View source for Oxytocin receptor

{{Short description|Genes on human chromosome 3}}
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{{Infobox_gene}}
The '''oxytocin receptor''', also known as '''OXTR''', is a [[protein]] which functions as [[receptor (biochemistry)|receptor]] for the [[hormone]] and [[neurotransmitter]] [[oxytocin]].<ref name="pmid11274341">{{cite journal | vauthors = Gimpl G, Fahrenholz F | title = The oxytocin receptor system: structure, function, and regulation | journal = Physiological Reviews | volume = 81 | issue = 2 | pages = 629–83 | date = April 2001 | pmid = 11274341 | doi = 10.1152/physrev.2001.81.2.629| s2cid = 13265083 }}</ref><ref name="pmid12826328">{{cite journal | vauthors = Zingg HH, Laporte SA | title = The oxytocin receptor | journal = Trends in Endocrinology and Metabolism | volume = 14 | issue = 5 | pages = 222–7 | date = July 2003 | pmid = 12826328 | doi = 10.1016/S1043-2760(03)00080-8 | s2cid = 21540056 }}</ref> In humans, the oxytocin receptor is encoded by the ''OXTR'' [[gene]]<ref name="NCBI Gene">{{EntrezGene|5021}}</ref><ref name="pmid1313946">{{cite journal | vauthors = Kimura T, Tanizawa O, Mori K, Brownstein MJ, Okayama H | title = Structure and expression of a human oxytocin receptor | journal = Nature | volume = 356 | issue = 6369 | pages = 526–9 | date = April 1992 | pmid = 1313946 | doi = 10.1038/356526a0 | bibcode = 1992Natur.356..526K | s2cid = 4273722 | url = http://ir.library.osaka-u.ac.jp/dspace/bitstream/11094/38708/1/10817_%e8%a6%81%e6%97%a8.pdf | access-date = 2021-05-29 | archive-date = 2017-09-21 | archive-url = https://web.archive.org/web/20170921222638/http://ir.library.osaka-u.ac.jp/dspace/bitstream/11094/38708/1/10817_%e8%a6%81%e6%97%a8.pdf | url-status = dead }}</ref> which has been localized to human [[chromosome 3|chromosome 3p25]].<ref name="pmid7607693">{{cite journal | vauthors = Simmons CF, Clancy TE, Quan R, Knoll JH | title = The oxytocin receptor gene (OXTR) localizes to human chromosome 3p25 by fluorescence in situ hybridization and PCR analysis of somatic cell hybrids | journal = Genomics | volume = 26 | issue = 3 | pages = 623–5 | date = April 1995 | pmid = 7607693 | doi = 10.1016/0888-7543(95)80188-R }}</ref>

[[File:OTR evolutionary tree.gif|thumb|400px|right|Evolutionary tree of the oxytocin, [[vasotocin]], [[mesotocin]] and [[isotocin]] receptors and their ligands. From Koechbach et al.<ref name="koechbach2013">{{cite journal | vauthors = Koehbach J, Stockner T, Bergmayr C, Muttenthaler M, Gruber CW | title = Insights into the molecular evolution of oxytocin receptor ligand binding | journal = Biochemical Society Transactions | volume = 41 | issue = 1 | pages = 197–204 | date = February 2013 | pmid = 23356283 | pmc = 3634130 | doi = 10.1042/BST20120256 }}</ref>]]

==Function and location==

The OXTR protein belongs to the [[G protein-coupled receptor|G-protein coupled receptor]] family, specifically [[Gq alpha subunit|G<sub>q</sub>]],<ref name="pmid11274341"/> and acts as a receptor for oxytocin. Its activity is mediated by [[G protein]]s that activate several different [[second messenger]] systems.<ref>{{cite book | vauthors = Devost D, Wrzal P, Zingg HH | chapter = Oxytocin receptor signalling | volume = 170 | pages = 167–76 | year = 2008 | pmid = 18655881 | doi = 10.1016/S0079-6123(08)00415-9 | isbn = 978-0-444-53201-5 | series = Progress in Brain Research | title = Advances in Vasopressin and Oxytocin — from Genes to Behaviour to Disease }}</ref><ref>{{cite book | vauthors = Gimpl G, Reitz J, Brauer S, Trossen C | chapter = Oxytocin receptors: ligand binding, signalling and cholesterol dependence | volume = 170 | pages = 193–204 | year = 2008 | pmid = 18655883 | doi = 10.1016/S0079-6123(08)00417-2 | isbn = 978-0-444-53201-5 | series = Progress in Brain Research | title = Advances in Vasopressin and Oxytocin — from Genes to Behaviour to Disease }}</ref>

