Platelet dopamine uptake in Huntington's chorea and Gilles de la Tourette's syndrome: effect of haloperidol.

Uptake of 14C-dopamine by human platelets has been studied in two diseases, namely Gilles de la Tourette's syndrome and Huntington's chroea, in which abnormal metabolism of dopamine has been implicated. Platelets from untreated Huntington's chorea patients showed a small increase in Km and Vmax.; platelets from patients in all other groups showed an uptake identical with the controls. Haloperidol (10(-5)M) was also shown to be a strong non-competitive inhibitor of 14C-DA uptake by platelets. This property is probably unrelated to the drugs' action in ameliorating the symptoms of Huntington's chorea which is likely related to the increase in cholinergic neuronal activity produced by neuroleptic blockade of dopamine receptors.