5-Hydroxytryptamine receptor 2B (5-HT2B) also known as serotonin receptor 2B is a protein that in humans is encoded by the HTR2B gene.[5][6] 5-HT2B is a member of the 5-HT2 receptor family that binds the neurotransmitter serotonin (5-hydroxytryptamine, 5-HT). Like all 5-HT2 receptors, the 5-HT2B receptor is Gq/G11-protein coupled, leading to downstream activation of phospholipase C.
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First discovered in the stomach of rats, 5-HT2B was challenging to characterize initially because of its structural similarity to the other 5-HT2 receptors, particularly 5-HT2C.[7] The 5-HT2 receptors (of which the 5-HT2B receptor is a subtype) mediate many of the central and peripheral physiologic functions of serotonin. Cardiovascular effects include contraction of blood vessels and shape changes in platelets; central nervous system (CNS) effects include neuronal sensitization to tactile stimuli and mediation of some of the effects of hallucinogenic substituted amphetamines. The 5-HT2B receptor is expressed in several areas of the CNS, including the dorsal hypothalamus, frontal cortex, medial amygdala, and meninges.[8] However, its most important role is in the peripheral nervous system (PNS) where it maintains the viability and efficiency of the cardiac valve leaflets.[9]
The 5-HT2B receptor subtype is involved in:
- CNS: inhibition of serotonin and dopamine uptake, behavioral effects[10]
- Vascular: pulmonary vasoconstriction[11]
- Cardiac: The 5-HT2B receptor regulates cardiac structure and functions, as demonstrated by the abnormal cardiac development observed in 5-HT2B receptor null mice.[12] Excessive stimulation of this receptor causes pathological proliferation of cardiac valve fibroblasts,[13] with chronic overstimulation leading to valvulopathy.[14][15] These receptors are also overexpressed in human failing heart and antagonists of 5-HT2B receptors were discovered to prevent both angiotensin II or beta-adrenergic agonist-induced pathological cardiac hypertrophy in mouse.[16][17][18]
- Serotonin transporter: 5-HT2B receptors regulate serotonin release via the serotonin transporter, and are important both to normal physiological regulation of serotonin levels in blood plasma,[19] and with the abnormal acute serotonin release produced by drugs such as MDMA.[10] Surprisingly, however, 5-HT2B receptor activation appears to be protective against the development of serotonin syndrome following elevated extracellular serotonin levels,[20] despite its role in modulating serotonin release.
5-HT2B receptors have been strongly implicated in causing drug-induced valvular heart disease.[21][22][23] The Fen-Phen scandal in the 80s and 90s revealed the cardiotoxic effects of 5-HT2B stimulation.[24] Today, 5-HT2B agonism is considered a toxicity signal precluding further clinical development of a compound.[25]
The structure of the 5-HT2B receptor was resolved in a complex with the valvulopathogenic drug ergotamine.[26] As of 2009, few highly selective 5-HT2B receptor ligands have been discovered, although numerous potent non-selective compounds are known, particularly agents with concomitant 5-HT2C binding. Research in this area has been limited due to the cardiotoxicity of 5-HT2B agonists, and the lack of clear therapeutic application for 5-HT2B antagonists, but there is still a need for selective ligands for scientific research.[27]
Agonists
- Selective
- Non-selective
Antagonists
- Agomelatine – primarily a melatonin MT1/MT2 receptor agonist, with a less potent antagonism of 5-HT2B and 5-HT2C[36]
- Amisulpride
- Aripiprazole
- Cariprazine[37]
- Clozapine
- Cyproheptadine
- mCPP (in humans)
- Sarpogrelate – a mixed 5-HT2A/B antagonist
- Lisuride – a dopamine agonist of the ergoline class, that is also a 5-HT2B antagonist[38] and a dual 5-HT2A/C agonist[39]
- Tegaserod – primarily a 5-HT4 agonist, but also a 5-HT2B antagonist[40]
- RS-127,445[41] – high affinity; subtype selective (1000×), selective over at least eight other 5-HTR types; orally bioavailable
- Metadoxine – a 5-HT2B antagonist and GABA-activity modulator[42]
- SDZ SER-082 – a mixed 5-HT2B/C antagonist
- Promethazine[43]
- EGIS-7625 – high selectivity over 5-HT2A[44]
- PRX-08066
- SB-200,646
- SB-204,741
- SB-206,553 – mixed 5-HT2B/C antagonist and PAM at α7 nAChR[45]
- SB-215,505[46]
- SB-228,357
- Terguride – an oral, potent antagonist of 5-HT2A and 5-HT2B receptors
- LY-266,097
- LY-272,015
5-HT2B antagonists have previously been proposed as treatment for migraine headaches, and RS-127,445 was trialled in humans up to Phase I for this indication, but development was not continued.[47] More recent research has focused on possible application of 5-HT2B antagonists as treatments for chronic heart disease.[48][49] Research claims serotonin 5-HT2B receptors have effect on liver regeneration.[50] Antagonism of 5-HT2B may attenuate fibrogenesis and improve liver function in disease models in which fibrosis is pre-established and progressive.
