Inhibition of Adenosine-induced Coronary Vasodilatation

Abstract

Isolated spontaneously beating rat and guinea-pig hearts were used to investigate the direct dilator action of adenosine (5 μg./ml.) on the coronary vasculature. Phenoxybenzamine (10 μg./ml.) blocked the coronary dilator effect of adenosine and of another coronary dilator drug, dipyridamole, but failed to block adenosine-induced bradycardia. These results are interpreted to mean that adrenergic receptors may be involved in the coronary-dilator effect of adenosine.