OT receptor | Vasopressin and oxytocin receptors | IUPHAR/BPS Guide to PHARMACOLOGY

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OT receptor

Target not currently curated in GtoImmuPdb

Target id: 369

Nomenclature: OT receptor

Family: Vasopressin and oxytocin receptors

Annotation status:  image of a green circle Annotated and expert reviewed. Please contact us if you can help with updates.  » Email us

Gene and Protein Information
class A G protein-coupled receptor
Species TM AA Chromosomal Location Gene Symbol Gene Name Reference
Human 7 389 3p25 OXTR oxytocin receptor 51,53-54,62
Mouse 7 388 6 Oxtr oxytocin receptor 55
Rat 7 388 4q42 Oxtr oxytocin receptor 31,76
Previous and Unofficial Names
Database Links
Specialist databases
GPCRDB oxyr_human (Hs), oxyr_mouse (Mm), oxyr_rat (Rn)
Other databases
ChEMBL Target
DrugBank Target
Ensembl Gene
Entrez Gene
Human Protein Atlas
RefSeq Nucleotide
RefSeq Protein
Natural/Endogenous Ligands
oxytocin {Sp: Human, Mouse, Rat}
vasopressin {Sp: Human, Mouse, Rat}
Comments: Oxytocin is the principal endogenous ligand
Potency order of endogenous ligands (Human)
oxytocin (OXT, P01178) > vasopressin (AVP, P01185)  [3,22-24,43,49,53]

