Developmental Aspects of the Monoamine-Degrading Enzyme Monoamine Oxidase

Abstract

In the rat heart, monoamine oxidase (MAO)-B activity was shown to predominate in 2- to 3-week-old animals, whereas MAO-A activity was reported to be very low in newborn rats and to increase considerably with age until it predominates. These results are in contrast with those found in the mouse heart, where an age-dependent increase in MAO-B activity with no changes in 5-hydroxytryptamine deaminating activity was found to occur. There is evidence that the adult values of MAO activity are reached early in development in rat kidney and liver. In the rat lung the adult values of MAO-A activity are reached by day 40, whereas MAO-B activity is still increasing by day 80. Important differences have been reported in the developmental pattern of the two forms of MAO in the rat and mouse brain, with a decrease in the MAO-A/MAO-B ratio during postnatal development. In the human brain, the ontogenetic development of MAO-A and MAO-B appears to parallel that observed in the rodent brain. It is worth noting that most of the available data have to be considered with reservation owing to many methodological problems. Further studies are clearly needed to get reliable information on the ontogenesis of MAO in mammalian tissues.

Importance of Mitochondria in Cardiac Pathologies: Focus on Uncoupling Proteins and Monoamine Oxidases

“…Species-dependent cardiomyocytes express different MAO isoforms: in rats, MAO-A predominates in adulthood, [ 116 , 117 ] while in adult mice MAO-B dominates [ 118 , 119 ]. Interestingly, in rat hearts, MAO-B activity also predominates up to an age of 2–3 weeks [ 120 ], most likely since MAO-B expression increases under mechanical strain as compared to the quiescent situation [ 121 ]. Human cardiomyocytes contain both MAO isoforms, but with more, albeit moderate, expression for MAO-A [ 122 , 123 ].…”

Inhibitory monoaminooksydazy (IMAO): farmakologia, metabolizm i zastosowanie w terapii depresji o różnej etiologii

“…Zdecydowanie mniej zainteresowania badaczy przyciągnął izoenzym MAO-A w obszarze swoich właściwości kinetycznych. Wykazano występowanie u niego również prostego mechanizmu podwójnego wypierania, bez żadnych dodatkowych reakcji kompleksu zredukowany enzym-produkt w zakresie reoksydacji, kiedy jako substrat zastosowano kynuraminę [6]. Niemniej jednak, kompleks zredukowany enzym-substrat powstawał przy wyższych stężeniach substratu i był szybciej odtleniany, niż wolny zredukowany enzym.…”

Drug metabolism and disposition in children

“…Monoamine oxidases (MAOs) are oxidative enzymes located in the mitochondria and involved in the metabolism of endogenous as well as exogenous compounds [99]. Monoamine oxidases (MAOs) are oxidative enzymes located in the mitochondria and involved in the metabolism of endogenous as well as exogenous compounds [99].…”

“…Monoamine oxidases. Monoamine oxidases (MAOs) are oxidative enzymes located in the mitochondria and involved in the metabolism of endogenous as well as exogenous compounds [99]. The ontogenetic development of MAO-A and MAO-B in the frontal cortex of human brain has been studied by Kornhuber et al [100].…”