Oxytocin receptors are expressed by the [[myoepithelial cell]]s of the [[mammary gland]], and in both the [[myometrium]] and [[endometrium]] of the [[uterus]] at the end of [[pregnancy]].
The oxytocin-oxytocin receptor system plays an important role as an inducer of uterine contractions during [[parturition]] and of milk ejection.

OXTR is also associated with the central nervous system. The gene is believed to play a major role in social, cognitive, and emotional behavior.<ref name="Maud et al 2018">{{cite journal | vauthors = Maud C, Ryan J, McIntosh JE, Olsson CA | title = The role of oxytocin receptor gene (OXTR) DNA methylation (DNAm) in human social and emotional functioning: a systematic narrative review | journal = BMC Psychiatry | volume = 18 | issue = 1 | pages = 154 | date = May 2018 | pmid = 29843655 | pmc = 5975530 | doi = 10.1186/s12888-018-1740-9 | doi-access = free }}</ref>  A decrease in OXTR expression by methylation of the ''OXTR'' gene is associated with [[callous and unemotional traits]] in adolescence, rigid thinking in [[anorexia nervosa]], problems with facial and emotional recognition, and difficulties in the [[regulation of affect|affect regulation]]. A reduction in this gene is believed to lead to prenatal stress, postnatal depression, and social anxiety.<ref name="Maud et al 2018"/> Further research must be gathered before concluding these findings, however strong evidence is pointing in this direction. Studies on ''OXTR'' methylation—which downregulates oxytocin mechanisms—suggest this process is associated with increased gray matter density in the amygdala, implicating ''OXTR'' regulation in stress and parasympathetic regulation.<ref>{{cite journal | vauthors = Lancaster K, Goldbeck L, Puglia MH, Morris JP, Connelly JJ | title = DNA methylation of OXTR is associated with parasympathetic nervous system activity and amygdala morphology | journal = Social Cognitive and Affective Neuroscience | volume = 13 | issue = 11 | pages = 1155–1162 | date = November 2018 | pmid = 30257007 | pmc = 6234329 | doi = 10.1093/scan/nsy086 }}</ref>

In some mammals, oxytocin receptors are also found in the [[kidney]] and [[heart]].

===Mesolimbic dopamine pathways===
The oxytocinergic circuit projecting from the [[paraventricular hypothalamic nucleus]] (PVN) innervates the [[ventral tegmental area]] (VTA) dopaminergic neurons that project to the [[nucleus accumbens]], i.e., the [[mesolimbic pathway]].<ref name="Oxytocinergic circuit" />  Activation of the PVN→VTA projection by oxytocin affects sexual, social, and addictive behavior via this link to the mesolimbic pathway;<ref name="Oxytocinergic circuit">{{cite journal | vauthors = McGregor IS, Callaghan PD, Hunt GE | title = From ultrasocial to antisocial: a role for oxytocin in the acute reinforcing effects and long-term adverse consequences of drug use? | journal = British Journal of Pharmacology | volume = 154 | issue = 2 | pages = 358–68 | date = May 2008 | pmid = 18475254 | pmc = 2442436 | doi = 10.1038/bjp.2008.132 | quote = Recent studies also highlight remarkable anxiolytic and prosocial effects of intranasally administered OT in humans, including increased ‘trust’, decreased amygdala activation towards fear-inducing stimuli, improved recognition of social cues and increased gaze directed towards the eye regions of others (Kirsch et al., 2005; Kosfeld et al., 2005; Domes et al., 2006; Guastella et al., 2008). }}</ref> specifically, oxytocin exerts a prosexual and prosocial effect in this region.<ref name="Oxytocinergic circuit" />