Download all structure-activity data for this target as a CSV file

Key to terms and symbols View all chemical structures Click column headers to sort
Ligand Sp. Action Value Parameter Reference
[3H]AVP (human, mouse, rat) Hs Partial agonist 8.8 – 8.9 pKd 15,22
pKd 8.8 – 8.9 [15,22]
[3H]OT (human, mouse, rat) Hs Full agonist 8.2 – 9.5 pKd 22,40,49,53
pKd 8.2 – 9.5 (Kd 6.31x10-9 – 3.16x10-10 M) [22,40,49,53]
arginine vasotocin Hs Full agonist 9.4 pKi 22-23
pKi 9.4 [22-23]
oxytocin {Sp: Human, Mouse, Rat} Hs Full agonist 8.2 – 9.6 pKi 3,22-24,43,49
pKi 8.2 – 9.6 [3,22-24,43,49]
[Phe3]OT Hs Full agonist 8.8 pKi 22-23
pKi 8.8 [22-23]
oxytocin {Sp: Human, Mouse, Rat} Rn Full agonist 8.7 pKi 24
pKi 8.7 [24]
vasopressin {Sp: Human, Mouse, Rat} Hs Partial agonist 7.3 – 9.3 pKi 3,15,21-23,29,43,49
pKi 7.3 – 9.3 [3,15,21-23,29,43,49]
dAVP Hs Full agonist 8.3 pKi 21
pKi 8.3 [21]
[Thr4,Gly7]OT Hs Full agonist 8.2 – 8.4 pKi 23,32,49
pKi 8.2 – 8.4 [23,32,49]
d[Cha4]AVP Hs Full agonist 7.1 – 7.7 pKi 29,43
pKi 7.1 – 7.7 [29,43]
d[Leu4]LVP Rn Full agonist 7.2 pKi 69
pKi 7.2 [69]
desmopressin Hs Full agonist 6.7 – 7.6 pKi 22,49
pKi 6.7 – 7.6 [22,49]
d[Leu4,Dap8]VP Rn Full agonist 6.9 pKi 69
pKi 6.9 [69]
d[Leu4]AVP Hs Full agonist 6.7 pKi 21
pKi 6.7 [21]
LIT-001 Hs Agonist 6.7 pKi 39
pKi 6.7 (Ki 2.26x10-7 M) [39]
Description: Binding affinity determined by a TR-FRET binding assay on HEK cells expressing SNAP-tagged OT receptors using 20 nM fluorescent DY647 and increasing concentration of competitor.
d[Cha4,Dab8]VP Rn Full agonist 6.4 pKi 69
pKi 6.4 [69]
d[Cha4]LVP Rn Full agonist 6.2 pKi 69
pKi 6.2 [69]
View species-specific agonist tables
Key to terms and symbols View all chemical structures Click column headers to sort
Ligand Sp. Action Value Parameter Reference
[35S]non-peptide OT antagonist Hs Antagonist 10.4 pKd 56
pKd 10.4 (Kd 4.2x10-11 M) [56]
d(CH2)5[Tyr(Me)2,Thr4,Tyr(3125I)-NH29]OVT Hs Antagonist 9.7 – 10.0 pKd 15,22-23
pKd 9.7 – 10.0 [15,22-23]
d(CH2)5[Tyr(Me)2,Thr4,Phe(3125I,4N3)-NH29]OVT Hs Antagonist 9.6 pKd 15
pKd 9.6 [15]
d(CH2)5[Tyr(Me)2,Thr4,Tyr-NH29]OVT Hs Antagonist 9.2 – 10.0 pKi 43,60
pKi 9.2 – 10.0 [43,60]
L-366,875 Hs Antagonist 9.5 pKi 49
pKi 9.5 [49]
L023103 Hs Antagonist 9.2 pKi 72
pKi 9.2 [72]
L023103 Rn Antagonist 9.2 pKi 72
pKi 9.2 [72]
retosiban Hs Antagonist 9.2 pKi 61
pKi 9.2 (Ki 6.5x10-10 M) [61]
d(CH2)5[Tyr(Me)2,Thr4,Phe(3I,4N3)-NH29]OVT Hs Antagonist 9.0 pKi 15
pKi 9.0 [15]
SSR126768A Hs Antagonist 8.8 – 9.1 pKi 78
pKi 8.8 – 9.1 (Ki 1.5x10-9 – 9x10-10 M) [78]
compound 37 [PMID: 16250654] Hs Antagonist 8.9 pKi 13
pKi 8.9 [13]
L-371,257 Hs Antagonist 8.8 pKi 43
pKi 8.8 [43]
L-366,948 Hs Antagonist 8.6 pKi 49
pKi 8.6 [49]
L-365,209 Hs Antagonist 8.5 pKi 49
pKi 8.5 [49]
L-368,930 Hs Antagonist 8.5 pKi 49
pKi 8.5 [49]
L-369,020 Hs Antagonist 8.5 pKi 49
pKi 8.5 [49]
L-366,682 Hs Antagonist 8.4 pKi 49
pKi 8.4 [49]
L-368,228 Hs Antagonist 8.4 pKi 49
pKi 8.4 [49]
L-372662 Hs Antagonist 8.4 pKi 11
pKi 8.4 [11]
d(CH2)5[Tyr(Me)2]AVP Hs Antagonist 8.3 pKi 49
pKi 8.3 [49]
L-368,899 Hs Antagonist 8.1 pKi 49
pKi 8.1 [49]
L-367,938 Hs Antagonist 7.9 pKi 49
pKi 7.9 [49]
nelivaptan Hs Antagonist 6.8 – 8.8 pKi 43,79
pKi 6.8 – 8.8 [43,79]
LS-192629 Hs Antagonist 7.6 – 7.8 pKi 24
pKi 7.6 – 7.8 [24]
L-367,773 Hs Antagonist 7.6 pKi 49
pKi 7.6 [49]
atosiban Rn Antagonist 7.1 pKi 24
pKi 7.1 [24]
LS-192629 Rn Antagonist 6.9 pKi 24
pKi 6.9 [24]
OPC-21268 Hs Antagonist 6.8 pKi 49
pKi 6.8 [49]
atosiban Hs Antagonist 6.0 – 7.6 pKi 3,24,49,60,78
pKi 6.0 – 7.6 [3,24,49,60,78]
relcovaptan Hs Antagonist 6.5 – 7.0 pKi 3,43
pKi 6.5 – 7.0 [3,43]
L-366,509 Hs Antagonist 6.6 pKi 49
pKi 6.6 [49]
balovaptan Hs Antagonist 5.2 pKi 77
pKi 5.2 (Ki 7.002x10-6 M) [77]
Ro5028442 Hs Antagonist 5.0 pKi 74
pKi 5.0 (Ki 9.891x10-6 M) [74]
[Mpa1,D-Tyr(Et)2,D-Tic7,D-Tic9]OT Hs Antagonist 7.6 pIC50 38
pIC50 7.6 [38]
[Mpa1,D-Tyr(Et)2,D-Tic7]OT Hs Antagonist 7.3 pIC50 38
pIC50 7.3 [38]
[Mpa1,D-Tyr(Et)2,D-Tic7,Aib9]OT Hs Antagonist 7.1 pIC50 38
pIC50 7.1 [38]
View species-specific antagonist tables
Immuno Process Associations
