ROLE OF RENAL NERVES IN SODIUM DEPLETION-INDUCED SALT APPETITE

The ingestion of water and 0.3 M NaCl solution and the secretion of ke y hormones were studied in groups of intact and bilaterally renal-dene rvated rats after extracellular fluid depletion. Hypovolemia with mild hypotension was produced by subcutaneous injections of the diuretic f urosemide (10 mg/kg) followed by injections of the angiotensin-convert ing enzyme inhibitor captopril (5 mg/kg sc). Denervated rats drank sig nificantly less of a concentrated saline solution in response to deple tion than intact control rats did, but drank similar amounts of water. Denervated rats finished testing in significantly greater negative wa ter and sodium balance compared with controls. Renal denervation did n ot impair the secretion of renin and aldosterone or the formation of a ngiotensin I. The diminished sodium intake of denervated rats is not a ttributable to reduced water and sodium excretion in response to the h ypovolemic protocol. These results indicate that the integrity of the renal nerves is important for the normal elaboration of salt appetite in response to hypovolemia/hypotension.