COEXPRESSION OF RECEPTOR MESSENGER-RNA AND PROTEIN - STRIATAL DOPAMINE AND EXCITATORY AMINO-ACID SUBTYPES

Dopamine (DA) is known to modulate the post-synaptic response of the e xcitatory amino acid (EAA) neurotransmitters in the striatum. Thus the intrinsic neurons in this nucleus are potential sites of cross-intera ction between these two systems. The recent isolation of 5 different D A receptor subtypes and more than 20 EAA subunits argues for a complic ated functional role for the protein products encoded by these transcr ipts. The simultaneous detection of cellular mRNA distributions and tr anslated protein products was an initial step to determine differences in post-translational expression at the cellular level of resolution for two of these receptors. The cloned D-2 DA receptor subtype and the ionotropic GluR, EAA receptor subunit were examined by fluorescence i n situ transcription (FIST) following hybridization of specific cDNA p rimers, complementary to the mRNA transcripts encoding these receptors . Nascent extension of the annealed primer using reverse transcriptase was detected after incorporation of fluorescently labeled dUTP. Prote in products were visualized by standard immunofluorescence after incub ation with anti-peptide antisera that were selective for each receptor protein. The experimental data corroborate previous work describing t he regional expression of ligand binding and in situ hybridization det ected with radiolabeled probes for the DA and EAA receptor systems in the striatum. The dual fluorescence method can be completed within 2 d ays and may be adapted to cellular localization of many novel mRNA/pro tein combinations to examine post-translational processing within thin tissue slices.