Effect of brain-stem stimulation on renal function

¹ Division of Neurological Surgery and the Department of Physiology, University of California Medical Center, San Francisco, California

The effect of stimulation of the hypothalamus, midbrain, pons and medulla oblongata on renal excretion of water, sodium and potassium and on glomerular filtration rate has been determined in 26 pentobarbital anesthetized dogs with chronically implanted electrodes. The effect of renal denervation on the stimulation responses has been determined in 12 animals. Stimulation of 15 points in the dorsal medulla just lateral to the mid-line led to a rise in blood pressure and an associated fall in creatinine clearance and urine volume. The renal changes were blocked by renal denervation. Stimulation of six points located in and near the area postrema led to a rise in creatinine clearance and urine volume without a significant change in systemic blood pressure. Stimulation of two points in the pons led to increases in sodium excretion without a detectable change in glomerular filtration rate. Stimulation of three points in the midbrain led to a decrease in creatinine clearance, but stimulation of 39 points elsewhere in the medulla, pons, midbrain and posterior hypothalamus had no effect on glomerular filtration rate and water and electrolyte excretion, even though changes in blood pressure did occur with some of these stimuli.