Cardiovascular effects of budralazine in the dog.

Cardiovascular effects of budralazine were investigated in isolated and cross-circulated dog atrial preparations. When budralazine was injected into the jugular vein of the donor dog, a hypotension was produced with slight tachycardia in a dose-related manner. At the same time, slight positive chronotropic and biphasic inotropic effects were induced in the isolated atrium perfused with donor's arterial blood. When budralazine was injected into the cannulated sinus node artery of the isolated atrial preparation, it produced only slight negative chronotropic and inotropic responses, occasionally followed by positive responses. Vehicle injections induced monophasic negative chronotropic and inotropic effects. It is concluded that budralazine has a potent vasodilator action, a reflex-induced sympathomimetic action, but no direct cardiac stimulating properties. Moreover, a direct catecholamine releasing action of budralazine does not appear to be prominent.