Striatal excitatory amino acid receptor subunit expression in the D1A-dopamine receptor-deficient mouse

The influence of dopamine receptor deletion on the expression and distribution of striatal excitatory amino acid (EAA) receptor subunits comprising the N-methyl-D-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) subtypes were examined in the D1A dopamine (DA) receptor-deficient mouse. EAA receptor subunit immunofluorescent staining was altered by the DA receptor genetic mutation. The NMDA-R1 subunit was used as a marker for NMDA-type receptors. The number of striatal neurons expressing this subunit decreased and there was a modest attenuation in the neuropil staining in the mutants in contrast to littermate controls. The R1 subunit for the glutamate receptor (GluR1) was used as an indicator of the AMPA receptor subtype. Immunostaining for this subunit also showed changes induced by deletion of the DA receptor subtype. In contrast to the NMDA-R1 subunit, neuropil staining for the GluR1 subunit was elevated in the mutant in comparison to littermate controls, such that the immunofluorescent reaction obscured detection of the subunit protein in striatal interneurons. The results are discussed in relation to the potential impact on functional interactions between the EAA and DA systems in the striatum.