Immuno Process:  Cytokine production & signalling
GO Annotations:  Associated to 1 GO processes, IEA only
click arrow to show/hide IEA associations
GO:0034097 response to cytokine IEA
Primary Transduction Mechanisms
Transducer Effector/Response
Gq/G11 family Phospholipase C stimulation
References:  81,83
Secondary Transduction Mechanisms
Transducer Effector/Response
Gi/Go family Adenylate cyclase inhibition
References:  83-84
Tissue Distribution
Species:  Human
Technique:  In situ hybridisation and immunohistochemistry.
References:  19
Corpus cavernosum
Species:  Human
Technique:  RT-PCR, Northern blotting, immunohistochemistry, Western blotting and radioligand binding.
References:  90
Species:  Human
Technique:  RT-PCR.
References:  27
Ovary: cumulus cells.
Species:  Human
Technique:  RT-PCR.
References:  41
Breast tissue.
Species:  Human
Technique:  Immunocytochemistry and RT-PCR.
References:  18
Vascular endothelial cells.
Species:  Human
Technique:  RT-PCR.
References:  87
Mammary gland.
Species:  Human
Technique:  Immunohistochemistry.
References:  52
Species:  Human
Technique:  Immunofluorescence and Western blotting.
References:  26
Species:  Human
Technique:  RT-PCR.
References:  91
Brain and spinal cord: brainstem; dorsal horn of upper spinal cord
Species:  Human
Technique:  Radioligand binding (autoradiography)
References:  59
Fetal heart > adult heart.
Species:  Human
Technique:  RT-PCR.
References:  48
Species:  Human
Technique:  RT-PCR and immunocytochemistry.
References:  37
Species:  Mouse
Technique:  Immunohistochemistry.
References:  12
Thymic epithelial cells.
Species:  Mouse
Technique:  in situ hybridisation.
References:  45
Species:  Rat
Technique:  Radioligand binding
References:  6
Brain: ventromedial nucleus of the hypothalamus, central amygdaloid nucleus, the islands of Calleja, olfactory nucleus, lateral septum, dorsal motor nucleus of the vagus nerve, taenia tecta, dorsolateral caudate putamen, ventral pallidum, accumbens, bed nucleus of the stria terminalis, thalamic paraventricular nucleus, lateral, basolateral, and medial amygdala, amygdaloid-hippocampal area.
Species:  Rat
Technique:  Radioligand binding (autoradiography)
References:  33,88
Species:  Rat
Technique:  Northern blotting, RT-PCR and in situ hybridisation
References:  17
Species:  Rat
Technique:  in situ hybridisation.
References:  68
Brain, pituitary, mammary glands, uterus.
Brain: ventromedial hypothalamus, bed nucleus of the stria terminalis, ventral pallidum, paraventricular nucleus, dorsal part of the supraoptic nucleus.
Pituitary: anterior and posterior lobes.
Species:  Rat
Technique:  immunocytochemistry.
References:  1
Species:  Rat
Technique:  Radioligand binding.
References:  10
Species:  Rat
Technique:  RT-PCR, immunohistochemistry, Western blotting and radioligand binding.
References:  95
Species:  Rat
Technique:  Radioligand binding
References:  34
Species:  Rat
Technique:  in situ hybridisation.
References:  44
Mammary gland.
Species:  Rat
Technique:  in situ hybridisation.
References:  16
Brain: ventromedial nucleus of the hypothalamus, anterior olfactory nucleus, intermediate bed nucleus of the stria terminalis, frontal cortex, piriform cortex, supraoptic nucleus, arcuate nucleus, suprachiasmatic nucleus, ventral subiculum, cortical amygdala, subfornical organ, mammillary complex > ateral septal nucleus, medial preoptic area, ventral portions of the bed nucleus of the stria terminalis, paraventricular nucleus of the hypothalamus, dorsal caudoputamen, entorhinal cortex, hippocampus, paraventricular nucleus of the thalamus, dorsal raphe, pontine nuclei, substantia nigra pars compacta, ventral tegmental area.
Species:  Rat
Technique:  in situ hybridisation.
References:  67,89
Species:  Rat
Technique:  RT-PCR.
References:  25,57,76
Mammary gland.
Species:  Rat
Technique:  Radioligand binding.
References:  70,82
CNS: ventromedial hypothalamus.
Species:  Rat
Technique:  in situ hybridisation.
References:  9
Species:  Rat
Technique:  Immunocytochemistry.
References:  48
Expression Datasets

