Nitric oxide and nitric oxide synthase in the kidney: Potential roles in normal penal function and in renal dysfunction

A detailed overview of nitric oxide and nitric oxide synthases in the kidney is presented. Physiologically, constitutive and inducible nitric oxide synthases have been detected in basically all vascular segments of the kidney, including all large vessels and arterioles that are primarily involved in the regulation of renal hemodynamics. It was observed that nitric oxide increases renal blood flow, decreases renal vascular resistance, and exerts variable effects on glomerular filtration rate depending on the experimental conditions. In addition, macula densa generated nitric oxide appears to mediate tubuloglomerular feedback. Constitutive and inducible nitric oxide synthases have also been delineated in most renal tubular segments. The inner medullary collecting duct was shown to contain the highest amount of constitutive nitric oxide synthase as compared to other nephron segments. It appears that nitric oxide may directly enhance tubular reabsorption in the collecting duct and the proximal tubule. Pressur...