Coexpression of striatal dopamine receptor subtypes and excitatory amino acid subunits

✍ Scribed by Marjorie A. Ariano; Eric R. Larson; Kurt L. Noblett; David R. Sibley; Michael S. Levine

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 654 KB
• Volume: 26
• Category: Article
• ISSN: 0887-4476
• DOI: 10.1002/(sici)1098-2396(199708)26:4<400::aid-syn8>3.0.co;2-a

✦ Synopsis

The striatal cellular coexpression patterns for the D 1A and D 2 dopamine (DA) receptor subtypes and the ionotropic excitatory amino acid (EAA) subunits of the N-methyl-D-aspartate (NMDA-R 1 ) and the a-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) (GluR 1 and GluR 2/3 ) receptor subunits were examined morphologically. Their coincidence was assessed by visualization of mRNA transcripts, localization of encoded receptor proteins, and binding analysis using concurrently paired methods of fluorescence detection. The findings indicated that 1) mRNA transcripts for both receptor systems were detected in the medium-sized neuron population, and the distribution of receptor message closely reflected protein and binding patterns, with the exception of the GluR 1 subunit; 2) both DA receptor mRNA transcripts were coexpressed with each ionotropic EAA receptor subunit examined and with each other, and NMDA and AMPA receptor subunits also showed coincident expression; 3) D 1A DA receptor protein was detected in neurons which coexpressed EAA subunit proteins; and 4) GluR 2/3 and NMDA-R 1 subunit proteins were coexpressed in medium-sized neurons which also demonstrated D 2 DA receptor binding sites. These findings suggest morphological receptor ''promiscuity'' since the coexpression patterns between DA and EAA receptors were found in all permutations. The results provide a spatial framework for physiological findings describing functional interactions between the two DA receptor types and between specific DA and EAA receptors in the striatum.