Effects of Calcium Antagonists on Coronary Spasm and Pulmonary Artery Contraction in Comparison to Their Antagonistic Action against K-Strophanthin in Isolated Guinea Pig Atria

Abstract

The contraction of the K+ depolarized pulmonary artery of the guinea pig was diminished by the Ca2+ antagonists nifedipine, gallopamil, diltiazem, verapamil and prenylamine (listed in order of activity). 45Ca uptake of the depolarized pulmonary artery was reduced by nifedipine, verapamil and prenylamine (in this order of activity). The depression of the coronary flow of the isolated guinea pig heart, brought about by BaCl2, antigenic rabbit serum or vasopressin plus oxytocin was reduced by infusion of prenylamine. The positive inotropic effect of K-strophanthin on the isolated, electrically stimulated left atrium of the guinea pig heart was reduced by gallopamil, verapamil, prenylamine, diltiazem and nifedipine (in this order of activity).