Effect of bromocriptine on cardiac function and coronary blood flow.
The present study was designed to investigate the effects of bromocriptine, a dopamine receptor agonist, on systemic and coronary hemodynamics and to determine the mechanisms involved in the action of this compound. Intravenous infusion of bromocriptine (1 microgram/kg/min for 20 min) to pentobarbital-anesthetized dogs produced significant decreases in blood pressure, heart rate, total peripheral resistance, peak dP/dt, left ventricular pressure, and coronary blood flow. There were significant increases in stroke volume and coronary vascular resistance, whereas the index of contractility was unaffected. Cardiac output was decreased 30 min after the termination of bromocriptine infusion. The cardiovascular actions of bromocriptine were significantly antagonized by the dopamine receptor antagonist, sulpiride. Bromocriptine also failed to exert these effects when administered to animals that were treated with ganglionic blocking agents. These results suggest that the hypotensive action of bromocriptine is mainly due to a decrease in total peripheral resistance. In addition, the actions of bromocriptine on cardiac function are the result of activation of presynaptic dopamine receptors and the drug does not have any direct action on the myocardium.
D000818:Animals; D001971:Bromocriptine / Q000494:pharmacology*; D003326:Coronary Circulation / Q000187:drug effects*; D004285:Dogs; D005260:Female; D006321:Heart / Q000187:drug effects*; D006439:Hemodynamics / Q000187:drug effects; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D011954:Receptors, Dopamine / Q000187:drug effects
D011954:Receptors, Dopamine; D001971:Bromocriptine