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Log average relative transcript abundance in mouse tissues measured by qPCR from Regard, J.B., Sato, I.T., and Coughlin, S.R. (2008). Anatomical profiling of G protein-coupled receptor expression. Cell, 135(3): 561-71. [PMID:18984166] [Raw data: website]

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Functional Assays
Measurement of inositol phosphate accumulation in CHO cells transfected with the rat OT receptor.
Species:  Rat
Tissue:  CHO cells.
Response measured:  Stimulation of IP accumulation.
References:  50
Measurement of calcium levels in CHO cells transfected with the rat OT receptor.
Species:  Rat
Tissue:  CHO cells.
Response measured:  Stimulation of calcium mobilisation.
References:  50,81
Measurement of arachidonic acid and PGE2 levels in CHO cells transfected with the rat OT receptor.
Species:  Rat
Tissue:  CHO cells.
Response measured:  Stimulation of arachidonic acid release followed by PGE2 synthesis.
References:  50
Measurement of ERK2 phosphorylation in CHO cells transfected with the rat OT receptor.
Species:  Rat
Tissue:  CHO cells.
Response measured:  Stimulation of ERK2 phosphorylation.
References:  83
Physiological Functions
Inhibition of food and water intake.
Species:  Rat
Tissue:  In vivo.
References:  7,65
Milk ejection.
Species:  Mouse
Tissue:  In vivo.
References:  64,94
Stimulation of parturition.
Species:  Rat
Tissue:  In vivo.
References:  5,20,73
Uterine contractions.
Species:  Rat
Tissue:  In vivo.
References:  2,61
Muscle contractions.
Species:  Human
Tissue:  Myometrium strips.
References:  71,92
Muscle contractions.
Species:  Rat
Tissue:  Myometrium strips.
References:  8,35
Noradrenaline release.
Species:  Rat
Tissue:  In vivo (supraoptic nucleus).
References:  66
Modulation of exercise-induced tachycardia.
Species:  Rat
Tissue:  In vivo (heart).
References:  14
Species:  Rat
Tissue:  Heart.
References:  48
Facilitation of sperm transport during ejaculation.
Species:  Human
Tissue:  In vivo (epididymis).
References:  37
Stimulation of renin secretion.
Species:  Rat
Tissue:  In vivo (kidney).
References:  46,58,80
Stimulation of urinary Na+ excretion in response to continual (not pulsatile) administration of oxytocin.
Species:  Rat
Tissue:  In vivo (kidney).
References:  80
Regulation of stress-induced antinociception.
Species:  Mouse
Tissue:  Dorsal horn neurones in spinal slices.
References:  75
Attenuation of stress-induced hypothalamic-pituitary-adrenal axis activity.
Species:  Rat
Tissue:  In vivo.
References:  63,93
Development of social memory.
Species:  Mouse
Tissue:  In vivo.
References:  28,36
Physiological Consequences of Altering Gene Expression
Female OT receptor knockout mice exhibit defects in lactation and maternal nuturing; male OT receptor knockout mice have deficits in social discrimination and elevated aggressive behaviour.
Species:  Mouse
Technique:  Gene targeting in embryonic stem cells.
References:  85
Phenotypes, Alleles and Disease Models Mouse data from MGI

