title: Positive inotropic effect of acetylcholine in isolated human atrial fibers.
abstract: We studied the effects of acetylcholine on the transmembrane action potential and the contractile force of isolated human atrial fibers obtained at cardiac surgery. In 3 of 12 preparations, 10(-7)-10(-6) M acetylcholine induced a substantial increase in the contractile force following a brief initial decrease. Atropine diminished both the initial negative and the later positive inotropic effects induced by acetylcholine while propranolol abolished only the later effect.
mesh_terms: D000109:Acetylcholine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000200:Action Potentials / Q000187:drug effects; D001285:Atropine / Q000494:pharmacology; D002395:Catecholamines / Q000378:metabolism; D006325:Heart Atria / Q000187:drug effects*; D006801:Humans; D009200:Myocardial Contraction / Q000187:drug effects*; D011433:Propranolol / Q000494:pharmacology
chemical_list: D002395:Catecholamines; D001285:Atropine; D011433:Propranolol; D000109:Acetylcholine