Vesicular monoamine transporter 2 (VMAT2) (VMAT2)

Vesicular monoamine transporter 2 (VMAT2), encoded by the SLC18A2 gene, is an integral membrane protein responsible for the ATP-dependent transport of monoamine neurotransmitters—including norepinephrine, dopamine, and serotonin—from the cellular cytosol into synaptic vesicles (UniProt, 2024). Located primarily within the central and peripheral nervous systems, VMAT2 plays a critical role in protecting neurotransmitters from metabolic degradation by monoamine oxidase and preparing them for regulated exocytotic release (StatPearls, 2023). In presynaptic noradrenergic terminals, it is the definitive mechanism for catecholamine storage, maintaining the pool of norepinephrine required for sympathetic signaling (PubMed, 2004). Dysregulation of VMAT2 is implicated in various neurological and psychiatric conditions, including Parkinson's disease and VMAT2 deficiency syndrome (NIH, 2021). Therapeutically, VMAT2 inhibitors such as tetrabenazine and valbenazine are used to manage hyperkinetic movement disorders like tardive dyskinesia and Huntington's chorea by reducing the amount of dopamine available for release (FDA, 2017). However, because it also affects norepinephrine and serotonin, its inhibition can lead to significant safety concerns, including depression, parkinsonism, and orthostatic hypotension (StatPearls, 2023).

Other names

Solute carrier family 18 member 2SLC18A2Vesicular amine transporter 2VAT2Monoamine transporter

VMAT2 inhibitors bind to the transporter and prevent the translocation of monoamines from the cytoplasm into synaptic vesicles. This leads to the accumulation of neurotransmitters in the cytosol, where they are rapidly degraded by monoamine oxidase (MAO), resulting in a depletion of the neurotransmitter stores available for release into the synaptic cleft (StatPearls, 2023).