Vasorelaxation by L-arginine after L-NAME administration in rabbits consuming moderate amounts of red wine

Red wine and its constituents have been shown to stimulate endothelium-de-pendent and nitric oxide (NO)-mediated vasorelaxation in vitro in the isolated and precon-tracted aortic rings. The present study investigated if this occurred in vivo in rabbits, which chronically consumed a moderate amount of red wine. Nωnitro-L-arginine-methyl ester (L-NAME) and L-arginine was infused into the rabbits that consumed red wine (7mL/kg/d), ethanol (99.5%, 0.8mL/kg/d), or water alone for 4 weeks, and the vaso-constrictive/-dila-tive response was studied in the renal artery. Following treatment with L-NAME (30mg/kg), the renal blood flow rate decreased and renal vascular resistance increased. Only in the ani-mals consuming red wine did a subsequent administration of L-arginine (300mg/kg) in-crease the renal blood flow rate and decrease the renal vascular resistance. The effects were associated with the increase in the renal NO metabolite (nitrite/nitrate, NO2-/NO3-) pro-duction rate. From the present in vivo model, it is suggested that vasorelaxation by L-argi-nine is through the NO pathway and that the effects observed in the animals consuming the red wine cannot be attributed to alcohol alone.