Pallidal GABA and chorea in Huntington's disease.

Neurochemical correlates of chorea in Huntington's disease were studied using striatal and pallidal tissue taken post mortem from patients with mild and severe chorea. While GABA was decreased in all these areas in Huntington's disease, patients with mild chorea had significantly less GABA in the medial pallidum than did those with severe chorea. There was no relationship between the degree of chorea and concentrations of dopamine or its metabolite. Thus the chorea of Huntington's disease may relate to the balance of residual GABAergic innervation between specific areas of the basal ganglia, consistent with primate models of dyskinesias.