Contribution of vascular and tubular effects of arginine-vasopressin to the development of deoxycorticosterone acetate (DOCA)-salt hypertension in rats

The role of arginine-vasopressin (AVP) in the pathogenesis of deoxycorticosterone acetate (DOCA) salt hypertension in rats was studied with AVP receptor antagonists for its tubular (V2) and/or vascular (V1) actions. When chronic (six weeks) infusion of the antagonists was started concomitantly with DOCA-salt treatment the development of hypertension was attenuated by the V1-antagonist and prevented by the V1V2-antagonist. However, the V1V2-antagonist induced severe and persistent hypernatraemia in all rats. When chronic (two weeks) infusion of the antagonists was started in rats with established hypertension after five weeks of DOCA-salt treatment blood pressure was not influenced by the V1-antagonist. The rats which received the V1V2-antagonist died from hypernatraemia within four days. These results suggest that in DOCA-salt treated rats AVP is essential for the prevention of severe and life-threatening hypernatraemia. AVP appears to contribute significantly to the development of this form of hypertension through both its vascular and tubular effects.