title: Effect of platelet activating factor on guinea-pig papillary muscle.
abstract: Platelet activating factor (PAF) induces a biphasic effect on guinea-pig papillary muscle: 1. a transient positive inotropic effect preceded by an increase in action potential duration (APD); 2. a marked negative effect on inotropism and on APD. Since Ca++ slow action potentials were initially enhanced by PAF and then markedly depressed, it is suggested that PAF specifically interferes with the Ca++ slow channel.
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002118:Calcium / Q000502:physiology; D006168:Guinea Pigs; D007473:Ion Channels / Q000187:drug effects; D009200:Myocardial Contraction / Q000187:drug effects*; D010210:Papillary Muscles / Q000187:drug effects*; D010972:Platelet Activating Factor / Q000494:pharmacology*
chemical_list: D007473:Ion Channels; D010972:Platelet Activating Factor; D002118:Calcium