[The effect of withdrawal from L-DOPA compounds on pathochemical changes of motor structures of the brain caused by them].

Activities of enzymes of protein metabolism (aminopeptidase, acid phosphatase), of neurotransmitters (monoamine oxidase, acetylcholinesterase) and oxidative metabolism (glutamate- and glucose-6-phosphate dehydrogenases) were studied by quantitative cytochemical procedures in brain motor structures (sensomotor cortex, caudate nucleus) as well as in brain tissues not related directly to locomotory functions (n. accumbens, hippocampus) of rats exhibiting high and low locomotory activities after repeated L-DOPA administration within 14 days as well as within 14 days after drug discontinuation. That of L-dopa (madopare) caused alterations in the enzymatic activity in the brain motor structures of rats, mainly, with a high locomotory activity. It may be suggested that madopare withdrawal-induced decreases in MAO activity might be, to a certain extent, a cause of dyskinesias occurring after discontinuation of L-DOPA drugs.