== Polymorphism ==

The receptors for oxytocin (OXTR) have genetic differences with varied effects on individual behavior.  The [[polymorphism (biology)|polymorphism]] (rs53576) occurs on the third [[intron]] of OXTR in three types: GG, AG, AA. The GG allele is connected with oxytocin levels in people {{Citation needed|date=October 2018|reason=Reliable source needed for the whole sentence}}. A-allele carrier individuals are associated with more sensitivity to stress, fewer social skills, and more mental health issues than the GG-carriers.<ref name="Saphire-Bernstein_2011">{{cite journal | vauthors = Saphire-Bernstein S, Way BM, Kim HS, Sherman DK, Taylor SE | title = Oxytocin receptor gene (OXTR) is related to psychological resources | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 108 | issue = 37 | pages = 15118–22 | date = September 2011 | pmid = 21896752 | pmc = 3174632 | doi = 10.1073/pnas.1113137108 | bibcode = 2011PNAS..10815118S | doi-access = free }}</ref>{{Qualify evidence}}

In a study looking at [[empathy]] and [[stress (biology)|stress]], individuals with the allele GG scored higher than A-carrier individuals in a "Reading the Mind in the Eyes" test.  GG carriers, with their naturally higher levels of oxytocin, were better able to distinguish between emotions.{{Citation needed|date=October 2018|reason=Reliable source needed for both sentences}}  A-allele carriers responded with more stress to stressful situations than GG-allele carriers.<ref name="pmid19934046">{{cite journal | vauthors = Rodrigues SM, Saslow LR, Garcia N, John OP, Keltner D | title = Oxytocin receptor genetic variation relates to empathy and stress reactivity in humans | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 106 | issue = 50 | pages = 21437–41 | date = December 2009 | pmid = 19934046 | pmc = 2795557 | doi = 10.1073/pnas.0909579106 | bibcode = 2009PNAS..10621437R | doi-access = free }}</ref>{{Explain|date=March 2021}} A-allele carriers had lower scores on psychological resources, like optimism, mastery, and self-esteem, than GG individuals when measured with factor analysis for depressive symptomology and psychological resources, along with the [[Beck Depression Inventory]]. A-allele carriers had higher depressive symptomology and lower psychological resources than GG individuals.<ref name="Saphire-Bernstein_2011"/>{{Qualify evidence}} A-allele individuals scored lower in human sociality than GG people on a [[Tridimensional Personality Questionnaire]].  AA individuals had the lowest amygdala activation while processing emotionally salient information and those with GG had the highest activity when tested using BOLD during an [[fMRI]].<ref name="pmid20647384">{{cite journal | vauthors = Tost H, Kolachana B, Hakimi S, Lemaitre H, Verchinski BA, Mattay VS, Weinberger DR, Meyer-Lindenberg A | title = A common allele in the oxytocin receptor gene (OXTR) impacts prosocial temperament and human hypothalamic-limbic structure and function | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 107 | issue = 31 | pages = 13936–41 | date = August 2010 | pmid = 20647384 | pmc = 2922278 | doi = 10.1073/pnas.1003296107 | bibcode = 2010PNAS..10713936T | doi-access = free }}</ref> On the other hand, variations at the CD38 rs3796863 and OXTR rs53576 loci were not associated with psychosocial characteristics of adolescents assessed with the [[Strengths and Difficulties Questionnaire (SDQ)]]; in studies with a similar design, authors recommend replication with larger samples and greater power to detect small effects, especially in age–sex subgroups of adolescents.<ref>{{cite journal | vauthors = Tereshchenko S, Kasparov E, Zobova S, Smolnikova M, Evert L, Semenova N, Zaitseva O, Shubina M, Gorbacheva N, Lapteva L | title = Oxytocin Pathway Gene (''CD38, OXTR'') Variants Are Not Related to Psychosocial Characteristics Defined by Strengths and Difficulties Questionnaire in Adolescents: A Field School-Based Study | journal = Frontiers in Psychiatry | volume = 12 | pages = 714093 | date = 2021 | pmid = 34434131 | doi = 10.3389/fpsyt.2021.714093 |pmc=8380924  | doi-access = free }}</ref>

