5-HT_2C receptor

The 5-HT_2C receptor is a subtype of the 5-HT2 receptor that binds the endogenous neurotransmitter serotonin (5-hydroxytryptamine, 5-HT). Like all 5-HT2 receptors, it is a G protein-coupled receptor (GPCR) that is coupled to G_q/G₁₁ and mediates excitatory neurotransmission. HTR2C denotes the human gene encoding for the receptor,^[4][5] that in humans is located on the X chromosome. As males have one copy of the gene and females have one of the two copies of the gene repressed, polymorphisms at this receptor can affect the two sexes to differing extent.

HTR2C
Identifiers
Aliases	HTR2C, 5-HT2C, 5-5HTR1C, 5-HT1C, 5-HT2C receptor, 5-hydroxytryptamine receptor 2C
External IDs	OMIM: 312861 MGI: 96281 HomoloGene: 20242 GeneCards: HTR2C
Gene location (Mouse) Chr. X chromosome (mouse)^[1] Band X F2|X 68.46 cM Start 145,745,509 bp^[1] End 145,980,273 bp^[1]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in external globus pallidus superior vestibular nucleus nucleus accumbens caudate nucleus middle frontal gyrus hypothalamus putamen Region I of hippocampus proper endothelial cell entorhinal cortex Top expressed in medial dorsal nucleus nucleus accumbens lateral hypothalamus dorsal tegmental nucleus dorsomedial hypothalamic nucleus medial vestibular nucleus olfactory tubercle ventral tegmental area subiculum substantia nigra More reference expression data BioGPS More reference expression data
Gene ontology Molecular function 1-(4-iodo-2,5-dimethoxyphenyl)propan-2-amine binding G protein-coupled receptor activity signal transducer activity G protein-coupled serotonin receptor activity Gq/11-coupled serotonin receptor activity serotonin binding neurotransmitter receptor activity Cellular component integral component of membrane membrane plasma membrane integral component of plasma membrane intracellular anatomical structure dendrite Biological process release of sequestered calcium ion into cytosol positive regulation of cytosolic calcium ion concentration involved in phospholipase C-activating G protein-coupled signaling pathway phospholipase C-activating serotonin receptor signaling pathway locomotory behavior positive regulation of phosphatidylinositol biosynthetic process cellular calcium ion homeostasis behavioral fear response regulation of nervous system process cGMP biosynthetic process phospholipase C-activating G protein-coupled receptor signaling pathway serotonin receptor signaling pathway feeding behavior positive regulation of ERK1 and ERK2 cascade regulation of corticotropin-releasing hormone secretion regulation of appetite positive regulation of fat cell differentiation signal transduction chemical synaptic transmission G protein-coupled receptor signaling pathway animal behaviour cGMP-mediated signaling G protein-coupled receptor signaling pathway, coupled to cyclic nucleotide second messenger Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 3358 15560 Ensembl n/a ENSMUSG00000041380 UniProt P28335 P34968 RefSeq (mRNA) NM_001256761 NM_000868 NM_001256760 NM_008312 RefSeq (protein) NP_000859 NP_001243689 NP_001243690 NP_032338 Location (UCSC) n/a Chr X: 145.75 – 145.98 Mb PubMed search ^[2] ^[3]
Wikidata
View/Edit Human View/Edit Mouse

Structure

At the cell surface the receptor exists as a homodimer.^[6] The crystal structure has been known since 2018.^[7]

Distribution

5-HT_2C receptors are located mainly in the choroid plexus,^[8] and in rats is also found in many other brain regions in high concentrations, including parts of the hippocampus, anterior olfactory nucleus, substantia nigra, several brainstem nuclei, amygdala, subthalamic nucleus and lateral habenula. 5-HT_2C receptors are also found on epithelial cells lining the ventricles.^[9]

Function

The 5-HT_2C receptor is one of the many binding sites for serotonin. Activation of this receptor by serotonin inhibits dopamine and norepinephrine release in certain areas of the brain.^[10]

5-HT_2C receptors are claimed to significantly regulate mood, anxiety, feeding, and reproductive behavior.^[11] 5-HT_2C receptors regulate dopamine release in the striatum, prefrontal cortex, nucleus accumbens, hippocampus, hypothalamus, and amygdala, among others.

Research indicates that some suicide victims have an abnormally high number of 5-HT_2C receptors in the prefrontal cortex.^[12] Agomelatine, which is a 5-HT_2C and 5-HT_2B antagonist as well as a MT₁ and MT₂ agonist, is an effective antidepressant.^[13][14] It has been called a norepinephrine-dopamine disinhibitor because antagonism of 5-HT_2C receptors by agomelatine results in an increase of dopamine and norepinephrine activity in the frontal cortex.^{[citation needed]} Conversely, many SSRIs (but not fluoxetine, which is a 5-HT_2C antagonist^[15]) indirectly stimulate 5-HT_2C activity by increasing levels of serotonin in the synapse although the delayed mood elevation that is usually typical of SSRIs is usually paralleled by the downregulation of the 5-HT_2C receptors.^[16] Many atypical antipsychotics block 5-HT_2C receptors, but their clinical use is limited by multiple undesirable actions on various neurotransmitters and receptors ^{[citation needed]}. Fluoxetine acts as a direct 5-HT_2C antagonist in addition to inhibiting serotonin reuptake, however, the clinical significance of this action is variable.^[15] Several tetracyclic antidepressants, including mirtazapine, are potent 5-HT_2C antagonists; this action may contribute to their efficacy.^[17][18][19]