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Allele Composition & genetic background Accession Phenotype Id Phenotype Reference
Oxtrtm1Wsy Oxtrtm1Wsy/Oxtrtm1Wsy
involves: 129S1/Sv * 129X1/SvJ
MGI:109147  MP:0002152 abnormal brain morphology PMID: 18356275 
Oxtrtm1.1Knis Oxtrtm1.1Knis/Oxtrtm1.1Knis
involves: 129P2/OlaHsd * C57BL/6J
MGI:109147  MP:0001386 abnormal maternal nurturing PMID: 16249339 
Oxtrtm1.2Wsy Oxtrtm1.2Wsy/Oxtrtm1.2Wsy
involves: 129S1/Sv * 129X1/SvJ * C57BL/6 * CBA * SJL
MGI:109147  MP:0003838 abnormal milk ejection PMID: 18356275 
Oxtrtm1.1Knis Oxtrtm1.1Knis/Oxtrtm1.1Knis
involves: 129P2/OlaHsd * C57BL/6J
MGI:109147  MP:0001384 abnormal pup retrieval PMID: 16249339 
Oxtrtm1.1Knis Oxtrtm1.1Knis/Oxtrtm1.1Knis
involves: 129P2/OlaHsd * C57BL/6J
MGI:109147  MP:0001360 abnormal social investigation PMID: 16249339 
Oxtrtm1.1Wsy|Tg(Camk2a-cre)1Szi Oxtrtm1.1Wsy/Oxtrtm1.1Wsy,Tg(Camk2a-cre)1Szi/0
involves: 129S1/Sv * 129X1/SvJ * C57BL/6 * CBA * SJL
MGI:109147  MGI:2177766  MP:0001360 abnormal social investigation PMID: 18356275 
Oxtrtm1.2Wsy Oxtrtm1.2Wsy/Oxtrtm1.2Wsy
involves: 129S1/Sv * 129X1/SvJ * C57BL/6 * CBA * SJL
MGI:109147  MP:0001360 abnormal social investigation PMID: 18356275 
Oxtrtm1.1Knis Oxtrtm1.1Knis/Oxtrtm1.1Knis
involves: 129P2/OlaHsd * C57BL/6J
MGI:109147  MP:0001529 abnormal vocalization PMID: 16249339 
Oxtrtm1.1Knis Oxtrtm1.1Knis/Oxtrtm1.1Knis
involves: 129P2/OlaHsd * C57BL/6J
MGI:109147  MP:0009326 absent maternal crouching PMID: 16249339 
Oxtrtm1.1Wsy|Tg(Camk2a-cre)1Szi Oxtrtm1.1Wsy/Oxtrtm1.1Wsy,Tg(Camk2a-cre)1Szi/0
involves: 129S1/Sv * 129X1/SvJ * C57BL/6 * CBA * SJL
MGI:109147  MGI:2177766  MP:0001262 decreased body weight PMID: 18356275 
Oxtr+|Oxtrtm1.2Wsy Oxtrtm1.2Wsy/Oxtr+
involves: 129S1/Sv * 129X1/SvJ * C57BL/6 * CBA * SJL
MGI:109147  MP:0001935 decreased litter size PMID: 18356275 
Oxtrtm1.1Knis Oxtrtm1.1Knis/Oxtrtm1.1Knis
involves: 129P2/OlaHsd * C57BL/6J
MGI:109147  MP:0001399 hyperactivity PMID: 16249339 
Oxtrtm1.1Knis Oxtrtm1.1Knis/Oxtrtm1.1Knis
involves: 129P2/OlaHsd * C57BL/6J
MGI:109147  MP:0001353 increased aggression towards mice PMID: 16249339 
Oxtrtm1.1Knis Oxtrtm1.1Knis/Oxtrtm1.1Knis
involves: 129P2/OlaHsd * C57BL/6J
MGI:109147  MP:0010249 lactation failure PMID: 16249339 
Oxtrtm1.1Wsy Oxtrtm1.1Wsy/Oxtrtm1.1Wsy
involves: 129S1/Sv * 129X1/SvJ * C57BL/6 * SJL
MGI:109147  MP:0002169 no abnormal phenotype detected PMID: 18356275 
Biologically Significant Variants
Type:  Single nucleotide polymorphism
Species:  Human
Description:  SNPs in the OT receptor gene may be linked to autism.
SNP accession: 
References:  47
General Comments
The number of OT receptors in the uterus increases near to parturition [25].

