Heterogeneous dopamine receptor changes in early and late Huntington's disease.

Quantitative receptor autoradiography was used to study dopamine (DA) receptors in dorsal striatum and its projection regions in brains from individuals dying with Huntington's disease (HD) and controls. Heterogeneous loss of both D1 and D2 receptors was present in the striatum of early and late stage HD brains. The degree of receptor loss was greater for the D1 receptor than for the D2 receptor in early stage HD. The pattern of receptor loss did not correspond to heterogeneities identified with acetylcholinesterase staining. Progressive loss of D1 receptors in the internal globus pallidus and substantia nigra pars reticulata and D2 receptors in the external globus pallidus corresponded to advancing pathologic grade.