Free Radical Production during Ethanol Intoxication, Dependence, and Withdrawal

Indices of free radical production and cell damage were examined in male Sprague-Dawley rats chronically exposed to either ethanol (ETOH) or water vapor. In experiment 1, rats experienced either 1 or 11 cycles of ETOH exposure and withdrawal. Brain tissue was harvested 12 hr after ETOH exposure, and 1 hr after being injected with sodium salicylate as a scavenger. Brain tissue was analyzed for the formation of salicylate hydroxylation products as a measure of OH production during withdrawal. Significant group differences for OH production were demonstrated for 2,3- and 2,5-dihydroxybenzoic acid in the single cycle ETOH exposed rats compared with their water cohorts. A significant between group difference for 2,5-dihydroxybenzoic acid, only, was demonstrated for the multiple cycles of ETOH exposure. Spontaneous seizures were shown to correlate with increased production of OH in ETOH exposed rats. In experiment 2, brain tissue was harvested from different groups of rats after removal from the chambers, at 0, 2, 12, 24, 36, and 48 hr after a single exposure cycle. Tissue was analyzed for (1) salicylate hydroxylation (as above), (2) glutamine synthetase activity, (3) whole brain glutamate concentration, and (4) oxidized protein. A multiple regression analysis was conducted on the five dependent variables and found they could be predicted by specific behavioral and neurological ratings. These data suggest that cell damage during withdrawal may have multiple time-dependent components.