6158
电子版ISSN：1347-5215
出版年度：2007
卷号：30
期号：3
页码：508-513
DOI：10.1248/bpb.30.508
出版社：The Pharmaceutical Society of Japan
摘要：5-Hydroxytryptamine (5-HT) modulates gastric motility and gastric emptying via a variety of 5-HT receptor subtypes. However, regional and functional differences among 5-HT receptor subtypes in the rat stomach are not fully investigated. Thus, we aimed to characterize 5-HT receptor subtypes involved in the 5-HT-induced contractions in the isolated antral, corporal and fundic circular muscles of the rat stomach by measuring the contractile force. 5-HT induced concentration-dependent contractions in the antrum, corpus and fundus. 5-HT-induced antral contractions were partly blocked by atropine and enhanced by tetrodotoxin (TTX). Neither atropine nor TTX affected the corporal or the fundic contractions to 5-HT. In the antrum, 5-HT-induced contractions were inhibited by methysergide, tended to be inhibited by ketanserin, enhanced by SB-203186, but were not affected by WAY-100635, GR127935, RS-127445, ondansetron, or SB-269970. In the corpus, 5-HT-induced contractions were inhibited by ketanserin or methysergide. In the fundus, 5-HT-induced contractions were blocked by methysergide or RS-127445, but were enhanced by cinanserin or SB-203186. It is thus concluded that contractile responses to 5-HT in the antrum are mediated by 5-HT receptors on both smooth muscle and neurons whilst in the corpus and fundus responses are mainly mediated by 5-HT receptors on smooth muscle. Moreover, the antrum presents the contractile 5-HT_2A and 5-HT_2B receptors and the relaxant 5-HT₄ receptors. The corpus presents the contractile 5-HT_2A receptors, and the fundus presents the contractile 5-HT_2B receptors and the relaxant 5-HT_2A and 5-HT₄ receptors.
关键词：5-hydroxytryptamine (5-HT);5-HT receptor antagonist;rat stomach;circular muscle;contraction;relaxation