Dopamine receptors in human brain: autoradiographic distribution of D1 and D2 sites in Parkinson syndrome of different etiology

Abstract

The distribution and density of dopamine D1 and D2 receptors were examined by autoradiography in postmortem brain tissue from patients with pathological diagnosis of Parkinson's disease, status lacunaris, clinical parkinsonism without neuropathological lesions and in age-matched controls. The D1 antagonist [3H]SCH 23390 and the D2 agonist [3H]CV 205-502 were used as ligands. No significant differences in the distribution or density of D1 or D2 receptors were found in Parkinson's disease in the areas examined, including the nucleus caudatus, putamen, globus pallidus and substantia nigra. In contrast, cases presenting lacunar lesions in the striatum showed marked decreases in D1 and D2 receptor densities in this region. Patients clinically diagnosed as parkinsonians but without Parkinson's disease lesions or striatal lacunar softenings showed reduced densities of D2 receptors in the nucleus caudatus and putamen, while in the substantia nigra the densities were comparable to controls. In the basal ganglia of these cases D1 receptors were slightly decreased.