An overactivity of 5-HT_2C receptors may contribute to depressive and anxiety symptoms in a certain population of patients. Activation of 5-HT_2C by serotonin is responsible for many of the negative side effects of SSRI and SNRI medications, such as sertraline, paroxetine, venlafaxine, and others. Some of the initial anxiety caused by SSRIs is due to excessive signalling at 5-HT_2C. Over a period of 1–2 weeks, the receptor begins to downregulate, along with the downregulation of 5-HT_2A, 5-HT1_A, and other serotonin receptors. This downregulation parallels the onset of the clinical benefits of SSRIs. 5-HT_2C receptors exhibit constitutive activity in vivo, and may retain the ability to influence neurotransmission in the absence of ligand occupancy. Thus, 5-HT_2C receptors do not require binding by a ligand (serotonin) in order to exhibit influence on neurotransmission. Inverse agonists may be required to fully extinguish 5-HT_2C constitutive activity, and may prove useful in the treatment of 5-HT_2C-mediated conditions in the absence of typical serotonin activity.^[16] In addition to the evidence for a role of 5-HT_2C receptor stimulation in depressive symptoms there also is evidence that activation of 5-HT_2C receptors may have beneficial effects upon certain aspects of depression, one group of researchers found that direct stimulation of 5-HT_2C receptors with a 5-HT_2C agonist reduced cognitive deficits in mice with a TPH2 loss-of-function mutation.^[20]

5-HT_2C receptors mediate the release and increase of extracellular dopamine in response to many drugs,^[21][22] including caffeine, nicotine, amphetamine, morphine, cocaine, and others. 5-HT_2C antagonism increases dopamine release in response to reinforcing drugs, and many dopaminergic stimuli. Feeding, social interaction, and sexual activity all release dopamine subject to inhibition of 5-HT_2C. Increased 5-HT_2C expression reduces dopamine release in both the presence and absence of stimuli.

Conditions that increase cytokine levels in the human body may have potential to raise 5-HT_2C gene expression in the brain. This could possibly comprise a link between viral infections and associated depression. Cytokine therapy has been shown to increase 5-HT_2C gene expression, resulting in increased activity of 5-HT_2C receptors in the brain ^{[citation needed]}.

Endocrinology

Serotonin is involved in basal and stress-induced regulation of hypothalamus and pituitary gland hormones such as prolactin, adrenocorticotropic hormone (ACTH), vasopressin and oxytocin, mainly via actions of receptor subtypes 5-HT_2A and 5-HT_2C.^[23] Therefore, the 5-HT_2C receptor is a significant modulator of the hypothalamic–pituitary–adrenal axis (HPA axis).^[24] The HPA axis is the main controller of acute sympathetic stress responses related to fight-or-flight response. Prolonged activation and disturbances of the HPA axis contribute to depressive and anxiety symptoms seen in many psychopathological conditions.

Stimulation of 5-HT_2C receptors leads to increase of corticotropin releasing hormone (CRH) and vasopressin mRNA in the paraventricular nucleus and proopiomelanocortin in the anterior pituitary lobe. In rats, restraint stress (which can produce depressive symptoms if being chronic) induces secretion of prolactin, ACTH, vasopressin and oxytocin which is partially mediated via 5-HT_2C receptor. Responses during such conditions as dehydration or haemorrhage causes the release oxytocin via serotonergic response that is partly mediated via 5-HT_2C. In addition, peripheral release of vasopressin involves serotonergic response which is partially mediated via 5-HT_2C.

Expression of the 5-HT_2C receptor in the CNS is modulated by female sex hormones estradiol and progesterone. Combination of the hormones decrease the receptor concentration in the ventral hippocampus in rats and could thus affect mood.^[25]

Genetics

Many human polymorphisms have been identified influencing the expression of 5-HT_2C. Significant correlations are suggested, specifically in relation to psychiatric disorders such as depression, OCD, and anxiety-related conditions. Polymorphisms also correlate with susceptibility to a number of conditions including substance use disorders and obesity. There are indications that the alternative splicing of the 5-HT_2C receptor is regulated by a snoRNA called SNORD115, the deletion of which is associated with Prader–Willi syndrome.^[26][27] As the human gene is located in the X chromosome, males have only one copy of the gene whereas women have two, meaning that mutations in the gene affect the phenotype of men even when the allele would be recessive in nature. As women have two copies of the gene, but only one allele is expressed in each cell, they are a mosaic for polymorphisms, meaning that one genetic variant may be prevalent in one tissue and another variant will be prevalent in a different tissue (as with all other x-linked genetic variations).

Ligands

Agonists

Main article: 5-HT2C receptor agonist

• A-372,159
• AL-38022A
• CP-809,101
• CPD-1^[28]
• Fenfluramine
• Lisuride
• Lorcaserin
• Mesulergine
• MK-212
• Naphthylisopropylamine
• Norfenfluramine
• Org 12,962
• ORG-37,684
• Oxaflozane
• PF-04479745^[29]
• PNU-22394
• PNU-181731
• Psychedelics
  • Lysergamides (LSD, etc.)
  • Phenethylamines (2C-B, DOI, DOM, Mescaline, etc.)
  • Piperazines (mCPP, TFMPP, etc.)
  • Tryptamines (5-MeO-DMT, Bufotenin, DMT, Psilocin, etc.)
• Ro60-0175
• Vabicaserin
• WAY-629
• WAY-161,503
• WAY-163,909
• WAY-261240
• YM-348
• CP-132,484 also 5HT2a agonist.

