Dopamine breakdown
Monoamine oxidase B (MAO-B)
Also searched as Monoamine oxidase B (MAO-B).
Dopamine is degraded by both isoforms, but MAO-B is the higher-affinity route and the one that dominates in the brain. Slow it and dopamine persists longer in the synapse — the mechanism behind selegiline and rasagiline in Parkinson's disease. Two things follow that are worth knowing. Selective MAO-B inhibition raises dopamine without the tyramine food interaction that MAO-A inhibition carries. And because the enzyme generates hydrogen peroxide while it works, slowing it lowers an oxidative burden as well as preserving a transmitter.
In depth
Monoamine oxidase B, the isoform concentrated in brain, liver and platelets. It has a high affinity for dopamine and phenethylamine, and its activity in the brain rises with age.
What drives it
Cellular aging increases it.
MAO-B activity and expression rise with AGE, particularly in glia, which is why MAO-B selective inhibitors are used in age-related movement disorders while MAO-A inhibitors are not. Supplying the upstream so the pathway is not an orphan. an age-association, not an intervention finding, and it makes no claim that any ingredient alters the age trajectory. StatPearls NBK539848 ; Sci Rep 2022. PMC8742005
What it drives
It reduces Motivation.
10.1186/s12881-017-0469-5 — MAO-B is sensitive to selegiline and displays a higher affinity for phenethylamine and dopamine; it is found primarily in the brain, liver and platelets. dopamine is a substrate of both isoforms, so MAO-B is the higher-affinity route, not the only one. Sci Rep 2022, PMC8742005 — Phenethylamine is a substrate of monoamine oxidase B in the paraventricular thalamic nucleus ; StatPearls NBK539848 — Monoamine Oxidase Inhibitors. doi 10.1186/s12881-017-0469-5 · PMC8742005
Blends that modulate it
Each blend page names this pathway and carries the study behind its claim.
See it on the map
Open the causal map to follow this pathway upstream and downstream, arrow by arrow, each with its study.