Pathogenesis of one-kidney, one-clip hypertension in rats after renal denervation

Abstract

This study examines the role of the renal nerves in the chronic and early developmental stages of one-kidney, one-clip (1K-1C) Goldblatt hypertension. Groups of uninephrectomized Sprague-Dawley rats underwent renal artery constriction with a clip of an internal diameter of 0.23 mm (groups 1 and 3) or 0.40 mm (groups 2 and 4) to produce severe or moderate hypertension. Two weeks later, groups 1 and 2 were subjected to renal denervation and groups 3 and 4 were denervated 6 and 7 wk after clipping, respectively. In all four groups, hypertension remained unchanged during the subsequent 2 wk after denervation. To study further the effects of renal denervation during the early onset of hypertension, groups 5, 6, and 7 received the smaller (0.23 mm) clip after uninephrectomy. Groups 5 and 6 were renal denervated immediately before clipping; group 7 was not denervated. In groups 6 and 7 the renin-angiotensin system was blocked with a continuous infusion of the converting-enzyme inhibitor captopril for 24 h before and 15 days after clipping. In group 5, renal denervation did not prevent a prompt and severe rise in the systolic blood pressure. In groups 6 and 7, infusion of captopril prevented the hypertension only during the first 4 days after clipping; at no time was there a difference in the systolic blood pressure curves of groups 6 and 7 during or after captopril infusion. These data demonstrate that regardless of the severity and duration of hypertension, renal denervation failed to attenuate either the development or the maintenance of 1K-1C Goldblatt hypertension in the rat. Thus the present results fail to provide support for the concept that the renal nerves modulate the hypertension in this experimental model.