Serotonin transporter (SERT) (SERT)

The Serotonin transporter (SERT), encoded by the SLC6A4 gene, is a member of the solute carrier family 6 (SLC6) and serves as the primary mechanism for terminating serotonergic neurotransmission by transporting serotonin from the synaptic cleft back into the presynaptic neuron [1]. As a sodium-dependent symporter, its activity is driven by the transmembrane electrochemical gradient of sodium ions [1, 2]. SERT is a high-value therapeutic target in psychiatry, as its inhibition increases the residence time of serotonin in the synapse, thereby alleviating symptoms of major depressive disorder, anxiety, and obsessive-compulsive disorder [2]. Hyperforin, the primary antidepressant constituent of St. John's Wort, interacts with SERT through a mechanism distinct from traditional Selective Serotonin Reuptake Inhibitors (SSRIs) [3]. While SSRIs typically bind to the substrate-binding site or allosteric sites on the transporter, hyperforin acts by activating TRPC6 cation channels, leading to an influx of sodium and calcium ions [4]. This elevation of intracellular sodium reduces the driving force for SERT-mediated transport, resulting in a non-selective inhibition of serotonin, dopamine, and norepinephrine reuptake [3, 4]. Understanding this interaction is crucial for managing the significant drug-drug interaction profile of hyperforin, which also involves the induction of metabolic enzymes like CYP3A4 [3]. [1] UniProt (P31645); [2] StatPearls (Selective Serotonin Reuptake Inhibitors); [3] Müller (2003) Pharmacopsychiatry; [4] Singer et al. (1999) J Pharmacol Exp Ther.

Other names

SLC6A45-HTTSodium-dependent serotonin transporter5-hydroxytryptamine transporter

Inhibition of serotonin reuptake from the synaptic cleft into the presynaptic neuron, thereby increasing the extracellular concentration of serotonin and enhancing serotonergic neurotransmission [2, 3]. Hyperforin specifically inhibits reuptake by elevating intracellular sodium concentrations, which reduces the transmembrane sodium gradient necessary for transporter function [4].