(+/-)-Alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid and kainate receptor subunit expression in mouse versus rat spinal cord white matter: similarities in astrocytes but differences in oligodendrocytes.

Our recent study on ionotropic (+/-)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)/kainate (KA) type glutamate receptors in mouse spinal cord revealed differences compared with reports on other species. Inconsistencies in such findings may reflect real inter-species variability or differences in technique. To date, no comprehensive study has directly addressed this issue. Thus, we compared, side-by-side, AMPA/KA receptor expression in mouse and rat spinal cord white matter. Tissue from both species underwent identical processing, using the same reagents, immunofluorescence protocol, and confocal microscopy. Both mouse and rat white matter astrocytes displayed similar AMPA/KA subunit profiles (both species, GluR2/3 and GluR6/7). However, substantial inter-species differences were found for oligodendrocytes (KA2 in mouse; GluR4 and GluR2/3 in rat). Knowledge of such differences can aid in understanding the effects of variably selective AMPA/KA antagonists on glutamate excitotoxicity in white matter.