The neurohypophysial hormone oxytocin (OT) was the first peptide hormone to have its structure determined and the first to be chemically synthesised in biologically active form [30]. Circulating OT is associated chiefly with the contraction of uterine smooth muscle at term and of myoepithelial cells that surround the alveoli of the mammary gland during lactation through its action on OT receptors. Today, it is recognised that OT exerts a wide spectrum of central and peripheral effects. These actions of OT range from the modulation of neuroendocrine reflexes to the establishment of complex social and bonding behaviours related to the reproduction and care of the offspring [42]. OT receptors form homodimers in vitro and may heterodimerise with vasopressin V1A and V2 receptors [86].

A peptide antagonist, [1-deamino,D-Tyr(Et)2,Thr4,Orn8]vasotocin (atosiban), shown to inhibit uterine contractions in women, threatened and established pre-term labour [4], has been approved for clinical use in Europe.


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1. Adan RA, Van Leeuwen FW, Sonnemans MA, Brouns M, Hoffman G, Verbalis JG, Burbach JP. (1995) Rat oxytocin receptor in brain, pituitary, mammary gland, and uterus: partial sequence and immunocytochemical localization. Endocrinology, 136 (9): 4022-8. [PMID:7649111]

2. Ahn TG, Han SJ, Cho YS, An TH, Pak SC, Flouret G. (2004) In vivo activity of the potent oxytocin antagonist on uterine activity in the rat. In Vivo, 18 (6): 763-6. [PMID:15646817]

3. Akerlund M, Bossmar T, Brouard R, Kostrzewska A, Laudanski T, Lemancewicz A, Serradeil-Le Gal C, Steinwall M. (1999) Receptor binding of oxytocin and vasopressin antagonists and inhibitory effects on isolated myometrium from preterm and term pregnant women. Br J Obstet Gynaecol, 106 (10): 1047-53. [PMID:10519430]

4. Akerlund M, Carlsson AM, Melin P, Trojnar J. (1985) The effect on the human uterus of two newly developed competitive inhibitors of oxytocin and vasopressin. Acta Obstet Gynecol Scand, 64 (6): 499-504. [PMID:4061066]

5. Alexandrova M, Soloff MS. (1980) Oxytocin receptors and parturition. I. Control of oxytocin receptor concentration in the rat myometrium at term. Endocrinology, 106 (3): 730-5. [PMID:6243547]

6. Antoni FA. (1986) Oxytocin receptors in rat adenohypophysis: evidence from radioligand binding studies. Endocrinology, 119 (5): 2393-5. [PMID:3021442]

7. Arletti R, Benelli A, Bertolini A. (1990) Oxytocin inhibits food and fluid intake in rats. Physiol. Behav., 48 (6): 825-30. [PMID:2087513]

8. Atke A, Vilhardt H. (1987) Uterotonic activity and myometrial receptor affinity of 1-deamino-1-carba-2-tyrosine(O-methyl)-oxytocin. Acta Endocrinol., 115 (1): 155-60. [PMID:3035851]

9. Bale TL, Pedersen CA, Dorsa DM. (1995) CNS oxytocin receptor mRNA expression and regulation by gonadal steroids. Adv. Exp. Med. Biol., 395: 269-80. [PMID:8713977]

10. Bathgate RA, Sernia C. (1994) Characterization and localization of oxytocin receptors in the rat testis. J. Endocrinol., 141 (2): 343-52. [PMID:8046305]

11. Bell IM, Erb JM, Freidinger RM, Gallicchio SN, Guare JP, Guidotti MT, Halpin RA, Hobbs DW, Homnick CF, Kuo MS et al.. (1998) Development of orally active oxytocin antagonists: studies on 1-(1-[4-[1-(2-methyl-1-oxidopyridin-3-ylmethyl)piperidin-4-yloxy]-2- methoxybenzoyl]piperidin-4-yl)-1,4-dihydrobenz[d][1,3]oxazin-2-one (L-372,662) and related pyridines. J. Med. Chem., 41 (12): 2146-63. [PMID:9622556]