The frequency of the A allele varies among ethnic groups, being significantly more common among East Asians than Europeans.<ref name=Sasaki_2011>{{cite journal |vauthors=Sasaki JY, Kim HS, Xu J | title = Religion and Well-being: The Moderating Role of Culture and the Oxytocin Receptor (OXTR) Gene | journal = Journal of Cross-Cultural Psychology |date=July 2011 | volume = 42 | issue = 8 | pages = 1394–1405 | doi = 10.1177/0022022111412526 | s2cid = 145567198 | url = https://labs.psych.ucsb.edu/kim/heejung/sasakikimxu.pdf }}</ref>{{Quantify|date=March 2021}}{{Additional citation needed|date=March 2021}}

Some evidence suggests an association between OXTR gene polymorphism, [[IQ]], and [[autism spectrum disorder]] (ASD).<ref>Lerer, E., Levi, S., Salomon, S. et al. Association between the oxytocin receptor (OXTR) gene and autism: relationship to Vineland Adaptive Behavior Scales and cognition. Mol Psychiatry 13, 980–988 (2008). https://doi.org/10.1038/sj.mp.4002087</ref> Studies have done research focusing on variants in the third intron of the gene, a region that is strongly correlated with personality traits and ASD. OXTR knockout mice have shown abnormal behaviors such as social impairments and aggressiveness. These abnormalities can be reduced with oxytocin or oxytocin agonist administration. Overall, the study suggests that rare variants are considerably more abundant in individuals with ASD compared to that of a normal individual, however further research with larger sample sizes must be completed before concluding any information.<ref>{{cite journal | vauthors = de Oliveira Pereira Ribeiro L, Vargas-Pinilla P, Kappel DB, Longo D, Ranzan J, Becker MM, Dos Santos Riesgo R, Schuler-Faccini L, Roman T, Schuch JB | title = Evidence for Association Between OXTR Gene and ASD Clinical Phenotypes | journal = Journal of Molecular Neuroscience | volume = 65 | issue = 2 | pages = 213–221 | date = June 2018 | pmid = 29858823 | doi = 10.1007/s12031-018-1088-0 | s2cid = 46924606 }}</ref>

== Ligands ==

Several selective [[ligand]]s for the oxytocin receptor have recently been developed, but close similarity between the oxytocin and related [[vasopressin]] receptors make it difficult to achieve high selectivity with peptide derivatives.<ref name="pmid17635137">{{cite journal | vauthors = Chini B, Manning M | title = Agonist selectivity in the oxytocin/vasopressin receptor family: new insights and challenges | journal = Biochemical Society Transactions | volume = 35 | issue = Pt 4 | pages = 737–41 | date = August 2007 | pmid = 17635137 | doi = 10.1042/BST0350737 }}</ref><ref name="pmid18655903">{{cite book | vauthors = Manning M, Stoev S, Chini B, Durroux T, Mouillac B, Guillon G | title = Peptide and non-peptide agonists and antagonists for the vasopressin and oxytocin V1a, V1b, V2 and OT receptors: research tools and potential therapeutic agents | volume = 170 | pages = 473–512 | year = 2008 | pmid = 18655903 | doi = 10.1016/S0079-6123(08)00437-8 | isbn = 978-0-444-53201-5 | series = Progress in Brain Research | chapter = Peptide and non-peptide agonists and antagonists for the vasopressin and oxytocin V1a, V1b, V2 and OT receptors: Research tools and potential therapeutic agents☆ }}</ref> However the search for a druggable, non-peptide template has led to several potent, highly selective, orally bioavailable oxytocin antagonists.<ref name="pmid20550119">{{cite journal | vauthors = Borthwick AD | title = Oral oxytocin antagonists | journal = Journal of Medicinal Chemistry | volume = 53 | issue = 18 | pages = 6525–38 | date = September 2010 | pmid = 20550119 | doi = 10.1021/jm901812z }}</ref> [[Oxytocin receptor agonist]]s have also been developed.<ref name="pmid34550574">{{cite book | vauthors = Nashar PE, Whitfield AA, Mikusek J, Reekie TA | title = Oxytocin | chapter = The Current Status of Drug Discovery for the Oxytocin Receptor | series = Methods Mol Biol | volume = 2384 | pages = 153–174 | date = 2022 | pmid = 34550574 | doi = 10.1007/978-1-0716-1759-5_10 | isbn = 978-1-0716-1758-8 | s2cid = 239090096 | chapter-url = }}</ref><ref name="pmid30509888">{{cite journal | vauthors = Gulliver D, Werry E, Reekie TA, Katte TA, Jorgensen W, Kassiou M | title = Targeting the Oxytocin System: New Pharmacotherapeutic Approaches | journal = Trends Pharmacol Sci | volume = 40 | issue = 1 | pages = 22–37 | date = January 2019 | pmid = 30509888 | doi = 10.1016/j.tips.2018.11.001 | s2cid = 54559394 | url = https://unsworks.unsw.edu.au/bitstreams/547ad575-bc60-4b4e-8bd3-681eff7ee47e/download| hdl = 1959.4/unsworks_81554 | hdl-access = free }}</ref>

