摘要：Despite of the importance of plasma NO2− as an index of endothelial nitric oxide (NO) formation and a substrate for NO production, only a limited kinetic knowledge is available in vivo . To address this issue, we intravenously injected NaNO2 into anesthetized rabbits and quantified changes in arterial and venous plasma NO2− levels. Plasma NO2− levels in arterial blood (956±220 n M ) were slightly, but significantly, higher than those in venous blood (889±214 n M ) under control conditions. Although similar half-lives of the NO2− were observed in arterial and venous plasma, significant arteriovenous differences were observed in the volume of distribution of the central compartment (0.158±0.007 l/kg in arterial blood and 0.295±0.015 l/kg in venous blood) and the peripheral compartment (0.259±0.035 l/kg in arterial blood and 0.135±0.034 l/kg in venous blood). When NOR1 (authentic NO) was injected, increases in NO2− levels were greater in arterial plasma, and decreases in blood pressure significantly correlated with arterial NO2− levels only ( r =0.90, p <0.01). These results indicate that changes in NO2− are larger and more easily detectable as an index of NO formation in arterial plasma.
