Gene Organization and Polymorphisms of Monoamine Transporters

The monoamine neurotransmitters norepinephrine (NE), dopamine (DA), and serotonin (5-HT), play important roles in mood, cognition, learning, motor activity, reward, sleep, appetite, and cardiovascular functions. The availability of extracellular NE, DA, and 5-HT is limited by presynaptically localized transporters—NET, DAT, and SERT, respectively. The MA transporters retrieve released neurotransmitter, thus limiting the spread and duration of synaptic excitability and allowing neurotransmitter to be repackaged into synaptic vesicles. NET and SERT are the targets for many antidepressants, such as the tricyclic agents and the selective serotonin reuptake inhibitors (SSRIs) and with DAT, are the targets for the psychostimulants amphetamine and cocaine (1).