DEVELOPMENTAL-CHANGES IN SUBCELLULAR AMPA GLUR RECEPTOR POPULATIONS IN RAT FOREBRAIN/

Forebrains from rats of postnatal days (PND) 2, 7, 14, 21, and 30-40 w ere subjected to subcellular fractionation and samples from crude mito chondrial (P2, which contain synaptic plasma membranes) and microsomal (P3) fractions were used for SDS-PAGE and Western blotting with antib odies against GluR1, and GluR2/3 subunits of AMPA/GluR receptors. GluR immunoreactivity in P2 fractions increased gradually from PND 2 to PN D 30. in contrast, GluR immunoreactivity in P3 fractions increased sha rply at early postnatal ages, and was higher than in adults as early a s at PND 7. Data were compared to postnatal changes in H-3-AMPA bindin g reported in various studies. Significant correlations were observed between changes in GluR immunoreactivity in P3 fractions and changes i n high-affinity binding on one hand and between changes in GluR immuno reactivity in P2 fractions, and changes in low affinity binding. These data further establish that glutamate receptors present in different subcellular compartments represent different maturational states of th e receptors, and suggest that changes in GluR populations could partic ipate in mechanisms of synaptic plasticity. (C) 1998 Elsevier Science B.V.