Alterations in splanchnic blood flow after low and high doses of ethanol

The purpose of this investigation was to determine the effect of various acute doses of ethanol (1.0, 3.0, 4.0 g/kg) on the distribution of cardiac output (%CO) and blood flow to the splanchnic vascular bed in conscious male Wistar rats. Regional blood flow and cardiac output (CO) were measured by the reference microsphere technique. Mean arterial pressure and CO were significantly reduced 60 min after 3.0 g/kg and 4.0 g/kg of ethanol, while no changes occurred over time in total peripheral vascular resistance or heart rate. Acute ethanol administration produced an early non-sustained increase in portal vein blood flow, that was most pronounced after a low dose of ethanol, and was attenuated after the 3.0 g/kg and 4.0 g/kg doses of ethanol. The early increase in portal vein blood flow produced a corresponding increase in total liver blood flow. Additionally, we found increases in hepatic arterial blood flow after the higher doses. The combined increase in portal vein and hepatic arterial supply to the liver may serve to increase oxygen delivery, more than the singular increase in portal vein blood flow. This early increase in total liver blood flow after high doses of ethanol may be important for protecting hepatocyte function in the presence of high blood ethanol levels.