The Renin-Angiotensin System and Thirst: A Reevaluation. II. Drinking Elicited in Rats by Caval Ligation or Isoproterenol.

Abstract

Ligation of the inferior vena cava and administration of isoproterenol stimulate renin secretion and augment water intake in rats. The present experiments suggested that the plasma renin activities produced by these treatments do not account for more than 20% of the observed drinking behavior. Direct measurements of arterial blood pressure further indicated that nephrectomized rats go into hypotensive shock after caval ligation or isoproterenol treatment. Drinking was elicited in these hypotensive animals by systemic injection of hypertonic NaCl solution, renin, or Pitressin, or by intracranial injection of angiotensin, but in each case a rapid increase in blood pressure also was observed. It appears that nephrectomy reduces water intake in these animals by undermining their general capacity to behave rather than by removing a specific dipsogenic stimulus. Drinking elicited in rats by caval ligation or isoproterenol apparently is not mediated by the renin-angiotensin system.