The actions of 5-hydroxytryptamine and histamine on the isolated ileum of the tree shrew (Tupaia glis).
1. Contractions to 5-hydroxytryptamine (5-HT) and histamine of longitudinal muscle from the isolated ileum of the tree shrew (Tupaia), guinea-pig and rat were investigated by constructing dose-response curves and studying the effects of various antagonists. 2 In the Tupaia and rat ileum the contraction to 5-HT was reduced by methysergide but not affected by tetrodotoxin (TTX), morphine, hexamethonium (C6) or atropine. The response of guinea-pig ileum to 5-HT was not significantly inhibited by methysergide or C6, but was blocked by TTX, morphine and atropine. 3 Histamine-induced contraction of Tupaia and guinea-pig ileum was antagonized by diphenhydramine but not by TTX, morphine, C6 or atropine. Histamine was almost without effect on the rat ileum.
D000818:Animals; D006168:Guinea Pigs; D006632:Histamine / Q000494:pharmacology*; D006634:Histamine H1 Antagonists / Q000494:pharmacology; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D051381:Rats; D012701:Serotonin / Q000494:pharmacology*; D013045:Species Specificity; D011443:Strepsirhini / Q000502:physiology*; D014418:Tupaiidae / Q000502:physiology*
D006634:Histamine H1 Antagonists; D012701:Serotonin; D006632:Histamine