5-HT1B RECEPTOR-BINDING IN DEGENERATIVE MOVEMENT-DISORDERS

Using [H-3]sumatriptan as a radioligand, 5-hydroxytryptamine (5-HT)(1B ) receptors were examined in posterior striatum and midbrain post-mort em tissue sections of 12 patients who had died from representative deg enerative movement disorders as compared to nine controls. In the cont rol human basal ganglia, the highest densities of [H-3]sumatriptan bin ding were observed in the globus pallidus and substantia nigra. No sig nificant change in the density of [H-3]sumatriptan binding sites was f ound in the striatum and substantia nigra of the six Parkinson's disea se brains. In the two brains from patients with progressive supranucle ar palsy an increase was found in the densities of [H-3]sumatriptan bi nding sites, most marked in the substantia nigra. In contrast, [H-3]su matriptan labelling was almost absent in the striatonigral degeneratio n brain and was markedly reduced in the three Huntington's disease bra ins. This study indicates that the status of 5-HT1B receptors is diffe rent in each degenerative movement disorder and suggests that human 5- HT1B receptors are located somatodendritically on GABAergic and peptid ergic caudate-putamen neurons which project to the substantia nigra an d globus pallidus, where these receptors are presynaptic. (C) 1998 Els evier Science B.V.