Cinepazet relaxation of aortic strips from normal and spontaneously hypertensive rats

The vasodilator cinepazet (Vascoril) was tested for its ability to relax potassium-contracted aortic strips obtained from normal and spontaneously hypertensive rats (SHR). Cinepazet caused a dose-dependent relaxation of the isolated aortic strip preparations which had been contracted with 60 mM KCl. The ED50 for this relaxant effect was 200 microgram/ml. No differences in relaxation response to cinepazet were found between tissues from SHR and normal animals. The drug is 2 x 10(4) less potent than verapamil on a weight basis in this action on rat aortic tissue. The results suggest that the excitation-contraction mechanism associated with KCl-induced membrane depolarization is equally affected by cinepazet in aortae from SHR and WKY.