Autoradiographic localization of D1 and D2 dopamine receptors in the human brain.

The distribution of dopamine D1 and D2 receptors in several human brain regions was investigated using autoradiography with the radioligands [3H]SCH 23390 and [3H]spiroperidol. The highest densities of both dopamine receptor types are seen in the nucleus caudatus, putamen and nucleus accumbens. Whereas the density of the D2 receptors is similar in the two segments of the globus pallidus, the pars medialis of the globus pallidus contains a three-fold higher concentration of D1 receptors than the pars lateralis. D1 and D2 receptors are present in the amygdala and substantia nigra. Both receptor types are absent in the cerebellum. The thalamus contains low densities of D1 receptors but no D2 receptors. Only D2 receptors are seen in the anterior lobe of the pituitary gland. The whole cerebral cortex is rich in D1 receptors, while D2 receptors, in low concentrations, are confined to the entorhinal area and cingulate cortex.