Central baroreflex regulation by the renal nerves in anesthetized rats.

To determine whether the renal nerves affect central baroreflex regulation, the aortic depressor nerve (ADN) was stimulated electrically, while blood pressure, heart rate, and splanchnic nerve activity were recorded in renal denervated and sham-operated rats anesthetized with urethane. Tail cuff systolic pressure fell 6 days after renal denervation, but mean blood pressure recorded after anesthetizing with urethane did not differ between renal denervated and sham-operated rats. Urinary sodium excretion was greater in renal denervated than in sham-operated rats. ADN stimulation produced frequency-dependent falls in blood pressure accompanied by inhibitions of sympathetic nerve activity and heart rate. Depressor and sympathetic inhibitory responses to ADN stimulation were significantly smaller in renal denervated than in sham-operated rats. These findings suggest that the renal nerves can regulate baroreflexes centrally.