Alterations in [3H]spiperone binding in human caudate nucleus, substantia nigra and frontal cortex in the Shy-Drager syndrome and Parkinson's disease.
[3H]Spiperone binding was investigated in the caudate nucleus, substantia nigra (s. nigra) and frontal cortex of control subjects and of patients with Parkinson's disease and the Shy-Drager syndrome. Binding sites for [3H]spiperone were interpreted as dopamine receptors in caudate and s. nigra, and as 5-hydroxytryptamine (5-HT) receptors in frontal cortex. Scatchard analysis showed that the Bmax (maximal number of binding sites) in caudate was similar in the 3 groups, whereas in s. nigra the Bmax was reduced by approximately 60% in both Parkinsons disease and Shy-Drager syndrome. The dissociation constant (Kd) for [3H]spiperone binding in s. nigra was similar in the 3 groups. In caudate nucleus, the Kd was similar in control and Parkinson groups; however, there was a significant increase in the dissociation constant in the caudate nucleus from cases of Shy-Drager syndrome. No differences in binding characteristics were observed in the frontal cortex. These results are taken to reflect a loss of dopamine receptor sites in the s. nigra in both Parkinson's disease and Shy-Drager syndrome, and a reduced affinity of dopamine receptor sites in the caudate nucleus in Shy-Drager syndrome.
D001665:Binding Sites; D002090:Butyrophenones / Q000378:metabolism*; D002421:Caudate Nucleus / Q000378:metabolism*; D002540:Cerebral Cortex / Q000378:metabolism*; D005625:Frontal Lobe / Q000378:metabolism; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use; D009133:Muscular Atrophy / Q000188:drug therapy / Q000378:metabolism; D009468:Neuromuscular Diseases / Q000188:drug therapy / Q000378:metabolism*; D010300:Parkinson Disease / Q000188:drug therapy / Q000378:metabolism*; D011954:Receptors, Dopamine / Q000378:metabolism; D013134:Spiperone / Q000378:metabolism*; D013378:Substantia Nigra / Q000378:metabolism*; D013577:Syndrome
D002090:Butyrophenones; D011954:Receptors, Dopamine; D007980:Levodopa; D013134:Spiperone