Alcohol inhibition of NMDA-stimulated catecholamine efflux in aging brain

The influence of aging on the ability of ethanol to inhibit N-methyl-D-aspartate-stimulated catecholamine overflow in rat brain was examined. Alcohol effects on N-methyl-D-aspartate stimulated [3H]norepinephrine or [3H]dopamine overflow from the cortex, hippocampus, and striatum of aged (24-28 months) middle aged (12-14 months), and young (3-5 months) rats were examined. N-methyl-D-aspartate (500 microM) stimulated catecholamine overflow in all brain regions, with aged rats showing declines in overflow of 33% in the hippocampus and 41% in the striatum. Alcohol (30-200 mM) produced a concentration-dependent inhibition of overflow at all ages and brain regions tested. The IC50 for alcohol inhibition of NMDA-stimulated catecholamine release was not significantly different in aged brain or across brain regions. These results indicate that alcohol's ability to inhibit NMDA-stimulated catecholamine release is not significantly altered with aging.