Central nervous system expression of the exon 9 skipping form of the glutamate transporter GLAST.

We have raised antibodies that selectively recognize an exon 9 skipping form of GLAST. We demonstrate expression of this protein in brains of rats, cats, monkeys and humans. Immunolabelling was present in scattered populations of neurons, particularly in cerebral cortex and colliculi. Neurons were often present in small clusters and exhibited a range of morphologies, from apparently normal to highly degenerate. GLAST1b was also expressed by some glial cells. Cortical neurons expressing the exon 9 skipping form of GLAST also labelled with antibodies against the C- or N-terminal regions of GLAST. We suggest that alternate splicing of GLAST by subpopulations of neurons may indicate some dysfunction in these cells, and may be an indicator of inappropriate local excitation.