Pharmacological characterization of 5-hydroxytryptamine-induced motor activity (in vitro) in the guinea pig gastric antrum and corpus

摘要: In order to characterize the receptor subtypes involved in 5-hydroxytryptamine (5-HT)-induced circular muscle motor responses of guinea pig gastric antrum and corpus, we examined effects several antagonists vitro. 5-HT evoked concentration-dependent contractions relaxations corpus. 5-HT-induced antral were abolished by pretreatment with atropine tetrodotoxin. Methysergide, ketanserin, granisetron [1-[2-(methylsulphonylamino)ethyl]-4-piperidinyl]methyl 1-methyl-1H-indole-3-carboxylate maleate salt (GR113808A), but neither 1-(2-methoxyphenyl)-4-[4-(2-phthalimido)butyl]piperazine (NAN-190) nor N2-[(4R)-4-hydroxy-1-(1-methyl-1H-indol-3-yl)carbonyl-l-prolyl]-N-methyl-N-phenylmethyl-3-(2-naphthyl)-l-alaninamide (F inhibited (3 × 10−6 M: submaximal concentration)-induced concentration dependently shifted concentration-response curve right. M)-induced corporal relaxation was not affected tetrodotoxin, or GR113808A. At 10−7 M, methysergide NAN-190 relaxation, at a high (10−6 M) they both it We conclude that contraction is mediated cholinergic neurons via 5-HT2A, 5-HT3 5-HT4 receptors, whereas 5-HT1-like receptors on smooth are sensitive NAN-190.