ACUTE ETHANOL EFFECTS ON FOCAL CEREBRAL-ISCHEMIA IN FASTED RATS

The effects of acute ethanol intoxication were investigated in a rat m odel of unilateral middle cerebral artery occlusion. Groups of 5 to 8 male Sprague-Dawley rats were subjected to 4 hr of left middle cerebra l artery occlusion. All groups were deprived of food overnight and wer e pretreated intraperitoneally with 5% dextrose solution (10 ml/kg), 2 0% ethyl alcohol in 5% dextrose solution (2 g/kg), or 30% ethyl alcoho l in a 5% dextrose solution (3 g/kg) 1 hr before middle cerebral arter y occlusion. Regional cerebral blood flow during ipsilateral occlusion was similar to 9.1 to 10% of baseline in all groups. The mean % brain water content in control, 2 g/kg ethanol-treated groups, and 3 g/kg e thanol-treated groups were: in the ischemic core-81.6, 81.2, and 82.4; intermediate zone-80.5, 80.6, and 81.7; and outer zone-79.7, 79.7, an d 80.8, respectively. Brain Na+ and K+ content in the three groups was related to water content, but much greater with ethanol pretreatment. The water content of the intermediate zones in the 3 g/kg ethanol-tre ated animals was significantly greater than in the control (p < 0.01 a nd 0.001) and the 2 g/kg ethanol-treated groups. One-way analysis of v ariance indicated a significant dose-effect relationship in which the lower dose of ethanol tended to reduce ischemic core water content, an d the larger dose increased ischemic core water, compared with the con trol. None of the overnight fasted groups had any significant hypergly cemia. The group given 3 g/kg ip ethanol 1 hr before had exacerbated e dema formation with a mean whole blood level of ethanol of similar to 230 mg/dl. The neurotoxic effects of high concentrations of ethanol we re unrelated to any change in plasma glucose concentrations.