MODULATION OF THE STRESS-RESPONSE BY ETHANOL IN THE RAT FRONTAL-CORTEX

Microdialysis was used to characterize the effects of two doses of eth anol, stress, and their interaction on the dopaminergic system. Saline -treated animals showed no changes in levels of dopamine (DA) or dihyd roxyphenylacetic acid (DOPAC). Neither a 0.5- nor a 2-g/kg IP injectio n of ethanol had an effect on DA or DOPAC in resting animals. Immobili zation caused marked increases in DA levels and smaller increases in D OPAC. Pretreatment with 0.5 g/kg ethanol did not reduce the stress-ind uced increase in DA or DOPAC. However, pretreatment with 2 g/kg ethano l strongly reduced and antagonized the stress-induced increases in DA and potentiated the stress-induced increase in extracellular DOPAC. Ou r data show that ethanol can have different, dose-dependent effects in resting vs. stressed animals, that it has different effects on DA and DOPAC, and that the high dose antagonized stress-induced increases in DA. The latter adds biochemical evidence to the tension-reduction hyp othesis of ethanol by perhaps implicating a reduction in the DA stress response by ethanol as a contributing factor in the development of al coholism.