Vasopressin potentiation of catecholamine actions in dog, rat, cat, and rat aortic strip

Abstract

This study was undertaken to determine whether arginine vasopressin, infused or injected in doses within known physiological ranges, can alter pressor responses to injected or endogenously liberated catecholamines. In 8 pentobarbital-anesthetized dogs, 14 pithed rats, and 7 spinal cats, the pressor responses to catecholamine injections were definitely potentiated by administration of nonpressor doses of vasopressin. In eight dogs anesthetized with N₂O-O₂, readily reproducible pressor responses to bilateral carotid artery occlusion were subsequently potentiated by infusions of vasopressin. Vasopressin also potentiated both isometric and isotonic responses of 37 rat aortic strip preparations to norepinephrine or epinephrine added to the Krebs-bicarbonate bath. Vasopressin, in physiological dose ranges, potentiates pressor responses to catecholamines by a direct rather than a central action. Endogenously liberated vasopressin may play a role in the responsiveness of vascular smooth muscle to endogenously liberated catecholamines in dog, rat, and cat.