Intrarenal and sympathetic premotor neuron changes in response to denervation of ischemic kidney in renovascular hypertension

Abstract

AT1R upregulation in the rostral ventrolateral medulla (RVLM) contributes to sympathoexcitation and arterial hypertension in the 2‐kidney,1‐clip (2K1C) model. Our aim was to investigate whether afferent and efferent renal sympathetic nerves play a role in the modulation of Ang II receptors expression in the central nuclei (RVLM and PVN) and renal lesion markers in renovascular hypertension. Renal denervation of clipped kidneys (DnX: visible bundles were dissected + 10% phenol) was performed in Wistar male rats (n=5/group) 4.5 weeks after clipping. Ten days after DnX the mean arterial pressure was significantly (p<.05) reduced (202 ± 6 vs 178 ± 9 mmHg) in the 2K1C rats. The AT1R was upregulated in the RVLM (73%) and PVN (43%) in the 2K1C group, DnX normalized these expressions in both nuclei. The AT2R expression was increased in the RVLM (76%) and PVN (76%) of 2K1C group and DnX reduced AT2R in both regions. Renal lesion was characterized by cortical interstitium α‐smooth muscle actin (α‐SMA) immunohistochemical expression. The α‐SMA expression was augmented in the clipped (67 fold) and nonclipped (127 fold) kidneys and DnX significantly reduced α‐SMA in both kidneys (9 and 25 fold, respectively) of 2K1C rats. DnX produced no changes in control rats. Thus, our data show that renal nerves may modulate Ang II receptors in the RVLM and PVN and contribute to renal lesion in the renovascular hypertension.Supported by FAPESP and CNPQ