Vesicular monoamine transporters (VMAT) are transmembrane proteins located on membranes of monoaminergic neurons and are responsible for the uptake of cytosolic monoamines into synaptic vesicles. They store neurotransmitter molecules in synaptic vesicles for additional cycles of release. They are acidic glycoproteins encoded by the SLC18A1 gene and transport neurotransmitters including dopamine, serotonin, adrenaline, noradrenaline, histamine and norepinephrine^1,2. Its structure is composed of 12 transmembrane domains, the C and N-terminus are located in the cytosolic side of the vesicle. The glycosylation sites are located in the vesicular matrix on a loop between transmembrane domain I and II¹.

VMAT have an important role in sorting and releasing of neurotransmitters and in the adjustment of neuronal and endocrine informational output.  The transport into the storage organelle is dependent on a vacuolar ATPase-generated proton gradient in exchange for protons.

Two monoamine transporters have been identified in rats and in human: VMAT1 and VMAT2. In humans, VMAT1 is preferentially expressed in large dense core vesicles of various neuroendocrine cells, including chromaffin and enterochromaffin cells.

Several studies have suggested that VMAT1 has a strong connection to schizophrenia, bipolar disorder, and other anxiety related personality disorders, partially due to the fact that VMAT1 maps to chromosome 8p21.3, a locus with strong evidence for linkage with schizophrenia^1,3_.