Sodium chloride suppression of renin release in the unanesthetized rat.

Previous studies have shown that increased sodium chloride in drinking water failed to suppress serum renin activity (SRA) in the etheranesthetized rat. In the absence of anesthesia, sodium chloride decreased SRA by 76% and serum aldosterone by 72%. Deoxycorticosterone acetate, when given alone, produced similar results but was more effective in reducing SRA (96%) when combined with sodium chloride. However, if "light" ether anesthesia was administered prior to blood collection, there was a 10-fold increase in SRA and the effects of sodium chloride were blocked. Thus, in the absence of anesthesia, the renin-angiotensin-aldosterone system of the rat responds, as in other species, to a sodium load.