In vitro vasorelaxant and in vivo cardiovascular effects of S-nitrosothiols: comparison to and cross tolerance with standard nitrovasodilators.

The in vitro vasorelaxant and in vivo cardiovascular effects of synthetic S-nitrosothiols (RSNOs) were compared to standard nitrovasodilators. S-Nitroso-glutathione (GSNO), S-nitroso-N-acetylcysteine (NACysNO), S-nitroso-galactopyranose (GPSNO), S-nitroso-thioglycerol (TGSNO) and S-nitroso-homocysteine (HCysNO) relaxed phenylephrine (PE) contracted rabbit aorta at 50% effective concentrations (EC 50 s) of 3-46 nM. While nitroglycerin (GTN) exhibited in vitro tolerance after preincubation, the RSNOs were considerably less cross tolerant to GTN