AMPA-SELECTIVE GLUTAMATE-RECEPTOR SUBUNITS IN GLIAL-CELLS OF THE ADULT BOVINE WHITE-MATTER

We have investigated the presence and distribution of lpha-amino-3-hyd roxy-5-methylisoxazole-4-propionic acid (AMPA) preferring glutamate re ceptor subunits GluR1-4 in glial cells of the adult bovine corpus call osum, optic nerve and fornix. To this end, reverse transcription and p olymerase chain reaction (RT-PCR) analysis and immunohistochemical exp eriments were carried out using specific primers and antibodies for ea ch subunit. In the three areas studied, we observed that the main subu nits expressed were GluR1-3 and that they were present in the majority of astrocytes. These subunits were located throughout the cell body a nd processes of fibrous astrocytes and were particularly rich in endfe et and in the glial adventice surrounding the capillaries. In addition , we also observed by immunohistochemistry that the GluR4 subunit was present in a small subpopulation of cells which, based on their morpho logical and antigenic features, may correspond to immature cells of th e oligodendroglial lineage. These results demonstrate a differential e xpression of AMPA-selective glutamate receptor subunits with respect t o glial cell type and raise the possibility that the expression of par ticular subunits may be associated with specific functions in adult wh ite matter glial cells. (C) 1998 Elsevier Science B.V.