Studies on the Combined Effect by L-DOPA and L-alpha-hydrazinomethyldopa (MK 486) in Parkinsonism, with a Special Reference to Catecholamine Metabolism

Abstract

Following oral administration of L-DOPA alone or L-DOPA in combination with extracerebral DOPA decarboxylas inhibitor (L-alpha-hydrazinomythyldopa: MK 486), catecholamines level in plasma and cerebrospinal fluid of patients with Parkinsonism were determined by gaschromatography (ECD).After oral administration of L-DOPA in combination with MK 486, DOPA level in plasma was maintained at a higher level and for longer than after the oral administration of L-DOPA alone. Dopamine level in plasma was markedly lower than with L-DOPA aloneDopamine level in cerebrospinal fluid after oral administration of L-DOPA in combination with MK 486 was maintained at a higher level than after the oral administration of L-DOPA alone.Thus, judging from DOPA and dopamine levels in plasma, a combination-ratio of L-DOPA and MK 486 of 10 to 1 was found to be desirable.