=== Agonists ===
;Peptide
* [[Carbetocin]]
* [[Demoxytocin]]
* [[Lipo-oxytocin-1]]
* [[Merotocin]]
* [[Oxytocin]]

;Non-peptide
* [[LIT-001]] — improved [[social deficits]] in mice; non-selective over vasopressin receptors
* [[TC OT 39]] – non-selective over vasopressin receptors
* [[WAY-267,464]] – [[anxiolytic]] in mice; possibly non-selective over vasopressin receptors<ref name="pmid18655903"/><ref name="WO 2007050353">{{Ref patent3 | country = US | number = 2007/0117794 | status = application | title = Methods of treatment using oxytocin receptor agonists | pubdate = 2007-05-24 | fdate =  | pridate= 2005-10-24 | inventor = Rahman Z, Resnick L, Rosenzweig-Lipson SJ, Ring RH | assign1=  Wyeth Corp | google_patent_id = 3G2iAAAAEBAJ }}</ref><ref name="pmid19615387">{{cite journal | vauthors = Ring RH, Schechter LE, Leonard SK, Dwyer JM, Platt BJ, Graf R, Grauer S, Pulicicchio C, Resnick L, Rahman Z, Sukoff Rizzo SJ, Luo B, Beyer CE, Logue SF, Marquis KL, Hughes ZA, Rosenzweig-Lipson S | author-link4 = John Dwyer (medicine) | title = Receptor and behavioral pharmacology of WAY-267464, a non-peptide oxytocin receptor agonist | journal = Neuropharmacology | volume = 58 | issue = 1 | pages = 69–77 | date = January 2010 | pmid = 19615387 | doi = 10.1016/j.neuropharm.2009.07.016 | s2cid = 8592340 }}</ref>

=== Antagonists ===
;Peptide
* [[Atosiban]]
* [[Barusiban]]

