SLC6A3 and schizophrenia: In considering potential molecular mechanisms involved in abnormal dopamine neurotransmission in schizophrenia, it is significant that the dopamine transporter (DAT: gene name = Solute Carrier Family 6 Member 3; SLC6A3) is located on the presynaptic membrane of dopaminergic terminals and regulates dopamine neurotransmission by removing dopamine from the synaptic cleft.11 Studies using DAT knock out mice have shown these animals display a persistent increase in extracellular dopamine,12,13 which adds to the argument that DAT is an important regulator of synaptic dopamine concentration.