Effects of afferent renal nerve stimulation on renal hemodynamic and excretory functions.

In anesthetized cats (n = 9) renal afferent fibers were electrically stimulated for 11 min, and the response of the contralateral innervated kidney was compared with that of the ipsilateral denervated one. Before stimulation, renal blood flow, glomerular filtration rate, and water and sodium excretions were significantly lower in the innervated kidney than in the denervated one. Afferent renal nerve stimulation augmented arterial pressure and also increased sodium and water excretions from both kidneys without concomitant changes in glomerular filtration rates and renal blood flows. Absolute and percent changes in sodium and water excretions from the innervated kidney were similar to those observed in the denervated one. The same results were obtained in cats (n = 4) which underwent bilateral adrenalectomy to avoid the effect of circulating catecholamines. In another group of cats (n = 5), the increase in renal perfusion pressure due to the stimulation was prevented by an aortic snare: this resulted in a slight but equal decrease of all variables in both kidneys. These experiments do not show a reflex control of renal function from renal afferents.