title: Differential postnatal development of monoamine oxidases A and B in the blood-brain barrier of the rat.
abstract: We studied the monoamine metabolizing mitochondrial enzyme, monoamine oxidase (MAO), in cerebral microvessels obtained from postnatally developing rats by measuring the specific binding of [3H]pargyline, an irreversible inhibitor of MAO, and the rate of oxidation of three known MAO substrates: benzylamine, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, and tryptamine. MAO activity increased postnatally, with the greatest increase occurring in the second week and reaching a peak at 3 weeks of age. A concomitant increase in MAO of the cerebral cortex also occurred, but was several-fold less than that of cerebral microvessels. Using clorgyline and deprenyl, relatively specific inhibitors of MAO-A and MAO-B, we showed that cerebral microvessels contain both forms of MAO at all ages, but there was a major preponderance in the postnatal development of MAO-B. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analyses of rat microvessels after [3H]pargyline binding also showed two distinct bands of radioactivity at all ages. These two bands corresponded to molecular weights of approximately 65,000 for MAO-A and approximately 60,000 for MAO-B. SDS-PAGE results of brain microvessels obtained from 1-, 14-, and 42-day-old rats confirm the differential postnatal development of MAO-B in rat brain microvessels.
mesh_terms: D000375:Aging / Q000378:metabolism; D000818:Animals; D001596:Benzylamines / Q000378:metabolism; D001812:Blood-Brain Barrier; D001921:Brain / Q000098:blood supply / Q000254:growth & development*; D002540:Cerebral Cortex / Q000201:enzymology; D003010:Clorgyline / Q000494:pharmacology; D008833:Microcirculation / Q000201:enzymology / Q000254:growth & development; D008995:Monoamine Oxidase / Q000378:metabolism*; D008996:Monoamine Oxidase Inhibitors / Q000494:pharmacology; D010293:Pargyline / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012642:Selegiline / Q000494:pharmacology; D013379:Substrate Specificity; D014363:Tryptamines / Q000378:metabolism
chemical_list: D001596:Benzylamines; D008996:Monoamine Oxidase Inhibitors; D014363:Tryptamines; D012642:Selegiline; C030820:tryptamine; D010293:Pargyline; C030796:benzylamine; D008995:Monoamine Oxidase; D003010:Clorgyline