title: Characteristics of 5-hydroxytryptamine receptors involved in contraction of feline ileal longitudinal smooth muscle.
abstract: A number of studies have demonstrated that 5-hydroxytryptamine (5-HT) can induce muscle contraction or relaxation response and enhance secretion in the gastrointestinal tract via a multiplicity of 5-HT receptor subtypes. In the present study, we investigated the pharmacological characterization of the 5-HT-induced contractile response in longitudinal smooth muscle isolated from the feline ileum. Addition of 5-HT into muscle chambers enhanced the basal tone and spontaneous activity in a concentration-dependent manner. The neurotoxin tetrodotoxin did not alter the 5-HT-induced contraction of the longitudinal muscles. Neither atropine nor guanethidine affected the contraction. The 5-HT agonists, 5-methylserotonin hydrochloride and mosapride, also evoked concentration-dependent contractions. The 5-HT-induced contraction was enhanced by the 5HT(2) receptor antagonist ketanserin and the 5-HT(3) receptor antagonist ondansetron but was inhibited by the 5-HT(1) receptor antagonist methysergide and 5-HT(4) receptor antagonist GR113808. These results indicate that 5-HT(1) and 5-HT(4) receptors may mediate the contraction of the 5-HT-induced response and 5-HT(2) and 5-HT(3) receptors may mediate 5-HT-induced relaxation in feline ileal longitudinal smooth muscles.
authors: Department of Pharmacology, College of Pharmacy, Chung-Ang University, Seoul 156-756, Korea.
authors: Yiyi
authors: Y
authors: Wang
authors: Sun Young
authors: SY
authors: Park
authors: Kyung Hoon
authors: KH
authors: Oh
authors: Youngsil
authors: Y
authors: Min
authors: Yun-Jeong
authors: YJ
authors: Lee
authors: Seok-Yong
authors: SY
authors: Lee
authors: Uy Dong
authors: UD
authors: Sohn