Alterations in splanchnic blood flow following chronic ethanol exposure.

The purpose of these experiments was to determine whether or not tolerance develops to the effect of 3.0 g/kg ethanol on total and regional splanchnic blood flow in male Wistar rats. The animals were given the Lieber-DeCarli liquid diet containing ethanol for 10 days; ethanol-fed animals were withdrawn 24 hr prior to experiments. Regional blood flow and cardiac output (CO) were measured by the reference microsphere technique after an intraperitoneal injection of 3.0 g/kg of ethanol. Acute ethanol administration produced early nonsustained increases in portal vein blood flow in animals fed ethanol for 10 days and withdrawn for 24 hr and in control animals. However, after chronic exposure to ethanol, the pattern of increase in blood flow in response to ethanol in the splanchnic organs was different between the ethanol-fed and control groups. Increases in portal vein flow in control groups were due to concomitant increases in small intestinal, colonic, and cecal blood flow while the increase in the ethanol-fed group was due to a rise in small intestinal and stomach blood flow. The increase in stomach blood flow that occurred in the animals treated chronically with ethanol may be viewed as a conditioned response to ethanol, since this was not found in the control group. These results, demonstrate that the pattern of increase in blood flow in the splanchnic organs produced by an acute dose of ethanol depends on the animal's previous exposure to ethanol.