EFFECTS OF ETHANOLON NMDA-MEDIATED INTRACELLULAR FREE <TEX>$Ca^{2+}$</TEX> CONCENTRATION IN DISSOCIATED BRAIN CELLS

Using fluorescent probe fura-2 acetoxymethyl ester, we studied effects of N-Methyl-D-aspartate (NMDA) on free intracellular <TEX>$Ca^{2+}$</TEX> concentration ([<TEX>$Ca^{2+}$</TEX>]<TEX>$_{i}$</TEX>) and interaction of ethanol with NMDA-mediated response in freshly dissociated brain cells from newborn rats. Twenty five micromolar NMDA significantly increased (<TEX>$Ca^{2+}$</TEX>), and this increasing effect could be prevented or reversed by the NMDA antagonists <TEX>$Mg^{2}$</TEX>(1.0 mM) and 2-amino-5-phosphonovalerate (AP5, 100 <TEX>${mu}$</TEX>M). Ethanol at concentrations from 2.5 to 100 mM inhibited NMDA-mediated calcium current in a concentration-dependent manner. Maximal inhibition of NMDA-mediated calcium current by ethanol was 82% at 50 mM. The ethanol inhibition at 100 mM was not significantly different from the inhibition at 50 mM.