Effects of renal denervation on arterial baroreceptor function in Goldblatt renovascular hypertension

Sympathetic nerve activity is increased in renovascular hypertension. Renal denervation has shown promise in the treatment of patients with resistant hypertension to drug therapy, although the mechanisms underlying reduction in blood pressure remains uncertain. The aim of this study was to evaluate the effects of unilateral renal denervation (H+DnX) in efferent post-ganglionic sympathetic nerve activity and arterial baroreceptor reflex sensitivity to renal (rSNA) and lumbar (lSNA) sympathetic nerves in Goldblatt hypertensive rats (2K1C). The baroreceptor sensitivity to heart rate (HR) was also evaluated. Denervation of clipped kidney (DnX – all visible bundles nerves were dissected – 10% phenol) was performed 5 weeks after clipping (gap width 0.2mm). The rSNA and barorreceptor reflex control to rSNA was performed in the innervated contralateral kidneys. Ten days after DnX, blood pressure (BP) was significantly reduced (16%) in the 2K1C rats compared to 2K1C undenervated (H). DnX normalized rSNA (C:109±7,n=14; H:150±8,n=12; H+DnX:89±7, pps n=8) and lSNA (C:68±5,n=8; H:105±7,n=12; H+DnX:54±4, pps n=9) in the 2K1C rats. DnX significantly improved the baroreceptor function for rSNA (gain in 20mmHg variation=C:-2.7±0.3, n=11; H:-0.9±0.1, n=7; H+DnX:-1.7±0.2, pps/mmHg n=7) and bradycardic response (C:-2.5±0.1, n=7; H:-1.6±0.07, n=5; H+DnX:-2.6±0.2, bpm/mmHg n=3), but not for lSNA in 2K1C rats. The results show that renal denervation normalized sympathetic vasomotor activity accompanied by a non uniform improvement in the arterial baroreceptor function. Whether the baroreceptor function sensitivity improvement induced by DnX is a cause or a consequence of BP reduction remains to be determined. FAPESP and CAPES.