IMMUNOCYTOCHEMICAL LOCALIZATION OF AMPA RECEPTORS IN THE RAT INFERIORCOLLICULUS

Immunocytochemistry was used to study the distribution of lpha-amino-3 -hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor acid (AMPA ) receptor subtypes in the inferior colliculus (IC) of genetically epi lepsy-prone rats (GEPR-9s) and normal Sprague-Dawley (SD) rats. The an alysis was conducted using 3 antibodies specific for glutamate recepto r subtypes, GluR 1, GluR 2/3, and GluR 4. Light microscopy showed that immunostaining of the IC was most dense with the GluR 2/3 antibody fo r both strains of animals. The amount of GluR 2/3 immunolabeling was s imilar for sound-stimulated GEPR-9s, seizure-naive GEPR-9s. and SD rat s. The electron microscopy of GluR 2/3 in the IC revealed immunoreacti on products associated with the postsynaptic densities of asymmetric s ynapses. The thin sections had comparable amounts of reaction product in dendrites or dendritic spines for both strains. Since the distribut ion and quantity of AMPA receptors in the IC of GEPR-9s and SD rats ar e similar, our results indicate that altered AMPA receptors are probab ly not the primary cause of seizure initiation in GEPR-9s. (C) 1997 El sevier Science B.V.