The serotonin synapse
Where SSRIs, SNRIs, and serotonin syndrome all live.
Click any node for its role, or open a question below to light the causal path.
Read this pathway as text
Serotonergic neurons release serotonin (5-HT) into the synapse, where it stimulates postsynaptic receptors before being recycled by the serotonin transporter (SERT) back into the presynaptic terminal, and degraded by monoamine oxidase (MAO). SSRIs block SERT, raising synaptic serotonin immediately; the antidepressant effect follows weeks later as postsynaptic receptors adapt. SNRIs add noradrenaline transporter blockade. MAO inhibitors block degradation; combining MAO inhibition with reuptake inhibition floods the synapse. Serotonin syndrome (agitation, clonus, hyperthermia). Tramadol, linezolid, and triptans are the commonly missed serotonergic co-conspirators.
Keep going
Last reviewed 2026-08-15 · Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed.