EFFECT OF SYMPATHETIC BLOCKING-AGENTS ON ANTINATRIURESIS OF REFLEX RENAL NERVE-STIMULATION

Abstract

To evaluate the effects of reflex renal sympathetic nerve stimulation on renal tubular Na handling, clearance studies were performed in anesthetized dogs. With renal perfusion pressure held constant, baroreceptor reflex renal sympathetic nerve stimulation was produced by controlled arterial hemorrhage or carotid sinus perfusion. Significant decreases in urinary Na excretion occurred in the presence of minor insignificant alterations in renal blood flow and no changes in glomerular filtration rate. Renal .alpha. adrenergic receptor blockade (phenoxybenzamine) or adrenergic blockade (guanethidine) completely reversed the fall in urinary Na excretion; this could not be attributed to alterations in glomerular filtration rate or renal blood flow. These stdies support the interpretation that adrenergic innervation of the renal tubules is involved in the regulation of renal tubular Na reabsorption.