The relationship of the renal vascular activity of angiotensin II to the autonomic nervous system.

Abstract

In dogs anesthetized with chloralose the effects of angiotensin II on renal blood flow measured by rotameters were related to autonomic nervous factors. The effect of angiotensin II upon the renal vasculature is dependent upon intactness of autonomic innervation of the kidney, and a local effect that may have an autonomic nervous determinant either in terms of a critical store of sympathetic neurotransmitter or cholinergic involvement in the vascular effect of angiotensin II. Interruption of autonomic nervous activity by renal denervation and cervical cord section will reduce or abolish the renal vascular reactivity to angiotensin II. The effect of autonomic blocking agents on renal vascular reactivity to angiotensin II was predicted according to their activity at the neuroeffector site. Those agents, guanethidine, bretylium, and hydralazine, which influence sympathetic nervous activity by reducing the release of the neurotransmitter, block the renal vascular activity of angiotensin II; those agents that primarily block receptor sites (phentolamine) or influence ganglionic transmission (hexamethonium) are without effect on the renal vascular response to angiotensin II. The restoration by tyramine of the renal vascular response to angiotensin II suggests the participation of a particular store of sympathetic neurotransmitter in the vascular activity of angiotensin n.