The effect of deprenyl (selegiline) on intra-and extraneuronal dopamine oxidation

Abstract

— It was found that in that rat striatum DA was oxidized extrasynaptosomally to 11 % by MAO-A and to 3 % by MAO-B. The corresponding intrasynaptosomal oxidations were 84 % and 2 %, respectively. Those figures were virtually unchanged even if the rat brain MAO-B was selectively inhibited to 87 % by deprenyl. In the human brain extrasynaptosomal oxidation was 16 % and 66 %, respectively, by MAO-A and -B. Intrasynaptosomally the corresponding figures were 12 % and 6 %, respectively. Selective inhibition of human caudate MAO-B was calculated to give a total reduction of DA oxidation of 63 %. The differences between man and rat are due to the proportionately greater oxidation of DA by MAO-B in man, which is a consequence of a higher ratio of concentration of MAO-A/-B in the rat.