Partial agonists

• Aripiprazole

Antagonists

• Agomelatine
• CEPC^[30]
• Eltoprazine
• Etoperidone
• Flibanserin^[31]
• Fluoxetine
• FR-260,010
• Tedatioxetine
• Methysergide
• Mirtazapine
• Nefazodone
• Norfluoxetine
• O-Desmethyltramadol
• Promethazine
• RS-102,221
• SB-200,646
• SB-221,284
• SB-228,357
• SB-242,084
• SDZ SER-082
• Tramadol
• Trazodone

Inverse agonists

• Antidepressants ^{[citation needed]}
  • Tricyclics (Amitriptyline and Nortriptyline most notably)^[32]
  • Tetracyclics (Mirtazapine, Mianserin, Amoxapine, etc.)
• Antihistamines (Cyproheptadine, Hydroxyzine, Latrepirdine, etc.)
• Antipsychotics
  • Typicals (Chlorpromazine, Fluphenazine, Loxapine, Thioridazine, etc.)
  • Atypicals (Clozapine, Olanzapine, Quetiapine, Risperidone, Ziprasidone, etc.)
• Cinanserin
• Deramciclane
• Ketanserin
• LY-53,857
• Metergoline
• Methiothepin
• Pizotifen
• Ritanserin
• S-32212^[33]
• SB-206,553
• SB-228,357
• SB-243,213
• SB-242,084

Allosteric Modulators

Exogenous PAMs^[34] binding at the receptor vestibule

• CYD-1-79^[35]
• CTW-0415^[36]

Interactions

The 5-HT_2C receptor has been shown to interact with MPDZ.^[37][38]

RNA editing

5HT2CR pre-mRNA can be the subject of RNA editing.^[39] It is the only serotonin receptor as well as the only member of the large family of 7 transmembrane receptors (7TMRs) known to be edited. Different levels of editing result in a variety of effects on receptor function.

Type

The type of RNA editing that occurs in the pre-mRNA of the 5HT2CR is Adenosine to Inosine (A to I) editing.

A to I RNA editing is catalyzed by a family of adenosine deaminases acting on RNA (ADARs) that specifically recognize adenosines within double-stranded regions of pre-mRNAs and deaminate them to inosine. Inosines are recognised as guanosine by the cells translational machinery. There are three members of the ADAR family ADARs 1–3 with ADAR1 and ADAR2 being the only enzymatically active members. ADAR3 is thought to have a regulatory role in the brain. ADAR1 and ADAR2 are widely expressed in tissues while ADAR3 is restricted to the brain. The double stranded regions of RNA are formed by base-pairing between residues in the close to region of the editing site with residues usually in a neighboring intron but can be an exonic sequence. The region that base pairs with the editing region is known as an Editing Complementary Sequence (ECS).

ADARs bind interact directly with the dsRNA substrate via their double stranded RNA binding domains. If an editing site occurs within a coding sequence, it can result in a codon change. This can lead to translation of a protein isoform due to a change in its primary protein structure. Therefore, editing can also alter protein function. A to I editing occurs in a non coding RNA sequences such as introns, untranslated regions (UTRs), LINEs, SINEs ( especially Alu repeats) The function of A to I editing in these regions is thought to involve creation of splice sites and retention of RNAs in the nucleus amongst others.

Location

Editing occurs in 5 different closely located sites within exon 5, which corresponds to the second intracellular loop of the final protein. The sites are known as A, B, C′ (previously called E), C and D, and are predicted to occur within amino acid positions 156, 158 and 160. Several codon changes can occur due to A-to-I editing at these sites. Thirty-two different mRNA variants can occur leading to 24 different protein isoforms.

1. An Isoleucine to Valine (I/V) at amino acid position 157,161.
2. An Isoleucine to a Methionine(I/M) at amino acid position 157
3. An Aspartate to a Serine (N/S)at 159
4. An Aspartate to Asparagine(N/D) at 159
5. An Asparagine to a Glycine(N/G) at 159.

These codon changes which can occur due to A to I editing at these sites can lead to a maximum of 32 different mRNA variants leading to 24 different protein isoforms. The number of protein isoforms is less than 32 since some amino acids are encoded by more than one codon.^[40] Another editing site, site F has also been located in the exon complementary sequence (ECS) of intron 5.^[41] The ECS required for formation of double stranded RNA structure is found within intron 5.^[39]

Conservation

RNA editing of this receptor occurs at 4 locations in the rat.^[39] Editing also occurs in the mouse.^[42] The initial demonstration of RNA editing in rat.^[39] The predominant isoform in rat brain is VNV which differs from the most common type found in humans.^[39][43] The editing complementary sequence is known to be conserved across Mammalia.

Regulation

The 5-HT_2c receptor is the only serotonin receptor edited despite its close sequence similarities to other family members.^[43] 5HT2CR is different due to possessing an imperfect inverted repeat at the end of exon 5 and the beginning of intron 5 allowing formation of an RNA duplex producing the dsRNA required by ADARs for editing. Disruption of this inverted repeat was demonstrated to cease all editing.^[39] The different 5HT2CR mRNA isoforms are expressed differently throughout the brain, yet not all of the 24 have been detected perhaps due to tissue specific expression or low frequency editing of a particular type. Those isoforms that are not expressed at all or at a very low frequency are linked by being edited only at site C' and/or site B but not at site A. Some examples of differences in frequency of editing and site edited in different parts of the human brain of 5HT2CR include low frequency of editing in cerebellum and nearly all editing is at site D while in the hippocampus editing frequency is higher with site A being the main editing site. Site C' is only found edited in the thalamus. The most common isoform in human brain is the VSV isoform.^[40][43][44]

Mice knock out and other studies have been used to determine which ADAR enzyme are involved in editing. Editing at A and B sites has been demonstrated to be due to ADAR1 editing.^[45][46][47] Also since ADAR1 expression is increased in response to the presence of interferon α, it was also observed that editing at A and B sites was also increased because of this.^[45] C' and D sites require ADAR2 and editing is decreased by the presence of ADAR1 with editing of C' site only observed in ADAR1 double knock out mice.^[48] The C site has been shown to be mainly edited by ADAR2 but in presence of upregulated expression of ADAR1, there was an increase in editing of this site and the enzymes presence can also result in limited editing in ADAR 2 knock out mice.^[45][48] This demonstrates that there must be some form interaction between the two A to I editing enzymes. Also such interactions and tissue specific expression of ADARs interaction may explain the variety in editing patterns in different regions of the brain.

