Dissociation of inotropic and chronotropic effects of isoproterenol on the isolated working rat heart after coronary artery ligation.
Acute regional ischemia was achieved by left coronary artery ligation in the isolated working rat heart preparation. After an early decline in left ventricular performance, the preparation showed good mechanical stability. Electrical stimulation beyond 5.5--5.7 stimuli/sec had a negative inotropic effect. When dl-isoproterenol was added to the perfusion fluid aortic output showed a biphasic response but left ventricular peak systolic pressure rose to preligation values as heart rate reached 400 beats/min, suggesting dissociation of inotropic and chronotropic effects in these experimental conditions.
D000818:Animals; D001783:Blood Flow Velocity; D001794:Blood Pressure; D002302:Cardiac Output / Q000187:drug effects; D003331:Coronary Vessels / Q000502:physiology*; D006321:Heart / Q000502:physiology*; D006339:Heart Rate / Q000187:drug effects; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology*; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D010477:Perfusion; D051381:Rats; D013268:Stimulation, Chemical
D007545:Isoproterenol