Vesicular monoamine transporter

The vesicular monoamine transporter (VMAT) is a transport protein integrated into the membrane of intracellular vesicles of presynaptic neurons. It acts to transport monoamines into the synaptic vesicles.

Isoforms
The two isoforms are:
 * VMAT1
 * VMAT2

Monoamines
Monoamines transported by VMATs are mainly noradrenaline, adrenaline and isoprenaline. However, other substrates include dopamine, 5-HT, guanethidine and MPP+.

Clinical significance
VMAT can be inhibited by reserpine, tetrabenazine and ibogaine.

VMAT is the main target of methamphetamine. By acting as a competitive antagonist, methamphetamine blocks the presynaptic cell's ability to use VMAT to package the above mentioned neurotransmitters into vesicles. The result is increased neurotransmitter release that is not dependent on the phasic activity of the presynaptic cell.