[Results of determination of plasma methoxydopa in parkinsonian patients with or without dyskinesia induced by L-Dopa].

Horary plasmatic dosages of Dopa and metabolites in 30 treated parkinsonian patients have shown that, within the group of patients treated with L-Dopa combined with an extracerebral decarboxylase inhibitor, highly significant by increased plasmatic O-methyl-dopa levels can be found in patients with dyskinesias compared with those without dyskinesias. On the contrary, in these two subgroups of patients, plasmatic Dopa levels are not significantly different. By comparing some favoured Dopa and O-methyl-dopa levels between these two subgroups of patients, it seems more likely, that the elevated plasmatic O-methyl-dopa levels are due to an progressive accumulation on of its compound than to an excessive formation from Dopa.