Chronic ethanol-mediated up-regulation of the N-methyl-D-aspartate receptor polypeptide subunits in mouse cortical neurons in culture

The goal of this study was to determine whether chronic ethanol-mediated up-regulation of the N-methyl-D-aspartate receptors (NMDAR) was associated with an augmentation of the NMDAR polypeptide subunits in the mammalian cortical neurons. The results show that chronic ethanol treatment produced an increase in the R1 and R2B polypeptide subunits. The R2A subunit was not expressed in these neurons. Chronic NMDAR antagonist ((+)-3-2-(carboxypiperazin-4-yl)propyl-1-phosphonic acid (CPP)) treatment also increased the R1 and R2B polypeptide subunits. A similar increase was observed when ethanol and CPP were used in combination. Binding studies using [H-3]MK-801 ((+)-5-methyl-10,11-dihydro -5H-dibenzo[a,d]cyclophenptan-5,10-imine maleate), a noncompetitive NMDAR antagonist, confirmed that concomitant exposure of ethanol and CPP up-regulated the NMDAR. Our results demonstrate for the first time that chronic ethanol treatment increased the NMDA receptor polypeptide subunit synthesis and that it was associated with an increase in [H-3]MK-801 binding sites.