Selective Vasodilation Produced by Renal Denervation in Adult Spontaneously Hypertensive Rats

The kidneys of adult male spontaneously hypertensive rats (SHR) were denervated, and systemic and regional blood flows were measured 3 to 5 ours or 5 days after denervation. Arterial pressure was reduced 20 to 27% in denervated SHR during both periods compared with that in shamoperated SHR (iliolumbar blood vessles painted with phenol). This hypotnsive response was produced by a 32 to 35% reduction in total peripheral resistance. At 3 to 5 hours and at 5 days, a major decrease in total peripheral resistance was produced by vasodilation in the kidneys and splanchnic organs. Acute urine output, sodium excretion, and plasma renin activity in response to a saline load were not different between sham-operated and denervated SHR. The decreased toal peripheral resistance in denervated SHR may have been secondary to a decreased central sympathetic nerve activity revealed by a decreased maximum response to ganglionic blockade. The results suggest that a pathophysiolgical link may exist between the kidneys and splanchnic organs in genetic hypertension and that specific efferent antiadrenergic or antiafferent nerve therapy, or both, in the kidney may lead to substantial specific decreases not only in renal vascular resistance but also in splanchnic vascular resistance and total peripheral resistance.