Consequences

Second, the editing pattern controls the amount of the 5-HT2CR mRNA that leads to the expression of full-length protein through the modulation of alternative splice site selection 76,77. Among three alternative splice donor sites (GU1 to GU3; Fig. 4C), GU2 is the only site that forms the mature mRNA to produce the functional, full-length 5-HT2CR protein. Unedited pre-mRNAs tend to be spliced at the GU1 site, resulting in the truncated, non-functional protein if translated 76,77. However, most pre-mRNAs edited at more than one position are spliced at GU2 77. Thus, when editing is inefficient, increased splicing at GU1 may act as a control mechanism to decrease biosynthesis of the 5-HT2CR-INI and thereby limit serotonin response. Third, RNA editing controls the ultimate physiological output of constitutively active receptors by affecting the cell surface expression of the 5-HT2CR. The 5-HT2CR-VGV, which displays the lowest level of constitutive activity, is fully expressed at the cell surface under basal conditions and is rapidly internalized in the presence of agonist 78; additionally, in vitro, LSD shows negligible activity with this isoform.^[49] In contrast, the 5-HT2CR-INI is constitutively internalized and accumulates in endosomes 78.

Structure

As mentioned editing results in several codon changes. The editing sites are found in the second intracellular domain of the protein which is also the receptors G protein coupling domain. Therefore, editing of these sites can affect the affinity of the receptor for G protein binding.^[39]

Function

Editing results in reduced affinity for specific G proteins which in turn affects internal signalling via second messengers (Phospholipase C signalling system). The fully edited isoform, VGV, considerably reduces 5-HT potency, G-protein coupling and agonist binding, compared to the unedited protein isoform, INI. 72–76. Most evidence for the effect of editing on function comes from downstream measurements of receptor activity, radio ligand binding and functional studies. Inhibitory effects are linked to the extent of editing. Those isoforms with a higher level of editing require higher levels of serotonin to activate the phospholipase c pathway. Unedited INI form has a greater tendency to isomerise to an active form which can more easily interact with G proteins. This indicates that RNA editing here may be a mechanism for regulating neuronal excitability by stabilising receptor signalling.^[39][43]

Editing is also thought to function in cell surface expression of the receptor subtype. The fully edited VGV, which has the lowest level of constitutive activity, is fully expressed at the cell surface while the non-edited INI is internalised and accumulates in endosome.^[50]

Editing is also thought to influence splicing. Three different spliced isoforms of the receptor exist. Editing regulates the amount of 5HT2CR mRNA which leads to translation of the full length protein selection of alternative splice sites. t76,77. These splice sites are termed Gu1, Gu2, GU3. Only GU2 site splicing results in translation of the full length receptor while editing at GU1 is known to result in translation of a truncated protein. This is thought to be a regulatory mechanism to decrease the amount of unedited isoform INI to limit serotonin response when editing is inefficient. Most of the pre-mRNAs which are edited are spliced at the GU2 site.^[41][44]

Dysregulation

Serotonin family of receptors are often linked to pathology of several human mental conditions such as Schizophrenia, anxiety, Bipolar disorder and major depression.^[51] There have been several experimental investigations into the effects of alternative editing patterns of the 5HT2CR and these conditions with a wide variability in results especially those relating to schizophrenia.^[52] Some studies have noted that there is an increase in RNA editing at site A in depressed suicide victims.^[12][52] E site editing was observed to be increased in individuals with major depression.^[53] In rat models this increase is also observed and can be reversed with fluoxetine with some suggestion that E site editing maybe linked to major depression.^[54][55]

See also

• 5-HT receptor
• 5-HT₂ receptor
• Anxiety/Aggression-Driven Depression
• Norepinephrine-dopamine disinhibitor

