5-Hydroxytryptamine receptor (5-HT receptor) (5-HTR)

5-Hydroxytryptamine (5-HT) receptors, or serotonin receptors, are a diverse group of signaling proteins that play a fundamental role in gastrointestinal (GI) physiology. Approximately 95% of the body's serotonin is located within the gut, primarily stored in enterochromaffin cells and enteric neurons (Gershon & Tack, 2007). These receptors are classified into several families, with 5-HT3 (a ligand-gated ion channel) and 5-HT4 (a G protein-coupled receptor) being the most clinically significant targets in the GI tract (Mawe & Hoffman, 2013). They mediate critical functions such as peristalsis, intestinal secretion, and the transmission of sensory information like pain and nausea to the brain (Camilleri, 2009). Dysregulation of the serotonergic system is a key factor in the pathophysiology of functional GI disorders, including irritable bowel syndrome (IBS) and chronic constipation (Sanger & Gummer, 2017). Consequently, drugs targeting these receptors, such as 5-HT3 antagonists for emesis and 5-HT4 agonists for motility, are essential therapeutic agents in gastroenterology (Ford et al., 2014).

Other names

Serotonin receptor5-HT receptorEnteric serotonin receptor5-Hydroxytryptamine receptor family

Drugs targeting these receptors act as either antagonists or agonists to modulate enteric nervous system activity. 5-HT3 receptor antagonists block serotonin-induced depolarization of vagal afferent nerves, thereby inhibiting the vomiting reflex and slowing colonic transit (Sanger & Gummer, 2017). Conversely, 5-HT4 receptor agonists stimulate the release of excitatory neurotransmitters like acetylcholine from enteric motor neurons, which enhances the peristaltic reflex and promotes gastrointestinal motility (Mawe & Hoffman, 2013).