Antioxidants Condition Pleiotropic Vascular Responses to Exogenous H sub(2)O sub(2): Role of Modulation of Vascular TP Receptors and the Heme Oxygenase System

Aims: Hydrogen peroxide (H sub(2)O sub(2)), a nonradical oxidant, is employed to ascertain the role of redox mechanisms in regulation of vascular tone. Where both dilation and constriction have been reported, we examined the hypothesis that the ability of H sub(2)O sub(2) to effect vasoconstriction or dilation is conditioned by redox mechanisms and may be modulated by antioxidants. Results: Exogenous H sub(2)O sub(2) (0.1-10.0 mu M), dose-dependently reduced the internal diameter of rat renal interlobular and 3rd-order mesenteric arteries (p