References

1. GRCm38: Ensembl release 89: ENSMUSG00000041380 – Ensembl, May 2017
2. "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
3. "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
4. "Entrez Gene: HTR2C 5-hydroxytryptamine (serotonin) receptor 2C".
5. Stam NJ, Vanderheyden P, van Alebeek C, Klomp J, de Boer T, van Delft AM, Olijve W (November 1994). "Genomic organisation and functional expression of the gene encoding the human serotonin 5-HT2C receptor". European Journal of Pharmacology. 269 (3): 339–348. doi:10.1016/0922-4106(94)90042-6. PMID 7895773.
6. Herrick-Davis K, Grinde E, Lindsley T, Cowan A, Mazurkiewicz JE (July 2012). "Oligomer size of the serotonin 5-hydroxytryptamine 2C (5-HT2C) receptor revealed by fluorescence correlation spectroscopy with photon counting histogram analysis: evidence for homodimers without monomers or tetramers". The Journal of Biological Chemistry. 287 (28): 23604–23614. doi:10.1074/jbc.M112.350249. PMC 3390635. PMID 22593582.
7. Peng Y, McCorvy JD, Harpsøe K, Lansu K, Yuan S, Popov P, et al. (February 2018). "5-HT_2C Receptor Structures Reveal the Structural Basis of GPCR Polypharmacology". Cell. 172 (4): 719–730.e14. doi:10.1016/j.cell.2018.01.001. PMC 6309861. PMID 29398112.
8. Abramowski D, Rigo M, Duc D, Hoyer D, Staufenbiel M (December 1995). "Localization of the 5-hydroxytryptamine2C receptor protein in human and rat brain using specific antisera". Neuropharmacology. 34 (12): 1635–1645. doi:10.1016/0028-3908(95)00138-7. PMID 8788961. S2CID 45542707.
9. Hoffman BJ, Mezey E (April 1989). "Distribution of serotonin 5-HT1C receptor mRNA in adult rat brain". FEBS Letters. 247 (2): 453–462. doi:10.1016/0014-5793(89)81390-0. PMID 2714444. S2CID 23825490.
10. Alex KD, Yavanian GJ, McFarlane HG, Pluto CP, Pehek EA (March 2005). "Modulation of dopamine release by striatal 5-HT2C receptors". Synapse. 55 (4): 242–251. doi:10.1002/syn.20109. PMID 15668911. S2CID 11405860.
11. Heisler LK, Zhou L, Bajwa P, Hsu J, Tecott LH (July 2007). "Serotonin 5-HT(2C) receptors regulate anxiety-like behavior". Genes, Brain and Behavior. 6 (5): 491–496. doi:10.1111/j.1601-183X.2007.00316.x. PMID 17451451.
12. Niswender CM, Herrick-Davis K, Dilley GE, Meltzer HY, Overholser JC, Stockmeier CA, et al. (May 2001). "RNA editing of the human serotonin 5-HT2C receptor. alterations in suicide and implications for serotonergic pharmacotherapy". Neuropsychopharmacology. 24 (5): 478–491. doi:10.1016/S0893-133X(00)00223-2. PMID 11282248.
13. Guaiana G, Gupta S, Chiodo D, Davies SJ, Haederle K, Koesters M (December 2013). "Agomelatine versus other antidepressive agents for major depression". The Cochrane Database of Systematic Reviews (12): CD008851. doi:10.1002/14651858.CD008851.pub2. PMID 24343836.
14. Cipriani A, Furukawa TA, Salanti G, Chaimani A, Atkinson LZ, Ogawa Y, et al. (April 2018). "Comparative efficacy and acceptability of 21 antidepressant drugs for the acute treatment of adults with major depressive disorder: a systematic review and network meta-analysis". Lancet. 391 (10128): 1357–1366. doi:10.1016/S0140-6736(17)32802-7. PMC 5889788. PMID 29477251.
15. Ni YG, Miledi R (March 1997). "Blockage of 5HT2C serotonin receptors by fluoxetine (Prozac)". Proceedings of the National Academy of Sciences of the United States of America. 94 (5): 2036–2040. Bibcode:1997PNAS...94.2036N. doi:10.1073/pnas.94.5.2036. PMC 20038. PMID 9050900.
16. Berg KA, Harvey JA, Spampinato U, Clarke WP (December 2005). "Physiological relevance of constitutive activity of 5-HT2A and 5-HT2C receptors". Trends in Pharmacological Sciences. 26 (12): 625–630. doi:10.1016/j.tips.2005.10.008. PMID 16269190.
17. Roth BL, Driscol J. "PDSP K_i Database". Psychoactive Drug Screening Program (PDSP). University of North Carolina at Chapel Hill and the United States National Institute of Mental Health. Retrieved 14 August 2017.
18. Anttila SA, Leinonen EV (2001). "A review of the pharmacological and clinical profile of mirtazapine". CNS Drug Reviews. 7 (3): 249–264. doi:10.1111/j.1527-3458.2001.tb00198.x. PMC 6494141. PMID 11607047.
19. Frazer A (April 1997). "Pharmacology of antidepressants". Journal of Clinical Psychopharmacology. 17 (Suppl 1): 2S–18S. doi:10.1097/00004714-199704001-00002. PMID 9090573.
20. Del'Guidice T, Lemay F, Lemasson M, Levasseur-Moreau J, Manta S, Etievant A, et al. (April 2014). "Stimulation of 5-HT2C receptors improves cognitive deficits induced by human tryptophan hydroxylase 2 loss of function mutation". Neuropsychopharmacology. 39 (5): 1125–1134. doi:10.1038/npp.2013.313. PMC 3957106. PMID 24196946.
21. Esposito E (February 2006). "Serotonin-dopamine interaction as a focus of novel antidepressant drugs". Current Drug Targets. 7 (2): 177–185. doi:10.2174/138945006775515455. PMID 16475959.