12. Beretsos P, Loutradis D, Koussoulakos S, Margaritis LH, Kiapekou E, Mastorakos G, Papaspirou I, Makris N, Makrigiannakis A, Antsaklis A. (2006) Oxytocin receptor is differentially expressed in mouse endometrium and embryo during blastocyst implantation. Ann. N. Y. Acad. Sci., 1092: 466-79. [PMID:17308174]

13. Borthwick AD, Davies DE, Exall AM, Livermore DG, Sollis SL, Nerozzi F, Allen MJ, Perren M, Shabbir SS, Woollard PM et al.. (2005) 2,5-diketopiperazines as potent, selective, and orally bioavailable oxytocin antagonists. 2. Synthesis, chirality, and pharmacokinetics. J. Med. Chem., 48 (22): 6956-69. [PMID:16250654]

14. Braga DC, Mori E, Higa KT, Morris M, Michelini LC. (2000) Central oxytocin modulates exercise-induced tachycardia. Am. J. Physiol. Regul. Integr. Comp. Physiol., 278 (6): R1474-82. [PMID:10848513]

15. Breton C, Chellil H, Kabbaj-Benmansour M, Carnazzi E, Seyer R, Phalipou S, Morin D, Durroux T, Zingg H, Barberis C et al.. (2001) Direct identification of human oxytocin receptor-binding domains using a photoactivatable cyclic peptide antagonist: comparison with the human V1a vasopressin receptor. J. Biol. Chem., 276 (29): 26931-41. [PMID:11337500]

16. Breton C, Di Scala-Guenot D, Zingg HH. (2001) Oxytocin receptor gene expression in rat mammary gland: structural characterization and regulation. J. Mol. Endocrinol., 27 (2): 175-89. [PMID:11564602]

17. Breton C, Pechoux C, Morel G, Zingg HH. (1995) Oxytocin receptor messenger ribonucleic acid: characterization, regulation, and cellular localization in the rat pituitary gland. Endocrinology, 136 (7): 2928-36. [PMID:7540544]

18. Bussolati G, Cassoni P, Ghisolfi G, Negro F, Sapino A. (1996) Immunolocalization and gene expression of oxytocin receptors in carcinomas and non-neoplastic tissues of the breast. Am. J. Pathol., 148 (6): 1895-903. [PMID:8669475]

19. Cassoni P, Marrocco T, Sapino A, Allia E, Bussolati G. (2004) Evidence of oxytocin/oxytocin receptor interplay in human prostate gland and carcinomas. Int. J. Oncol., 25 (4): 899-904. [PMID:15375538]

20. Chan WY, Chen DL. (1992) Myometrial oxytocin receptors and prostaglandin in the parturition process in the rat. Biol. Reprod., 46 (1): 58-64. [PMID:1312364]

21. Cheng LL, Stoev S, Manning M, Derick S, Pena A, Mimoun MB, Guillon G. (2004) Design of potent and selective agonists for the human vasopressin V1b receptor based on modifications of [deamino-cys1]arginine vasopressin at position 4. J Med Chem, 47: 2375-2388. [PMID:15084136]

22. Chini B, Mouillac B, Ala Y, Balestre MN, Trumpp-Kallmeyer S, Hoflack J, Elands J, Hibert M, Manning M, Jard S et al.. (1995) Tyr115 is the key residue for determining agonist selectivity in the V1a vasopressin receptor. EMBO J., 14 (10): 2176-82. [PMID:7774575]

23. Chini B, Mouillac B, Balestre MN, Trumpp-Kallmeyer S, Hoflack J, Hibert M, Andriolo M, Pupier S, Jard S, Barberis C. (1996) Two aromatic residues regulate the response of the human oxytocin receptor to the partial agonist arginine vasopressin. FEBS Lett., 397 (2-3): 201-6. [PMID:8955347]

24. Cirillo R, Gillio Tos E, Schwarz MK, Quattropani A, Scheer A, Missotten M, Dorbais J, Nichols A, Borrelli F, Giachetti C et al.. (2003) Pharmacology of (2S,4Z)-N-[(2S)-2-hydroxy-2-phenylethyl]-4-(methoxyimino) -1-[(2'-methyl[1,1'-biphenyl]-4-yl)carbonyl]-2-pyrrolidinecarboxamide, a new potent and selective nonpeptide antagonist of the oxytocin receptor. J. Pharmacol. Exp. Ther., 306 (1): 253-61. [PMID:12660315]

