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Developmental aspects of the monoamine-degrading enzyme monoamine oxidase
M Strolin Benedetti1, P Dostert, K F Tipton
1Farmitalia Carlo Erba, R&D-Erbamont Group, Milan, Italy.
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.
Insights
Monoamine oxidase (MAO) activity shows varied developmental patterns in rat and mouse tissues. MAO-A and MAO-B enzyme development differs significantly across species and organs, requiring further research.
Area of Science:
- Biochemistry
- Developmental Biology
- Pharmacology
Background:
- Monoamine oxidase (MAO) enzymes, specifically MAO-A and MAO-B, play crucial roles in neurotransmitter metabolism.
- Understanding the ontogenesis of MAO activity is vital for comprehending developmental processes and potential therapeutic interventions.
Purpose of the Study:
- To review and synthesize existing data on the developmental patterns of MAO-A and MAO-B activity in various mammalian tissues.
- To highlight species-specific and tissue-specific differences in MAO enzyme ontogeny.
Main Methods:
- Literature review of studies investigating MAO activity during development in rats, mice, and humans.
- Comparative analysis of MAO-A and MAO-B activity across different tissues (heart, kidney, liver, lung, brain) and developmental stages.
Main Results:
- Rat heart exhibits predominant MAO-B in young animals, with MAO-A increasing with age, contrasting with mouse heart MAO-B patterns.
- MAO activity reaches adult levels early in rat kidney and liver, but lung MAO-A matures by day 40, while MAO-B continues to increase.
- Rodent and human brain development shows parallels in MAO-A and MAO-B ontogeny, with a decreasing MAO-A/MAO-B ratio during postnatal development.
Conclusions:
- Significant variations exist in the developmental trajectories of MAO-A and MAO-B across mammalian species and tissues.
- Methodological limitations in current studies necessitate caution in interpreting findings and underscore the need for further research.
- Reliable data on MAO ontogenesis in mammalian tissues are crucial for advancing our understanding of neurodevelopment and related disorders.