22. Bubar MJ, Cunningham KA (2006). "Serotonin 5-HT2A and 5-HT2C receptors as potential targets for modulation of psychostimulant use and dependence". Current Topics in Medicinal Chemistry. 6 (18): 1971–1985. doi:10.2174/156802606778522131. PMID 17017968.
23. Jørgensen HS (November 2007). "Studies on the neuroendocrine role of serotonin". Danish Medical Bulletin. 54 (4): 266–288. PMID 18208678.
24. Heisler LK, Pronchuk N, Nonogaki K, Zhou L, Raber J, Tung L, et al. (June 2007). "Serotonin activates the hypothalamic-pituitary-adrenal axis via serotonin 2C receptor stimulation". The Journal of Neuroscience. 27 (26): 6956–6964. doi:10.1523/JNEUROSCI.2584-06.2007. PMC 6672238. PMID 17596444.
25. Birzniece V, Johansson IM, Wang MD, Bäckström T, Olsson T (February 2002). "Ovarian hormone effects on 5-hydroxytryptamine(2A) and 5-hydroxytryptamine(2C) receptor mRNA expression in the ventral hippocampus and frontal cortex of female rats". Neuroscience Letters. 319 (3): 157–161. doi:10.1016/S0304-3940(01)02570-8. PMID 11834317. S2CID 6902168.
26. Kishore S, Stamm S (January 2006). "The snoRNA HBII-52 regulates alternative splicing of the serotonin receptor 2C". Science. 311 (5758): 230–232. Bibcode:2006Sci...311..230K. doi:10.1126/science.1118265. PMID 16357227. S2CID 44527461.
27. Sahoo T, del Gaudio D, German JR, Shinawi M, Peters SU, Person RE, et al. (June 2008). "Prader-Willi phenotype caused by paternal deficiency for the HBII-85 C/D box small nucleolar RNA cluster". Nature Genetics. 40 (6): 719–721. doi:10.1038/ng.158. PMC 2705197. PMID 18500341.
28. Rodriguez MM, Overshiner C, Leander JD, Li X, Morrow D, Conway RG, et al. (2017). "Behavioral Effects of a Novel Benzofuranyl-Piperazine Serotonin-2C Receptor Agonist Suggest a Potential Therapeutic Application in the Treatment of Obsessive-Compulsive Disorder". Frontiers in Psychiatry. 8: 89. doi:10.3389/fpsyt.2017.00089. PMC 5438973. PMID 28588509.
29. Storer RI, Brennan PE, Brown AD, Bungay PJ, Conlon KM, Corbett MS, et al. (June 2014). "Multiparameter optimization in CNS drug discovery: design of pyrimido[4,5-d]azepines as potent 5-hydroxytryptamine 2C (5-HT₂C) receptor agonists with exquisite functional selectivity over 5-HT₂A and 5-HT₂B receptors". Journal of Medicinal Chemistry. 57 (12): 5258–5269. doi:10.1021/jm5003292. PMID 24878222.
30. McCorvy JD, Harland AA, Maglathlin R, Nichols DE (November 2011). "A 5-HT(2C) receptor antagonist potentiates a low dose amphetamine-induced conditioned place preference". Neuroscience Letters. 505 (1): 10–13. doi:10.1016/j.neulet.2011.07.036. PMC 3213641. PMID 21827831.
31. Stahl SM, Sommer B, Allers KA (January 2011). "Multifunctional pharmacology of flibanserin: possible mechanism of therapeutic action in hypoactive sexual desire disorder". The Journal of Sexual Medicine. 8 (1): 15–27. doi:10.1111/j.1743-6109.2010.02032.x. PMID 20840530.
32. Roth BL, Driscol J. "PDSP K_i Database". Psychoactive Drug Screening Program (PDSP). University of North Carolina at Chapel Hill and the United States National Institute of Mental Health. Retrieved 14 August 2017.
33. Dekeyne A, Brocco M, Loiseau F, Gobert A, Rivet JM, Di Cara B, et al. (March 2012). "S32212, a novel serotonin type 2C receptor inverse agonist/α2-adrenoceptor antagonist and potential antidepressant: II. A behavioral, neurochemical, and electrophysiological characterization". The Journal of Pharmacology and Experimental Therapeutics. 340 (3): 765–780. doi:10.1124/jpet.111.187534. PMID 22178753. S2CID 11363664.
34. De Deurwaerdère P, Chagraoui A, Cunningham KA (2020). "Editorial: Contemporary Perspective on 5-HT_2C Receptor Function and Its Pharmacological Targeting". Frontiers in Pharmacology. 11: 606414. doi:10.3389/fphar.2020.606414. PMC 7724505. PMID 33324228.
35. Wild CT, Miszkiel JM, Wold EA, Soto CA, Ding C, Hartley RM, et al. (January 2019). "Design, Synthesis, and Characterization of 4-Undecylpiperidine-2-carboxamides as Positive Allosteric Modulators of the Serotonin (5-HT) 5-HT_2C Receptor". Journal of Medicinal Chemistry. 62 (1): 288–305. doi:10.1021/acs.jmedchem.8b00401. PMC 6533912. PMID 29620897.
36. Wold EA, Garcia EJ, Wild CT, Miszkiel JM, Soto CA, Chen J, et al. (July 2020). "Discovery of 4-Phenylpiperidine-2-Carboxamide Analogues as Serotonin 5-HT_2C Receptor-Positive Allosteric Modulators with Enhanced Drug-like Properties". Journal of Medicinal Chemistry. 63 (14): 7529–7544. doi:10.1021/acs.jmedchem.9b01953. PMC 8434884. PMID 32567857.
37. Becamel C, Figge A, Poliak S, Dumuis A, Peles E, Bockaert J, et al. (April 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): 12974–12982. doi:10.1074/jbc.M008089200. PMID 11150294.
