Classification and Mechanism of Action
Start with the big picture
Most antidepressant classes enhance monoaminergic signaling in limbic and frontal circuits, but they do so through distinct targets. SSRIs inhibit SERT, while SNRIs and TCAs affect both serotonin and norepinephrine reuptake; TCAs also act at several receptor types. MAO inhibitors reduce monoamine degradation, whereas other agents combine transporter effects with receptor agonism or antagonism. The snapshot also covers mechanisms involving dopamine transport, melatonin receptors, and NMDA receptors. These distinctions help organize the many drug classes by mechanism rather than name alone. Although neurotransmitter changes occur at the target level, clinical response typically lags by about two to four weeks, reflecting downstream neuroadaptive changes.
What you'll learn
- Classify antidepressants by their principal transporter, enzyme, or receptor targets.
- Describe how SERT, NET, DAT, and MAO inhibition affect monoamine signaling.
- Differentiate reuptake inhibitors from agents with important receptor actions.
- Summarize mechanisms involving NMDA and melatonin receptors.
- Explain the distinction between early neurotransmitter effects and delayed clinical response.
Continue your study
Work through the complete notes and reinforce the topic with the study tools available in the full lesson.
