Serotonin/norepinephrine/dopamine transporter + 5-HT2A receptor

Class

Multimodal reuptake inhibitor

This mechanism targets four proteins involved in signaling by the brain's monoamine neurotransmitters: the transporters that recycle serotonin, norepinephrine, and dopamine back into the neurons that released them (SERT, NET, and DAT), and a receptor, 5-HT2A, that serotonin activates on downstream neurons. Blocking the three transporters slows the removal of these neurotransmitters from the space between neurons, raising the amount available to bind receptors and sustain signaling over time. Serotonin, norepinephrine, and dopamine each regulate distinct but overlapping aspects of mood, motivation, alertness, and cognition, so acting on all three transporters simultaneously is intended to influence a broader range of these symptom domains than a single-transporter drug would. Adding antagonism at the 5-HT2A receptor is meant to shape how the resulting rise in serotonin is interpreted downstream, since this receptor influences circuits involved in anxiety, sleep, and cortical arousal. Combining transporter inhibition with this receptor-level modulation is the defining feature of the 'multimodal' class, and reflects an approach to depression and related mood disorders that goes beyond the single-neurotransmitter reuptake-inhibition strategy of earlier antidepressant classes.