38. Ullmer C, Schmuck K, Figge A, Lübbert H (March 1998). "Cloning and characterization of MUPP1, a novel PDZ domain protein". FEBS Letters. 424 (1–2): 63–68. doi:10.1016/S0014-5793(98)00141-0. PMID 9537516.
39. Burns CM, Chu H, Rueter SM, Hutchinson LK, Canton H, Sanders-Bush E, Emeson RB (May 1997). "Regulation of serotonin-2C receptor G-protein coupling by RNA editing". Nature. 387 (6630): 303–308. Bibcode:1997Natur.387..303B. doi:10.1038/387303a0. PMID 9153397. S2CID 4247011.
40. Fitzgerald LW, Iyer G, Conklin DS, Krause CM, Marshall A, Patterson JP, et al. (August 1999). "Messenger RNA editing of the human serotonin 5-HT2C receptor". Neuropsychopharmacology. 21 (2 Suppl): 82S–90S. doi:10.1016/S0893-133X(99)00004-4. PMID 10432493.
41. Flomen R, Knight J, Sham P, Kerwin R, Makoff A (2004). "Evidence that RNA editing modulates splice site selection in the 5-HT2C receptor gene". Nucleic Acids Research. 32 (7): 2113–2122. doi:10.1093/nar/gkh536. PMC 407821. PMID 15087490.
42. Hackler EA, Airey DC, Shannon CC, Sodhi MS, Sanders-Bush E (May 2006). "5-HT(2C) receptor RNA editing in the amygdala of C57BL/6J, DBA/2J, and BALB/cJ mice". Neuroscience Research. 55 (1): 96–104. doi:10.1016/j.neures.2006.02.005. PMID 16580757. S2CID 3799598.
43. Niswender CM, Copeland SC, Herrick-Davis K, Emeson RB, Sanders-Bush E (April 1999). "RNA editing of the human serotonin 5-hydroxytryptamine 2C receptor silences constitutive activity". The Journal of Biological Chemistry. 274 (14): 9472–9478. doi:10.1074/jbc.274.14.9472. PMID 10092629.
44. Wang Q, O'Brien PJ, Chen CX, Cho DS, Murray JM, Nishikura K (March 2000). "Altered G protein-coupling functions of RNA editing isoform and splicing variant serotonin2C receptors". Journal of Neurochemistry. 74 (3): 1290–1300. doi:10.1046/j.1471-4159.2000.741290.x. PMID 10693963.
45. Yang W, Wang Q, Kanes SJ, Murray JM, Nishikura K (April 2004). "Altered RNA editing of serotonin 5-HT2C receptor induced by interferon: implications for depression associated with cytokine therapy". Brain Research. Molecular Brain Research. 124 (1): 70–78. doi:10.1016/j.molbrainres.2004.02.010. PMID 15093687.
46. Sukma M, Tohda M, Watanabe H, Matsumoto K (August 2005). "The mRNA expression differences of RNA editing enzymes in differentiated and undifferentiated NG108-15 cells". Journal of Pharmacological Sciences. 98 (4): 467–470. doi:10.1254/jphs.SC0050074. PMID 16082172.
47. Tohda M, Sukma M, Watanabe H (October 2004). "RNA editing and short variant of serotonin 2C receptor mRNA in neuronally differentiated NG108-15 cells". Journal of Pharmacological Sciences. 96 (2): 164–169. doi:10.1254/jphs.FP0040227. PMID 15492466.
48. Hartner JC, Schmittwolf C, Kispert A, Müller AM, Higuchi M, Seeburg PH (February 2004). "Liver disintegration in the mouse embryo caused by deficiency in the RNA-editing enzyme ADAR1". The Journal of Biological Chemistry. 279 (6): 4894–4902. doi:10.1074/jbc.M311347200. PMID 14615479.
49. Backstrom JR, Chang MS, Chu H, Niswender CM, Sanders-Bush E (August 1999). "Agonist-directed signaling of serotonin 5-HT2C receptors: differences between serotonin and lysergic acid diethylamide (LSD)". Neuropsychopharmacology. 21 (2 Suppl): 77S–81S. doi:10.1016/S0893-133X(99)00005-6. PMID 10432492. S2CID 25007217.
50. Marion S, Weiner DM, Caron MG (January 2004). "RNA editing induces variation in desensitization and trafficking of 5-hydroxytryptamine 2c receptor isoforms". The Journal of Biological Chemistry. 279 (4): 2945–2954. doi:10.1074/jbc.M308742200. PMID 14602721.
51. Baxter G, Kennett G, Blaney F, Blackburn T (March 1995). "5-HT2 receptor subtypes: a family re-united?". Trends in Pharmacological Sciences. 16 (3): 105–110. doi:10.1016/S0165-6147(00)88991-9. PMID 7792930.
52. Iwamoto K, Kato T (August 2003). "RNA editing of serotonin 2C receptor in human postmortem brains of major mental disorders". Neuroscience Letters. 346 (3): 169–172. doi:10.1016/S0304-3940(03)00608-6. PMID 12853111. S2CID 24977282.
53. Gurevich I, Tamir H, Arango V, Dwork AJ, Mann JJ, Schmauss C (April 2002). "Altered editing of serotonin 2C receptor pre-mRNA in the prefrontal cortex of depressed suicide victims". Neuron. 34 (3): 349–356. doi:10.1016/S0896-6273(02)00660-8. PMID 11988167.
54. Iwamoto K, Nakatani N, Bundo M, Yoshikawa T, Kato T (September 2005). "Altered RNA editing of serotonin 2C receptor in a rat model of depression". Neuroscience Research. 53 (1): 69–76. doi:10.1016/j.neures.2005.06.001. PMID 16005997. S2CID 25363004.
55. Gurevich I, Englander MT, Adlersberg M, Siegal NB, Schmauss C (December 2002). "Modulation of serotonin 2C receptor editing by sustained changes in serotonergic neurotransmission". The Journal of Neuroscience. 22 (24): 10529–10532. doi:10.1523/JNEUROSCI.22-24-10529.2002. PMC 6758441. PMID 12486144.

