[Role of afferent renal nerves in 2K2C Goldblatt hypertension].

ABSTRACT

In order to study the role of afferent renal nerves in 2K2C Goldblatt hypertension, the renal afferent nerves were selectively lesioned by bilateral T9-L2 spinal dorsal rhizotomy before clipping (internal diameter, 0.3 mm) of birenal arteries. Systolic blood pressure of the rat was measured by tail-cuff method. Concentrations of catecholamines, Ang II, and aldosterone were determined respectively by HPLC-EC and RIA, and vascular structural changes were measured by blood vessel micro-image analysis system coupled with a computer. The results showed that the concentrations of NE and E in medulla oblongata, adrenal gland and plasma, and of plasma Ang II and aldosterone as well as body weight of the rat were all significantly increased. The heart coefficient (heart wt/body wt), the media thickness, and the media thickness/lumen diameter in superior mesenteric arteries were also increased in 2K2C hypertensive rats (clipping, 6 wk) as compared with those in control rats. Bilateral rhizotomy delayed development of 2K2C hypertension and prevented above-mentioned vascular structural changes, the NE and E concentrations of medulla oblongata, adrenal gland and plasma were all decreased, hypothalamic NE and E were increased, and plasma Ang II level was not significantly changed. These results suggest that afferent renal nerves may play a partial role in the development of hypertension in 2K2C rats by activating sympathetic nervous system as a result of affecting metabolic activities of brain catecholaminergic neurons, and that high-plasma Ang II and aldosterone as well as heart hypertrophy and proliferation of vascular smooth muscle cells may also participate in the pathogenesis of hypertension in 2K2C rats.