Protective effect of verapamil on the cardiac and circulatory alterations induced by platelet-activating factor.
The role of calcium channels in the mediation of the cardiovascular effects of synthetic (1-O-octadecyl-2-acetyl-sn-glyceryl-3-phosphorylcholine) platelet-activating factor (PAF) was studied in vivo in the rabbit and in vitro in the coronary-perfused isolated heart and papillary muscle of the guinea pig following pretreatment with verapamil, a calcium antagonist. In the rabbit, verapamil (0.3 mg/kg) abrogated the ECG changes, and reduced all the hemodynamic alterations caused by PAF (0.8 microgram/kg). Verapamil (20 nmol) reduced both the electrical and mechanical alterations observed in the isolated heart and papillary muscle after the infusion of PAF (0.2 nmol). These results suggest that the transmembranal calcium channels play a crucial role in the mechanism by which PAF acts on the cardiovascular tissues.
D000818:Animals; D002319:Cardiovascular System / Q000187:drug effects*; D004562:Electrocardiography; D005260:Female; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects; D007473:Ion Channels / Q000187:drug effects*; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D010210:Papillary Muscles / Q000187:drug effects; D010972:Platelet Activating Factor / Q000037:antagonists & inhibitors*; D011817:Rabbits; D014700:Verapamil / Q000494:pharmacology*
D007473:Ion Channels; D010972:Platelet Activating Factor; D014700:Verapamil