External links

• Human HTR2C genome location and HTR2C gene details page in the UCSC Genome Browser.
• Overview of all the structural information available in the PDB for UniProt: P28335 (5-hydroxytryptamine receptor 2C) at the PDBe-KB.

Further reading

• Niswender CM, Sanders-Bush E, Emeson RB (December 1998). "Identification and characterization of RNA editing events within the 5-HT2C receptor". Annals of the New York Academy of Sciences. 861 (1): 38–48. Bibcode:1998NYASA.861...38N. doi:10.1111/j.1749-6632.1998.tb10171.x. PMID 9928237. S2CID 25127011.
• Hoyer D, Hannon JP, Martin GR (April 2002). "Molecular, pharmacological and functional diversity of 5-HT receptors". Pharmacology, Biochemistry, and Behavior. 71 (4): 533–554. doi:10.1016/S0091-3057(01)00746-8. PMID 11888546. S2CID 25543069.
• 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.
• Van Oekelen D, Luyten WH, Leysen JE (April 2003). "5-HT2A and 5-HT2C receptors and their atypical regulation properties". Life Sciences. 72 (22): 2429–2449. doi:10.1016/S0024-3205(03)00141-3. PMID 12650852.
• Reynolds GP, Templeman LA, Zhang ZJ (July 2005). "The role of 5-HT2C receptor polymorphisms in the pharmacogenetics of antipsychotic drug treatment". Progress in Neuro-Psychopharmacology & Biological Psychiatry. 29 (6): 1021–1028. doi:10.1016/j.pnpbp.2005.03.019. PMID 15953671. S2CID 30964513.
• Millan MJ (2006). "Serotonin 5-HT2C receptors as a target for the treatment of depressive and anxious states: focus on novel therapeutic strategies". Therapie. 60 (5): 441–460. doi:10.2515/therapie:2005065. PMID 16433010.
• Milatovich A, Hsieh CL, Bonaminio G, Tecott L, Julius D, Francke U (December 1992). "Serotonin receptor 1c gene assigned to X chromosome in human (band q24) and mouse (bands D-F4)". Human Molecular Genetics. 1 (9): 681–684. doi:10.1093/hmg/1.9.681. PMID 1302605.
• Saltzman AG, Morse B, Whitman MM, Ivanshchenko Y, Jaye M, Felder S (December 1991). "Cloning of the human serotonin 5-HT2 and 5-HT1C receptor subtypes". Biochemical and Biophysical Research Communications. 181 (3): 1469–1478. doi:10.1016/0006-291X(91)92105-S. PMID 1722404.
• Lappalainen J, Zhang L, Dean M, Oz M, Ozaki N, Yu DH, et al. (May 1995). "Identification, expression, and pharmacology of a Cys23-Ser23 substitution in the human 5-HT2c receptor gene (HTR2C)". Genomics. 27 (2): 274–279. doi:10.1006/geno.1995.1042. PMID 7557992.
• Tecott LH, Sun LM, Akana SF, Strack AM, Lowenstein DH, Dallman MF, Julius D (April 1995). "Eating disorder and epilepsy in mice lacking 5-HT2c serotonin receptors". Nature. 374 (6522): 542–546. Bibcode:1995Natur.374..542T. doi:10.1038/374542a0. PMID 7700379. S2CID 4368727.
• Stam NJ, Vanderheyden P, van Alebeek C, Klomp J, de Boer T, van Delft AM, Olijve W (November 1994). "Genomic organisation and functional expression of the gene encoding the human serotonin 5-HT2C receptor". European Journal of Pharmacology. 269 (3): 339–348. doi:10.1016/0922-4106(94)90042-6. PMID 7895773.
• Xie E, Zhu L, Zhao L, Chang LS (August 1996). "The human serotonin 5-HT2C receptor: complete cDNA, genomic structure, and alternatively spliced variant". Genomics. 35 (3): 551–561. doi:10.1006/geno.1996.0397. PMID 8812491.
• Burns CM, Chu H, Rueter SM, Hutchinson LK, Canton H, Sanders-Bush E, Emeson RB (May 1997). "Regulation of serotonin-2C receptor G-protein coupling by RNA editing". Nature. 387 (6630): 303–308. Bibcode:1997Natur.387..303B. doi:10.1038/387303a0. PMID 9153397. S2CID 4247011.
• Brennan TJ, Seeley WW, Kilgard M, Schreiner CE, Tecott LH (August 1997). "Sound-induced seizures in serotonin 5-HT2c receptor mutant mice". Nature Genetics. 16 (4): 387–390. doi:10.1038/ng0897-387. PMID 9241279. S2CID 21333874.
• Ullmer C, Schmuck K, Figge A, Lübbert H (March 1998). "Cloning and characterization of MUPP1, a novel PDZ domain protein". FEBS Letters. 424 (1–2): 63–68. doi:10.1016/S0014-5793(98)00141-0. PMID 9537516.
• Samochowiec J, Smolka M, Winterer G, Rommelspacher H, Schmidt LG, Sander T (April 1999). "Association analysis between a Cys23Ser substitution polymorphism of the human 5-HT2c receptor gene and neuronal hyperexcitability". American Journal of Medical Genetics. 88 (2): 126–130. doi:10.1002/(SICI)1096-8628(19990416)88:2<126::AID-AJMG6>3.0.CO;2-M. PMID 10206230.
• Cargill M, Altshuler D, Ireland J, Sklar P, Ardlie K, Patil N, et al. (July 1999). "Characterization of single-nucleotide polymorphisms in coding regions of human genes". Nature Genetics. 22 (3): 231–238. doi:10.1038/10290. PMID 10391209. S2CID 195213008.
• Marshall SE, Bird TG, Hart K, Welsh KI (December 1999). "Unified approach to the analysis of genetic variation in serotonergic pathways". American Journal of Medical Genetics. 88 (6): 621–627. doi:10.1002/(SICI)1096-8628(19991215)88:6<621::AID-AJMG9>3.0.CO;2-H. PMID 10581480.
• Backstrom JR, Price RD, Reasoner DT, Sanders-Bush E (August 2000). "Deletion of the serotonin 5-HT2C receptor PDZ recognition motif prevents receptor phosphorylation and delays resensitization of receptor responses". The Journal of Biological Chemistry. 275 (31): 23620–23626. doi:10.1074/jbc.M000922200. PMID 10816555.

This article incorporates text from the United States National Library of Medicine, which is in the public domain.