Mechanisms of salt-sensitive hypertension: role of renal medullary inducible nitric oxide synthase

Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi 39216 The goal of this study was to determine the role of renal medullary inducible nitric oxide synthase (iNOS) in the arterial pressure, renal hemodynamic, and renal excretory changes that occur in Dahl/Rapp salt-resistant (R) and salt-sensitive (S) rats during high Na intake. Forty R and S rats, equipped with indwelling arterial, venous, and renal medullary catheters, were subjected to high (8%) Na intake, and selective iNOS inhibition was achieved with continuous intravenous or renal medullary interstitial infusion of aminoguanidine (AG; 3.075 mg · kg 1 · h 1 ). After 5 days of AG, mean arterial pressure increased to 132 ± 2% control in the S rats with high Na intake and intramedullary AG compared with 121 ± 4% control ( P