EXPOSURE OF NEURONAL CULTURES TO K+ DEPOLARIZATION OR TO N-METHYL-D-ASPARTATE INCREASES THE TRANSCRIPTION OF GENES ENCODING THE ALPHA-1 AND ALPHA-5 GABA(A) RECEPTOR SUBUNITS

The transcription rates of the alpha 1, alpha 5, and alpha 6 gamma-aminobutyric acid(A) receptor subunit genes were analyzed in cultures maintained in low KCl (12.5 mM), in low KCl treated with NMDA (10 mu M), and in high KCl (25 mM). alpha 1 and alpha 5 transcription rates were significantly increased in response to NMDA or high KCl treatment, while alpha 6 and cyclophilin transcription rates were not changed by either condition. These data suggest that following NMDA or high KCl treatment of granule cells, changes in alpha 1 and alpha 5 mRNA content are a consequence of a specific transcriptional rate increase of the corresponding subunit genes.