title: Differences in contractile responses to acetylcholine and serotonin in rat stomach fundus strips.
abstract: The differences in contractile responses to acetylcholine (ACh) and serotonin (5-HT) were studied in the rat fundus strips. At low temperatures, the contractile response to 5-HT was reduced more noticeably than to ACh. The contraction induced by ACh at 4 degrees C was not inhibited by La3+. Removal of extracellular Ca2+ reduced the response to 5-HT more significantly than that to ACh.. La3+, verapamil and D-600 inhibited the 5-HT response more than the ACh response. In Ca2+-free solution the contractile response to ACh of a fundus strip preloaded with Ca2+ was lar ger than that to 5-HT. These results suggest that the Ca2+ movements induced by ACh and by 5-HT are different, and that the difference in Ca2+ movements may cause the difference in contractile responses to the two agonists at low temperatures.
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D005711:Gallopamil / Q000494:pharmacology; D066298:In Vitro Techniques; D007811:Lanthanum / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D012701:Serotonin / Q000494:pharmacology*; D013270:Stomach / Q000187:drug effects; D013696:Temperature; D014700:Verapamil / Q000494:pharmacology
chemical_list: D012701:Serotonin; D005711:Gallopamil; D007811:Lanthanum; D014700:Verapamil; D000109:Acetylcholine; D002118:Calcium