THE EFFECT OF PROSTAGLANDIN E1 ON RESPONSES OF SMOOTH MUSCLE TO CATECHOL AMINES, ANGIOTENSIN AND VASOPRESSIN.

Reduction of the pressor responses to adrenaline in the rabbit following administration of prostaglandin E(1) has been confirmed. The effect is, however, nonspecific since noradrenaline, angiotensin and vasopressin are also antagonized. Analogous responses were observed in blood flow experiments on the cat hind limb but not on the rabbit isolated auricles or the rabbit isolated duodenum. Contractions of the cat nictitating membrane produced by sympathetic preganglionic stimulation or by adrenaline were not decreased following injection of prostaglandin E(1) but the relaxation period was shorter. Contractions of the rabbit vas deferens induced in vivo by adrenaline were smaller after prostaglandin E(1) and this effect tended to be long-lasting.