Expression of glutamate transporters in cultured glial cells.

Expression of mRNAs for glutamate transporter (GLT-1) and glutamate aspartate transporter (GLAST) was investigated in three different types of purified glial cells by the reverse transcriptase-polymerase chain reaction (RT-PCR). Cultured astrocytes, oligodendrocytes, and microglia expressed mRNAs for GLAST and GLT-1; mRNA for GLAST was expressed more prominently than that for GLT-1 in astrocytes. Oligodendrocytes and microglia expressed mRNAs for both GLT-1 and GLAST equally, but the expression in microglia was not prominent, suggesting glutamate uptake is not essential in microglia. In astrocytes cultured from different brain regions, GLAST mRNA was equally expressed. GLT-1 mRNA was also detected in these astrocytes, but the expression level was lower than that of GLAST.