Relation Between Pressure Natriuresis and Urinary Excretion of Nitrate/Nitrite in Anesthetized Dogs

作者：Dewan S. A. Majid, Murrell Godfrey, Matthew B. Grisham, Luis Gabriel Navar · 发表于：Hypertension · 年份：1995 · DOI：10.1161/01.hyp.25.4.860 · 被引用次数：51 · 研究领域：Nitric Oxide and Endothelin Effects、Anesthesia and Sedative Agents、Eicosanoids and Hypertension Pharmacology

AbstractAlterations in intrarenal nitric oxide (NO) formation during changes in renal arterial pressure (RAP) have been suggested as a mechanism mediating pressure natriuresis. To test this hypothesis further, we examined the relation between RAP and the urinary excretion rate of nitrate/nitrite (NO3−/NO2−; NO metabolites) in anesthetized sodium-replete dogs before (n=9) and during (n=6) intrarenal infusion of the NO synthesis inhibitor nitro-l-arginine (NLA; 50 μg · kg−1· min−1). Urinary NO3−/NO2−concentrations were measured with the Griess reaction and spectrophotometry methods after enzymatic reduction of NO3−to NO2−in the samples. During control conditions, there were decreases in the urinary NO3−/NO2−excretion rate in response to reductions in RAP (150 to 75 mm Hg; slope, 0.04±0.01 nmol · min−1· g−1· mm Hg−1) in association with decreases in urinary sodium excretion (UNaV). There was a positive correlation between changes in NO3−/NO2−excretion rate and changes in RAP (r=.48;P<.005) or UNaV (r=.59;P<.001). NLA infusion resulted in decreases in NO3−/NO2−excretion rate (4.8±1.4 to 1.0±0.3 nmol · min−1· g−1) in association with reductions in UNaV (4.3±0.3 to 0.7±0.2 μL · min−1· g−1), fractional excretion of sodium (2.9±0.2% to 0.5±0.1%), and renal blood flow (4.8±0.3 to 3.3±0.2 mL · min−1· g−1), without changes in glomerular filtration rate. Furthermore, there was a marked attenuation of the NO3−/NO2−and sodium excretory responses to alterations in RAP during NO synthesis in...