EFFECTS OF VAGOTOMY AND RENAL DENERVATION ON RENAL RESPONSE TO BLOOD VOLUME EXPANSION

Abstract

In anesthetized dogs infusion of "artificial blood" caused an initial natriuresis associated with increased glomerular filtration and solute diuresis often supplemented later by an abrupt decrease of free-water reabsorption. A second infusion produced a larger response of similar pattern except for an earlier increase in solute output and often a concurrent decrease in free-water reabsorption. In other dogs with chronic unilateral renal denervation, cervical vagotomy was carried out between successive infusions. The renal responses on the innervated side were not different, before or after vagotomy, from those in intact dogs, implying that vagal afferents did not contribute essentially to the reaction to this type of blood volume expansion. The increase in glomerular filtration rate observed in the denervated kidney after the first infusion could not have been due to a withdrawal of renal sympathetic tone. The patterns of response to infusions, before and after vagotomy, were also not different in innervated and denervated kidneys, but the magnitude of the second diuresis and natriuresis was less on the denervated side. It is suggested that a reduced vascular reactivity of the denervated organ to a humoral effector mechanism could account for its depressed response to a second infusion in relation to that on the innervated side.