Effect of Ca++ channel blockers and saralasin on angiotensin II induced contraction in rabbit aortic strip.

To investigate the role of calcium in angiotensin II (A II) induced contractions in rabbit aortic strip, the action of verapamil, nifedipine, cinnarizine and saralasin was studied. The cumulative dose response curves obtained with A II shifted to right with increasing concentrations of all these four agents. The antagonism was noncompetitive. The pD'2 value of saralasin was 8.49 of nifedipine, 8.15 and or verapamil 7.92. Cinnarizine which mainly acts at intracellular site had pD'2 value 5.54. The results indicate that A II induced contractions critically depend on entry of calcium through channels which appear to be closely associated with angiotensin receptors.