DENDRITIC COMPARTMENTATION OF NMDA RECEPTOR MESSENGER-RNA IN CULTUREDHIPPOCAMPAL-NEURONS

THE intracellular localization of mRNA encoding the obligatory subunit for the N-methyl-D-aspartate (NMDA) receptor complex (NMDAR1) was det ermined in cultured hippocampal neurons by in situ hybridization. From the time at which dendrites begin to develop, labelling for NMDAR1 mR NA extended beyond cell somata into incipient dendritic processes. By 10 days in culture, label was found throughout dendritic arbors in a d istribution pattern similar to that for microtublin associated protein s 2 mRNA, but contrasted sharply with that for GluR1 or beta-actin mRN As, both of which were restricted to cell somata. NMDAR1 mRNA was also expressed in astrocytes, where it was diffusely localized throughout the cytoplasm. These data suggest that transport of NMDAR1 mRNA may se rve as a mechanism to target and manipulate local concentrations of NM DA receptors.