抄録
An assay of platelet monoamine oxidase type-B (MAO-B) activity has been explored in the search for a reliable method of discriminating selegiline (SG) use from methamphetamine (MA) abuse. MAO-B activity was measured by fluorimetry of 4-hydroxyquinoline (4HOQ) produced by oxidative deamination of kynuramine, the substrate for MAO-B. MA and most of its related compounds including its precursors produced no platelet MAO-B inhibition in vitro even at their lethal levels, though SG, its specific metabolites selegiline N-oxide (SGO) and N-desmethylselegiline (DM-SG), as well as its enantiomer d-deprenyl exhibited high platelet MAO-B inhibitory potency. In vivo, remarkable inhibition of MAO-B occurred even within an hour after drug administration, and the inhibition apparently lasted approximately 6-8 days after both 2.5 and 7.5 mg oral doses of SG hydrochloride. The present study suggests that the decrease of platelet MAO-B activity would be a significant marker to discriminate SG use from MA abuse, even a week after drug use.
