Hoe 263, a new substance with calcium channel antagonistic activity

Hoe 263 inhibited the contraction of the potassium-depolarized pulmonary artery of the guinea pig. In this experiment it was slightly more active than verapamil. The calcium uptake of the potassium-depolarized pulmonary artery was inhibited by Hoe 263 more effectively than by prenylamine. The upstroke velocity of the potassium-depolarized papillary muscle of the guinea pig was depressed with similar concentrations of Hoe 263 and verapamil. In the (3H)-nitrendipine binding test, Hoe 263 was effective at similar concentrations as prenylamine and verapamil. The positive inotropic effect of K-strophanthin was depressed by Hoe 263 at concentrations which were comparable with those necessary for verapamil.