SLC6A2 and major depressive disorder: The norepinephrine transporter (NET), which is also known as solute carrier family 6 member 2 (SLC6A2), is responsible for norepinephrine re-uptake by the presynaptic terminal, and is a target for tricyclic antidepressants, selective norepinephrine re-uptake inhibitors, and serotonin-NE re-uptake inhibitors used to treat major depressive disorder (MDD) [3, 4].