Reactive oxygen species as important determinants of medullary flow, sodium excretion and hypertension.

Reactive oxygen species as important determinants of medullary flow, sodium excretion and hypertension. Am J Physiol Renal Physiol. 2014 Oct 29;:ajprenal.00455.2014 Authors: Cowley AW, Abe M, Mori T, O'Connor PM, Ohsaki Y, Zheleznova NN Abstract The physiological evidence linking the production of superoxide, hydrogen peroxide,and nitric oxide in the renal medullary thick ascending limb of Henle to regulation of medullary blood flow, sodium homeostasis, and long term control of blood pressure is summarized in this review. Data obtained largely from rats indicate that experimentally induced elevations of either superoxide or hydrogen peroxide in the renal medulla result in reduction of medullary blood flow, enhanced Na+ reabsorption and hypertension. A shift in the redox balance between nitric oxide and reactive oxygen species (ROS) is found to occur naturally in the Dahl salt-sensitive (SS) rat model where selective reduction of ROS production in the renal medulla reduces salt-induced hypertension. Excess medullary production of ROS in SS rats emanates from the medullary thick ascending limbs of Henle (both from the mitochondria and membrane NAD(P)H-oxidases) in response to increased delivery and reabsorption of excess sodium and water. There is evidence that ROS and perhaps other mediators such as ATP diffuse from the mTAL to surrounding vasa recta capillaries resulting in medullary ischemia which thereby contributes to the hyperten...
Source: Am J Physiol Renal P... - Category: Urology & Nephrology Authors: Tags: Am J Physiol Renal Physiol Source Type: research