PROTECTION FROM HYPOXEMIC RENAL DYSFUNCTION BY VERAPAMIL AND MANGANESE IN THE RABBIT

The ability of calcium channel blockers to prevent and/or to reverse t he hypoxemia-induced renal dysfunction was studied in anesthetized and mechanically-ventilated rabbits. Renal blood flow (RBF) and glomerula r filtration rate (GFR) were determined by para-aminohippuric acid and inulin clearance, respectively. Each animal was considered as its own control. In 9 rabbits (group 1), verapamil infusion, 1 mu g.kg(-1).mi n(-1), did not change basal renal hemodynamics. In a second group (n = 9), hypoxemia induced marked significant decreases in GFR, RBF and ur ine flow rate (-22 +/- 5%, -18 +/- 6% and -34 +/- 7% respectively). Th e administration of verapamil partially reversed the hypoxemia-induced renal dysfunction. Likewise, hypoxemia did not induce any change in r enal function in verapamil pretreated rabbits (n = 8). This study show s that verapamil is able to prevent and to partially reverse the adver se effects of hypoxemia on renal hemodynamics. The intrarenal infusion of manganese chloride, another calcium channel blocker, was also effe ctive in blunting the hypoxemia-induced changes in the left infused ki dney, but not in the contralateral kidney. The overall results demonst rate that a significant protection from hypoxemic renal dysfunction ca n be achieved by inhibitors of calcium ion transport.