[Abnormal movements of patients with Parkinsonism treated with L-dopa and anomalies of dopamine metabolism].

The authors describe the results of biochemical analysis carried out on 28 patients with Parkinson's disease who had been treated by L-dopa. Twenty of them showed either no abnormal movements at all or very few, eight others had considerable dyskinesia. Biochemical analysis of the urinary degradation products of L-Dopa revealed the existence of a swing in the degradation of dopamine towards 4-O-methylate derivatives in dyskinetic patients (significant difference at .01). The results confirm those obtained in their initial analysis carried out in 1973. The authors express the view that abnormal movements while under L-Dopa treatment are dependent on two factors: one, the hypersensitivity of dopaminergic reception, the other, the greater or lesser preponderance of the COMT isozyme giving rise to 4-O-methylates;