NITRIC-OXIDE MEDIATES THE BLOOD-FLOW RESPONSE TO INTRAVENOUS ADENOSINE IN THE RABBIT

The objective of this study was to determine if nitric oxide mediates the effects of exogenously administered adenosine on peripheral blood flow. An intravenous infusion of adenosine (1.0 mu mol/kg/min) into ma le New Zealand white rabbits caused an increase in blood flow, measure d using radiolabeled microspheres, throughout the gastrointestinal tra ct, as well as in the heart and kidneys. Prior administration of nitro -L-arginine methyl ester (L-NAME) 10 mg/kg i.v. completely blocked the hyperemic effect of adenosine on all organs studied. Administration o f L-arginine (300 mg/kg bolus and 50 mg/kg/min infusion) together with L-NAME restored the hyperemic effect of adenosine. This phenomenon wa s specified to the L-arginine/nitric oxide pathway in that a similar p resser response induced by phenylephrine (1.5 mu g/kg/min) did not blo ck the effects of adenosine. We conclude that the peripheral vasodilat or response to intravenously administered adenosine in the rabbit is m ediated by nitric oxide. (C) 1994 Wiley-Liss, Inc.