D2 dopamine receptor distribution in the rodent CNS using anti-peptide antisera.

D2 dopamine receptors were identified immunohistochemically in rodent tissues using anti-peptide antisera to distinguish regional and cellular staining patterns. These subtype selective polyclonal antibodies were directed against both extracellular and intracellular regions of the native protein and showed that the D2 dopamine receptors are widely distributed within the nervous system. The highest expression of D2-like dopamine receptor immunoreactivity was visualized in the forebrain and components of the basal ganglia, supportive of previous investigations of the D2 dopamine receptor distribution using in vitro autoradiographic ligand binding or in situ hybridization for its messenger RNA. The anti-peptide antisera could detect the dopamine receptor in both perfusion-fixed and fresh-frozen tissue preparations. The reactive cells and their processes could be distinguished using experimental incubations from 1:8,000 (in immunofluorescence processing) to 1:80,000 (in immunoperoxidase processing) in the most reactive nervous system region, the neostriatum. The antisera are selectively directed against extracellular or intracellular epitopes in both the long and short isoforms of the D2 dopamine receptor, and should prove useful in subsequent studies of the subcellular distribution of this receptor in particular, and the dopamine system in general.