AUTORADIOGRAPHIC DISTRIBUTION OF D-3-TYPE DOPAMINE-RECEPTORS IN HUMAN BRAIN USING [H-3] 7-HYDROXY-N,N-DI-N-PROPYL-2-AMINOTETRALIN

The regional distribution of D-3 dopamine receptors was studied in human brain by quantitative autoradiography with [H-3]7-hydroxy-N,N-di-n-propyl-2-aminotetralin ([H-3]7-OH-DPAT). The highest densities were found in the ventral striatum/nucleus accumbens, followed by the remainder of the neostriatum, cerebral cortex, and cerebellar cortex. Moderate amounts were found in the substantia nigra. Low densities of D-3 dopamine receptors were visualized in pituitary gland (posterior lobe > anterior lobe), amygdala, and hippocampus. The globus pallidus and thalamus contained lower densities. The distribution pattern is much more widespread as detected by in situ hybridisation histochemistry for D-3 mRNA in human and in rat brain. Our data confirm a predilection of D-3 receptors in brain areas involved in cognitive and emotional functions. The presence of D-3 receptors in non-limbic parts of the neostriatum and substantia nigra suggests that they also play a role in the dopaminergic control of motor processes. Its precise function in cerebellum and pituitary gland is at present uncertain.