BLOOD PRESSURE BLOOD FLOW AND OXYGENATION IN CLIPPED KIDNEY OF CHRONIC 2K1C RATS; EFFECTS OF TEMPOL AND ANGIOTENSIN BLOCKADE

摘要

Angiotensin II maintains renal cortical blood flow and renal oxygenation in the clipped kidney of early two-kidney, one clip Goldblatt hypertensive rats (2K,1C). The involvement of Ang II is believed to decline whereas oxidative stress increases during progression of 2K,1C hypertension. We investigated the hypothesis that the acute administration of drugs to inhibit reactive oxygen species (tempol) or angiotensin II type 1 receptors (candesartan) or angiotensin converting enzyme (enalaprilat), lower mean arterial pressure, and increase kidney blood flow and oxygenation in the clipped kidney of chronic 2K,1C rats in contrast to Sham controls. Twelve months after left renal artery clipping or Sham, mean arterial pressure, renal cortical blood flow and renal cortical and medullary oxygen tension were measured after acute administration of tempol followed by enalaprilat or candesartan followed by enalaprilatThe mean arterial pressure of the 2K,1C was reduced by candesartan (−9%), and more effectively by tempol (−35%). All applied treatments had similar blood pressure lowering effect in sham (average −21%). Only tempol increased cortical blood flow (+35%) and cortical and medullary oxygen tensions (+17% and +94%, respectively) in clipped kidneys of 2K,1C.Administration of enalaprilat had no additional effect, except for a modest reduction in cortical blood flow in the clipped kidney of 2K,1C when co-administered with candesartan (−10%).In conclusion, acute administration of tempol is more effective than candesartan in reducing the mean arterial blood pressure and improving renal blood perfusion and oxygenation in the clipped kidney of chronic 2K,1C rats.