Serotonin/norepinephrine/dopamine transporter

Class

Triple reuptake inhibitor

The serotonin transporter (SERT), norepinephrine transporter (NET), and dopamine transporter (DAT) are membrane proteins that remove their respective neurotransmitters from the synaptic space after release, ending the signal and allowing the neurotransmitter to be recycled. Triple reuptake inhibitors block all three transporters simultaneously, increasing the extracellular availability of serotonin, norepinephrine, and dopamine at nerve synapses. This class was conceived as a broader alternative to single- or dual-action antidepressants such as selective serotonin reuptake inhibitors or serotonin-norepinephrine reuptake inhibitors. The rationale is that mood, motivation, energy, and cognitive symptoms of depression are thought to draw on distinct but overlapping monoaminergic circuits: serotonin is linked to mood and anxiety regulation, norepinephrine to arousal and energy, and dopamine to motivation, reward, and concentration. By elevating all three neurotransmitters together, triple reuptake inhibitors aim to address a wider symptom profile, including anhedonia and fatigue, which are less reliably improved by serotonin-focused agents. This mechanism is studied mainly in mood disorders such as major depressive disorder, and has also been explored in conditions involving motivational or attentional deficits, given dopamine's role in those domains.