Effects of aortic constriction and renal denervation in DOCA-hypertensive swine

Abstract

The autoregulation of renal blood flow (RBF) and glomerular filtration rate (GFR) was examined in normal and deoxycorticosterone acetate (DOCA)-hypertensive Yucatan miniature swine (YMS). Aortic constriction (AC) was used to vary renal perfusion pressure (RPP) from 158 to 90 mmHg for DOCA-YMS and 124 to 50 mmHg for normals. DOCA animals had calculated RBF autoregulatory indexes demonstrating less effective autoregulation compared with controls. Over the pressure range of RBF autoregulation, control animals also autoregulated their GFR, whereas most DOCA animals did not. When renal function in DOCA-YMS was evaluated at the normotensive RPP of 115 mmHg, GFR, urine volume, and sodium excretion were decreased by approximately 60, 70, and 80%, respectively. In DOCA-YMS, after the normalization of RPP to 115 mmHg, renal denervation significantly increased RBF. In DOCA animals the relative decrease in sodium and water excretion in relation to decreased RPP was not altered by renal denervation. In this hypertensive model the excretion of water and sodium are closely linked to RPP. At a normotensive RPP the sodium retention in the DOCA animals may be even further exaggerated by their inability to autoregulate GFR.