Acute Ethanol Intake Induces NAD(P)H Oxidase Activation and Rhoa Translocation in Resistance Arteries

BACKGROUND: The mechanism underlying the vascular dysfunction induced by ethanol is not totally understood. Identification of biochemical/molecular mechanisms that could explain such effects is warranted. OBJECTIVE: To investigate whether acute ethanol intake activates the vascular RhoA/Rho kinase pathway in resistance arteries and the role of NAD(P)H oxidase-derived reactive oxygen species (ROS) on such response. We also evaluated the requirement of p47phox translocation for ethanol-induced NAD(P)H oxidase activation. METHODS: Male Wistar rats were orally treated with ethanol (1g/kg, p.o. gavage) or water (control). Some rats were treated with vitamin C (250 mg/kg, p.o. gavage, 5 days) before administration of water or ethanol. The mesenteric arterial bed (MAB) was collected 30 min after ethanol administration. RESULTS: Vitamin C prevented ethanol-induced increase in superoxide anion (O(2)(-)) generation and lipoperoxidation in the MAB. Catalase and superoxide dismutase activities and the reduced glutathione, nitrate and hydrogen peroxide (H(2)O(2)) levels were not affected by ethanol. Vitamin C and 4-methylpyrazole prevented the increase on O(2)(-) generation induced by ethanol in cultured MAB vascular smooth muscle cells. Ethanol had no effect on phosphorylation levels of protein kinase B (Akt) and eNOS (Ser(1177) or Thr(495) residues) or MAB vascular reactivity. Vitamin C prevented ethanol-induced increase in the membrane: cytosol fraction ratio of p47phox and RhoA expression in the rat MAB. CONCLUSION: Acute ethanol intake induces activation of the RhoA/Rho kinase pathway by a mechanism that involves ROS generation. In resistance arteries, ethanol activates NAD(P)H oxidase by inducing p47phox translocation by a redox-sensitive mechanism.