;Non-peptide
* [[Epelsiban]]<ref name="Protein 2013">{{cite book|title=Methods and Principles in Medicinal Chemistry: Protein-Protein Interactions in Drug Discovery|date=January 2013|publisher=Wiley-VCH|location=Weinheim| doi = 10.1002/9783527648207.ch10 |isbn=978-3-527-33107-9|pages=225–256| vauthors = Borthwick AD, Liddle J | veditors = Domling A |chapter=Retosiban and Epelsiban: Potent and Selective Orally available Oxytocin Antagonists}}</ref>
* [[L-368,899]] (CAS# 148927-60-0)<ref name="pmid8126695">{{cite journal | vauthors = Williams PD, Anderson PS, Ball RG, Bock MG, Carroll L, Chiu SH, Clineschmidt BV, Culberson JC, Erb JM, Evans BE | title = 1-((7,7-Dimethyl-2(S)-(2(S)-amino-4-(methylsulfonyl)butyramido)bicyclo [2.2.1]-heptan-1(S)-yl)methyl)sulfonyl)-4-(2-methylphenyl)piperaz ine (L-368,899): an orally bioavailable, non-peptide oxytocin antagonist with potential utility for managing preterm labor | journal = Journal of Medicinal Chemistry | volume = 37 | issue = 5 | pages = 565–71 | date = March 1994 | pmid = 8126695 | doi = 10.1021/jm00031a004 }}</ref><ref name="pmid17583705">{{cite journal | vauthors = Boccia ML, Goursaud AP, Bachevalier J, Anderson KD, Pedersen CA | title = Peripherally administered non-peptide oxytocin antagonist, L368,899, accumulates in limbic brain areas: a new pharmacological tool for the study of social motivation in non-human primates | journal = Hormones and Behavior | volume = 52 | issue = 3 | pages = 344–51 | date = September 2007 | pmid = 17583705 | pmc = 2712625 | doi = 10.1016/j.yhbeh.2007.05.009 }}</ref>
* [[L-371,257]] (CAS# 162042-44-6)<ref name="pmid7473590">{{cite journal | vauthors = Williams PD, Clineschmidt BV, Erb JM, Freidinger RM, Guidotti MT, Lis EV, Pawluczyk JM, Pettibone DJ, Reiss DR, Veber DF | title = 1-(1-[4-[(N-acetyl-4-piperidinyl)oxy]-2-methoxybenzoyl]piperidin-4- yl)-4H-3,1-benzoxazin-2(1H)-one (L-371,257): a new, orally bioavailable, non-peptide oxytocin antagonist | journal = Journal of Medicinal Chemistry | volume = 38 | issue = 23 | pages = 4634–6 | date = November 1995 | pmid = 7473590 | doi = 10.1021/jm00023a002 }}</ref><ref name="pmid11992786">{{cite journal | vauthors = Wyatt PG, Allen MJ, Chilcott J, Foster A, Livermore DG, Mordaunt JE, Scicinski J, Woollard PM | title = Identification of potent and selective oxytocin antagonists. Part 1: indole and benzofuran derivatives | journal = Bioorganic & Medicinal Chemistry Letters | volume = 12 | issue = 10 | pages = 1399–404 | date = May 2002 | pmid = 11992786 | doi = 10.1016/S0960-894X(02)00159-2 }}</ref> – peripherally selective (i.e. poor [[blood brain barrier]] penetration, few central effects)<ref name="pmid16418825">{{cite journal | vauthors = Ring RH, Malberg JE, Potestio L, Ping J, Boikess S, Luo B, Schechter LE, Rizzo S, Rahman Z, Rosenzweig-Lipson S | title = Anxiolytic-like activity of oxytocin in male mice: behavioral and autonomic evidence, therapeutic implications | journal = Psychopharmacology | volume = 185 | issue = 2 | pages = 218–25 | date = April 2006 | pmid = 16418825 | doi = 10.1007/s00213-005-0293-z | s2cid = 13647805 }}</ref>
* [[L-372,662]]
* [[Nolasiban]]<ref>{{cite journal |vauthors=Kim SH, Riaposova L, Ahmed H, Kim SH, Riaposova L, Ahmed H, Pohl O, Chollet A, Gotteland JP, Hanyaloglu A, Bennett PR, Terzidou V |title=Oxytocin receptor antagonists, atosiban and nolasiban, inhibit prostaglandin F<sub>2α</sub>-induced contractions and inflammatory responses in human myometrium |journal=[[Scientific Reports]] |volume=9 |issue=5792 |year=2019 |page=5792 |doi=10.1038/s41598-019-42181-2|pmid=30962532 |pmc=6453954 |bibcode=2019NatSR...9.5792K }}</ref>
* [[Retosiban]] (GSK-221,149)<ref name="Protein 2013" />
* [[SSR-126,768]]
* [[WAY-162,720]] – centrally active following peripheral administration

== References ==
{{Reflist|33em}}

==External links==
{{Commons category|Oxytocin receptors}}
*{{MeshName|Oxytocin+receptor}}
*{{cite web | url = https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/8529 | title = Symbol Report: OXTR | publisher = HUGO Gene Nomenclature Committee }}
*{{cite web | url = http://www.iuphar-db.org/GPCR/ReceptorDisplayForward?receptorID=2966 | title = Vasopressin and Oxytocin Receptors: OT | work = IUPHAR Database of Receptors and Ion Channels | publisher = International Union of Basic and Clinical Pharmacology }}

{{NLM content}}
{{G protein-coupled receptors}}
{{Neuropeptide receptors}}
{{Oxytocin and vasopressin receptor modulators}}

[[Category:G protein-coupled receptors]]
[[Category:Genes on human chromosome 3]]