Substrate-selective inhibition of monoamine oxidase by some cyclopropylamino substituted oxadiazoles

Abstract

1. Inhibition of rat monoamine oxidase by 5-phenyl-3-( N-cyclopropyl) ethylamine-1,2,4-oxadiazole (PCO) has been studied in vitro and in vivo. The compound is an irreversible inhibitor showing selectivity for the serotonin oxidising site (A-site) of the enzyme. 2. Substitution in the 5-phenyl ring of PCO gives compounds which may also be selective for the A-site such as the 2-chlorophenyl compound, may show no selectivity or may, like the 3-nitrophenyl compound, be selective for the B-site of the enzyme. 3. The selectivity found when these inhibitors react with monoamine oxidase in vitro is also apparent when the enzyme from rats which have received single doses of the compounds is studied, but is less clearcut after repeated administration.