Serotonin signaling system (5-HT system)

The serotonin (5-hydroxytryptamine or 5-HT) signaling system is a comprehensive physiological network comprising various receptors, transporters, and biosynthetic enzymes that mediate the effects of the neurotransmitter serotonin. Serotonin is primarily synthesized in the raphe nuclei of the brainstem and the enterochromaffin cells of the gastrointestinal tract, where it regulates a diverse array of functions including mood, sleep, appetite, and intestinal motility [StatPearls: Serotonin]. The system includes seven distinct families of receptors (5-HT1 to 5-HT7), most of which are G protein-coupled receptors, while the 5-HT3 receptor functions as a ligand-gated ion channel [NCBI: Serotonin Receptors]. In addition to receptors, the serotonin transporter (SERT) is a key component responsible for the reuptake of serotonin from the synaptic cleft, serving as the primary target for many antidepressant medications [PubMed: Serotonin Transporter]. Dysregulation of this system is linked to a wide range of conditions, such as major depressive disorder, anxiety, migraine, and irritable bowel syndrome [NIH: Serotonin and Disease]. Pharmacological intervention in the 5-HT system is highly varied, utilizing agonists, antagonists, and reuptake inhibitors to modulate signaling for therapeutic benefit across psychiatric, neurological, and gastrointestinal medicine [Nature: Serotonin Signaling].

Other names

5-hydroxytryptamine signaling systemSerotonergic system5-HT systemSerotonin pathway

Modulation of serotonergic neurotransmission through selective serotonin reuptake inhibition (SSRI), serotonin-norepinephrine reuptake inhibition (SNRI), direct receptor agonism (e.g., 5-HT1A, 5-HT1B/1D), receptor antagonism (e.g., 5-HT2A, 5-HT3), and inhibition of monoamine oxidase (MAO).