Role of plasma S-nitrosothiols in regulation of blood pressure in anesthetized rabbits with special references to hypotensive effects of acetylcholine and nitrovasodilators.

The regulatory role of plasma nitrosothiols (R-SNOs) under steady-state conditions and their possible contribution to pharmacological vasodilation were systematically examined in anesthetized rabbits. Nitrosocystein (Cys-NO), S-nitrosoglutathione (G-SNO), and S-nitrosoalbumin (Alb-SNO) were determined by HPLC-Saville's method with respective sensitivities of 1, 1, and 5 nM. These R-SNOs were not detected under steady-state conditions even in the presence of N-ethylmaleimide, a thiol protective agent used to prevent transnitrosation of R-SNOs.

Quantifying nanomolar levels of nitrite in biological samples by HPLC-Griess method: special reference to arterio-venous difference in vivo.

Nitrite (NO(2)(-)) is assumed to play an important role in regulation of vascular tone as a reservoir of nitric oxide (NO). To examine its physiological contribution, however, a sensitive method is required for determination of the true level of NO(2)(-) in biological samples. To this end, practical consideration to avoid NO(2)(-) contamination through the quantification procedure is important.