Effect of Vasopressin Blockade on Blood Pressure in Conscious Rats with Malignant Two-Kidney Goldblatt Hypertension

The role of vasopressin (VP) in maintaining blood pressure in malignant two-kidney one-clip Goldblatt hypertension in chronically catheterized conscious rats was investigated by studying the effect of two structurally different VP pressor antagonists. Injections of either 20 µg/kg of dPTyr(Me)AVP or 10 µg/kg of d(CH₂)₅Tyr(Me)AVP failed to alter mean arterial pressure or heart rate, although both antagonists completely inhibited the pressor response elicited by exogenous VP. These results suggest, that VP is not involved as a pressor hormone in the maintenance of high blood pressure in this type of experimental hypertension.