Elangbam CS, Job LE, Zadrozny LM, Barton JC, Yoon LW, Gates LD, et al. (Aug 2008). "5-hydroxytryptamine (5HT)-induced valvulopathy: compositional valvular alterations are associated with 5HT2B receptor and 5HT transporter transcript changes in Sprague-Dawley rats". Experimental and Toxicologic Pathology. 60 (4–5): 253–62. doi:10.1016/j.etp.2008.03.005. PMID 18511249.
Padhariya K, Bhandare R, Canney D, Velingkar V (2017-12-12). "Cardiovascular Concern of 5-HT2B Receptor and Recent Vistas in the Development of Its Antagonists". Cardiovascular & Hematological Disorders Drug Targets. 17 (2): 86–104. doi:10.2174/1871529X17666170703115111. PMID 28676029.
Fitzgerald LW, Burn TC, Brown BS, Patterson JP, Corjay MH, Valentine PA, et al. (Jan 2000). "Possible role of valvular serotonin 5-HT(2B) receptors in the cardiopathy associated with fenfluramine". Molecular Pharmacology. 57 (1): 75–81. PMID 10617681.
Cavero I, Guillon JM (2014-03-01). "Safety Pharmacology assessment of drugs with biased 5-HT(2B) receptor agonism mediating cardiac valvulopathy". Journal of Pharmacological and Toxicological Methods. 69 (2): 150–161. doi:10.1016/j.vascn.2013.12.004. PMID 24361689.
Görnemann T, Hübner H, Gmeiner P, Horowski R, Latté KP, Flieger M, et al. (Mar 2008). "Characterization of the molecular fragment that is responsible for agonism of pergolide at serotonin 5-Hydroxytryptamine2B and 5-Hydroxytryptamine2A receptors". The Journal of Pharmacology and Experimental Therapeutics. 324 (3): 1136–45. doi:10.1124/jpet.107.133165. PMID 18096760. S2CID 24907300.
Millan MJ, Gobert A, Lejeune F, Dekeyne A, Newman-Tancredi A, Pasteau V, et al. (Sep 2003). "The novel melatonin agonist agomelatine (S20098) is an antagonist at 5-hydroxytryptamine2C receptors, blockade of which enhances the activity of frontocortical dopaminergic and adrenergic pathways". The Journal of Pharmacology and Experimental Therapeutics. 306 (3): 954–64. doi:10.1124/jpet.103.051797. PMID 12750432. S2CID 18753440.
Hofmann C, Penner U, Dorow R, Pertz HH, Jähnichen S, Horowski R, et al. (2006). "Lisuride, a dopamine receptor agonist with 5-HT2B receptor antagonist properties: absence of cardiac valvulopathy adverse drug reaction reports supports the concept of a crucial role for 5-HT2B receptor agonism in cardiac valvular fibrosis". Clinical Neuropharmacology. 29 (2): 80–6. doi:10.1097/00002826-200603000-00005. PMID 16614540. S2CID 33849447.
Egan CT, Herrick-Davis K, Miller K, Glennon RA, Teitler M (Apr 1998). "Agonist activity of LSD and lisuride at cloned 5HT2A and 5HT2C receptors". Psychopharmacology. 136 (4): 409–14. doi:10.1007/s002130050585. PMID 9600588. S2CID 3021798.
Dunlop J, Lock T, Jow B, Sitzia F, Grauer S, Jow F, et al. (Mar 2009). "Old and new pharmacology: positive allosteric modulation of the alpha7 nicotinic acetylcholine receptor by the 5-hydroxytryptamine(2B/C) receptor antagonist SB-206553 (3,5-dihydro-5-methyl-N-3-pyridinylbenzo[1,2-b:4,5-b']di pyrrole-1(2H)-carboxamide)". The Journal of Pharmacology and Experimental Therapeutics. 328 (3): 766–76. doi:10.1124/jpet.108.146514. PMID 19050173. S2CID 206500076.
Poissonnet G, Parmentier JG, Boutin JA, Goldstein S (Mar 2004). "The emergence of selective 5-HT 2B antagonists structures, activities and potential therapeutic applications". Mini Reviews in Medicinal Chemistry. 4 (3): 325–30. doi:10.2174/1389557043487312. PMID 15032678.
Moss N, Choi Y, Cogan D, Flegg A, Kahrs A, Loke P, et al. (Apr 2009). "A new class of 5-HT2B antagonists possesses favorable potency, selectivity, and rat pharmacokinetic properties". Bioorganic & Medicinal Chemistry Letters. 19 (8): 2206–10. doi:10.1016/j.bmcl.2009.02.126. PMID 19307114.
