5-HT3 receptor

The 5-HT₃ receptor belongs to the Cys-loop superfamily of ligand-gated ion channels (LGICs) and therefore differs structurally and functionally from all other 5-HT receptors (5-hydroxytryptamine, or serotonin receptors) which are G protein-coupled receptors.^[1]^[2]^[3] This ion channel is cation-selective and mediates neuronal depolarization and excitation within the central and peripheral nervous systems.^[1]

As with other ligand gated ion channels, the 5-HT₃ receptor consists of five subunits arranged around a central ion conducting pore, which is permeable to sodium (Na), potassium (K), and calcium (Ca) ions. Binding of the neurotransmitter 5-hydroxytryptamine (serotonin) to the 5-HT₃ receptor opens the channel, which, in turn, leads to an excitatory response in neurons. The rapidly activating, desensitizing, inward current is predominantly carried by sodium and potassium ions.^[2] 5-HT₃ receptors have a negligible permeability to anions.^[1] They are most closely related by homology to the nicotinic acetylcholine receptor.

^ ^a ^b ^c Barnes NM, Hales TG, Lummis SC, Peters JA (January 2009). "The 5-HT3 receptor--the relationship between structure and function". Neuropharmacology. 56 (1): 273–284. doi:10.1016/j.neuropharm.2008.08.003. PMC 6485434. PMID 18761359.
^ ^a ^b Thompson AJ, Lummis SC (2006). "5-HT3 Receptors". Current Pharmaceutical Design. 12 (28): 3615–3630. doi:10.2174/138161206778522029. PMC 2664614. PMID 17073663.
^ Reeves DC, Lummis SC (2002). "The molecular basis of the structure and function of the 5-HT3 receptor: a model ligand-gated ion channel (review)". Molecular Membrane Biology. 19 (1): 11–26. doi:10.1080/09687680110110048. PMID 11989819. S2CID 36985954.

[Barnes-1] Barnes NM, Hales TG, Lummis SC, Peters JA (January 2009). "The 5-HT3 receptor--the relationship between structure and function". Neuropharmacology. 56 (1): 273–284. doi:10.1016/j.neuropharm.2008.08.003. PMC 6485434. PMID 18761359.

[Thompson-2] Thompson AJ, Lummis SC (2006). "5-HT3 Receptors". Current Pharmaceutical Design. 12 (28): 3615–3630. doi:10.2174/138161206778522029. PMC 2664614. PMID 17073663.

[Reeves_2002-3] Reeves DC, Lummis SC (2002). "The molecular basis of the structure and function of the 5-HT3 receptor: a model ligand-gated ion channel (review)". Molecular Membrane Biology. 19 (1): 11–26. doi:10.1080/09687680110110048. PMID 11989819. S2CID 36985954.

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