Abstract: Chronic administration of a low dose of reversible monoamine oxidase (MAO) B inhibitors isatin or himantane (20 mg/kg) to mice during 21 day did not influence the enzyme activity assayed in isolated brain mitochondria. However in vivo sensitivity of brain MAO B to irreversible mechanism-based inhibitor deprenyl injected to animals right after the last administration of the reversible inhibitor sharply decreased. This suggests accumulation of these compounds (or their metabolites?) in the brain accompanied by increased protection of active site of MAO B against specific irreversible inhibitor, deprenyl. In vitro inhibition of MAO B activity in mitochondria isolated from brain of mice treated with isatin or himantane was somewhat higher than in control mitochondria. The latter suggests that long term treatment of animals with reversible easily dissociating inhibitors may influence regulatory properties of MAO B.
Reference: Valdman E.A., Kapitsa I.G., Nerobkova L.N., Axenova L.N., Buneeva O.A., Medvedev A.E., The effect of long-term administraion of isatin and hemantan to mice on sensitivity of brain monoamine oxidase B to inhibition by deprenyl in vivo and in vitro, Biomeditsinskaya khimiya, 2004, vol:
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