- Raymond JR, Mukhin YV, Gelasco A, Turner J, Collinsworth G, Gettys TW, et al. (2002). "Multiplicity of mechanisms of serotonin receptor signal transduction". Pharmacology & Therapeutics. 92 (2–3): 179–212. doi:10.1016/S0163-7258(01)00169-3. PMID 11916537.
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- Schmuck K, Ullmer C, Engels P, Lübbert H (Mar 1994). "Cloning and functional characterization of the human 5-HT2B serotonin receptor". FEBS Letters. 342 (1): 85–90. doi:10.1016/0014-5793(94)80590-3. PMID 8143856. S2CID 11232259.
- Launay JM, Birraux G, Bondoux D, Callebert J, Choi DS, Loric S, et al. (Feb 1996). "Ras involvement in signal transduction by the serotonin 5-HT2B receptor". The Journal of Biological Chemistry. 271 (6): 3141–7. doi:10.1074/jbc.271.6.3141. PMID 8621713.
- Le Coniat M, Choi DS, Maroteaux L, Launay JM, Berger R (Feb 1996). "The 5-HT2B receptor gene maps to 2q36.3-2q37.1" (PDF). Genomics. 32 (1): 172–3. doi:10.1006/geno.1996.0101. PMID 8786115.
- Kim SJ, Veenstra-VanderWeele J, Hanna GL, Gonen D, Leventhal BL, Cook EH (Feb 2000). "Mutation screening of human 5-HT(2B)receptor gene in early-onset obsessive-compulsive disorder". Molecular and Cellular Probes. 14 (1): 47–52. doi:10.1006/mcpr.1999.0281. PMID 10722792.
- Manivet P, Mouillet-Richard S, Callebert J, Nebigil CG, Maroteaux L, Hosoda S, et al. (Mar 2000). "PDZ-dependent activation of nitric-oxide synthases by the serotonin 2B receptor". The Journal of Biological Chemistry. 275 (13): 9324–31. doi:10.1074/jbc.275.13.9324. PMID 10734074.
- Becamel C, Figge A, Poliak S, Dumuis A, Peles E, Bockaert J, et al. (Apr 2001). "Interaction of serotonin 5-hydroxytryptamine type 2C receptors with PDZ10 of the multi-PDZ domain protein MUPP1". The Journal of Biological Chemistry. 276 (16): 12974–82. doi:10.1074/jbc.M008089200. PMID 11150294.
- Manivet P, Schneider B, Smith JC, Choi DS, Maroteaux L, Kellermann O, et al. (May 2002). "The serotonin binding site of human and murine 5-HT2B receptors: molecular modeling and site-directed mutagenesis". The Journal of Biological Chemistry. 277 (19): 17170–8. doi:10.1074/jbc.M200195200. PMID 11859080.
- Borman RA, Tilford NS, Harmer DW, Day N, Ellis ES, Sheldrick RL, et al. (Mar 2002). "5-HT(2B) receptors play a key role in mediating the excitatory effects of 5-HT in human colon in vitro". British Journal of Pharmacology. 135 (5): 1144–51. doi:10.1038/sj.bjp.0704571. PMC 1573235. PMID 11877320.
- Matsuda A, Suzuki Y, Honda G, Muramatsu S, Matsuzaki O, Nagano Y, et al. (May 2003). "Large-scale identification and characterization of human genes that activate NF-kappaB and MAPK signaling pathways". Oncogene. 22 (21): 3307–18. doi:10.1038/sj.onc.1206406. PMID 12761501. S2CID 38880905.
- Slominski A, Pisarchik A, Zbytek B, Tobin DJ, Kauser S, Wortsman J (Jul 2003). "Functional activity of serotoninergic and melatoninergic systems expressed in the skin". Journal of Cellular Physiology. 196 (1): 144–53. doi:10.1002/jcp.10287. PMID 12767050. S2CID 24534729.
- Lin Z, Walther D, Yu XY, Drgon T, Uhl GR (Dec 2004). "The human serotonin receptor 2B: coding region polymorphisms and association with vulnerability to illegal drug abuse". Pharmacogenetics. 14 (12): 805–11. doi:10.1097/00008571-200412000-00003. PMID 15608559.
- "5-HT2B". IUPHAR Database of Receptors and Ion Channels. International Union of Basic and Clinical Pharmacology. Archived from the original on 2017-02-02. Retrieved 2008-11-25.
- Human HTR2B genome location and HTR2B gene details page in the UCSC Genome Browser.
- Overview of all the structural information available in the PDB for UniProt: P41595 (5-hydroxytryptamine receptor 2B) at the PDBe-KB.
This article incorporates text from the United States National Library of Medicine, which is in the public domain.