DIFFERENTIAL SENSITIVITY OF NMDA RECEPTOR-MEDIATED SYNAPTIC POTENTIALS TO ETHANOL IN IMMATURE VERSUS MATURE HIPPOCAMPUS

Pharmacologically isolated, NMDA receptor-mediated population EPSPs (p EPSPs) were evoked from area CA1 of hippocampal slices using electrica l stimulation of the Schaffer collateral/commissural fiber pathway, Sl ices were prepared from rats aged 20-25 or 80-100 days, The inhibitory effects of a range of ethanol concentrations were assessed. While eth anol antagonized NMDA-mediated pEPSPs in slices from both age groups, it was significantly more potent against pEPSPs from immature versus m ature hippocampi, In slices from mature animals, significant and consi stent reduction of pEPSPs was observed only with the highest ethanol c oncentration (100 mM), whereas 10, 30, or 100 mM significantly reduced the amplitude of pEPSPs in slices from immature animals. These result s indicate that NMDA-mediated synaptic activity in the hippocampus is more sensitive to the effects of ethanol in immature versus mature ani mals.