[Effect of prostaglandins E1 and E2 on the internal carotid artery].

Experiments were conducted on the dog internal carotid artery (with circulatory isolation); the following peculiarities of the effects of the prostaglandins (PG) under study were revealed: PG-E1 caused either a constrictory or a dilatory effect, and PG-E1--a constrictory effect only; in the former case the artery became accustomed with repetition of the action, and in the latter case it did not become accustomed. The duration of the PG-E2 effects, particularly of relaxation, was much greater than of the serotonin effects; residual contraction of the vascular smooth muscles was frequent; PG-E1 and PG-E2 intensified the effects of serotonin, and, partially, of noradrenaline.