25. Clerget MS, Elalouf JM, Germain G. (1997) Quantitative reverse transcription and polymerase chain reaction analysis of oxytocin and vasopressin receptor mRNAs in the rat uterus near parturition. Mol. Cell. Endocrinol., 136 (1): 79-89. [PMID:9510070]

26. Colucci S, Colaianni G, Mori G, Grano M, Zallone A. (2002) Human osteoclasts express oxytocin receptor. Biochem. Biophys. Res. Commun., 297 (3): 442-5. [PMID:12270111]

27. Copland JA, Ives KL, Simmons DJ, Soloff MS. (1999) Functional oxytocin receptors discovered in human osteoblasts. Endocrinology, 140 (9): 4371-4. [PMID:10465312]

28. Crawley JN, Chen T, Puri A, Washburn R, Sullivan TL, Hill JM, Young NB, Nadler JJ, Moy SS, Young LJ et al.. (2007) Social approach behaviors in oxytocin knockout mice: comparison of two independent lines tested in different laboratory environments. Neuropeptides, 41 (3): 145-63. [PMID:17420046]

29. Derick S, Cheng LL, Voirol MJ, Stoev S, Giacomini M, Wo NC, Szeto HH, Ben Mimoun M, Andres M, Gaillard RC et al.. (2002) [1-deamino-4-cyclohexylalanine] arginine vasopressin: a potent and specific agonist for vasopressin V1b receptors. Endocrinology, 143 (12): 4655-64. [PMID:12446593]

30. Du Vigneaud V, Ressler C, Trippett S. (1953) The sequence of amino acids in oxytocin, with a proposal for the structure of oxytocin. J Biol Chem, 205: 949-957. [PMID:13129273]

31. Dutil J, Moujahidine M, Lemieux C, Jankowski M, Gutkowska J, Deng AY. (2001) Chromosomal and comparative mapping of rat oxytocin, oxytocin receptor and vasopressin genes. Cytogenet. Cell Genet., 93 (1-2): 57-9. [PMID:11474180]

32. Elands J, Barberis C, Jard S. (1988) [3H]-[Thr4,Gly7]OT: a highly selective ligand for central and peripheral OT receptors. Am. J. Physiol., 254 (1 Pt 1): E31-8. [PMID:2827511]

33. Elands J, Beetsma A, Barberis C, de Kloet ER. (1988) Topography of the oxytocin receptor system in rat brain: an autoradiographical study with a selective radioiodinated oxytocin antagonist. J. Chem. Neuroanat., 1 (6): 293-302. [PMID:2855912]

34. Elands J, Resink A, De Kloet ER. (1988) Oxytocin receptors in the rat thymic gland. Eur J Pharmacol, 151: 345-346. [PMID:2844558]

35. Engstrøm T, Atke A, Vilhardt H. (1988) Oxytocin receptors and contractile response of the myometrium after long term infusion of prostaglandin F2 alpha, indomethacin, oxytocin and an oxytocin antagonist in rats. Regul. Pept., 20 (1): 65-72. [PMID:2832879]

36. Ferguson JN, Young LJ, Hearn EF, Matzuk MM, Insel TR, Winslow JT. (2000) Social amnesia in mice lacking the oxytocin gene. Nat. Genet., 25 (3): 284-8. [PMID:10888874]

37. Filippi S, Vannelli GB, Granchi S, Luconi M, Crescioli C, Mancina R, Natali A, Brocchi S, Vignozzi L, Bencini E et al.. (2002) Identification, localization and functional activity of oxytocin receptors in epididymis. Mol. Cell. Endocrinol., 193 (1-2): 89-100. [PMID:12161007]

38. Fragiadaki M, Magafa V, Borovicková L, Slaninová J, Cordopatis P. (2007) Synthesis and biological activity of oxytocin analogues containing conformationally-restricted residues in position 7. Eur J Med Chem, 42 (6): 799-806. [PMID:17316912]

39. Frantz MC, Pellissier LP, Pflimlin E, Loison S, Gandía J, Marsol C, Durroux T, Mouillac B, Becker JAJ, Le Merrer J et al.. (2018) LIT-001, the First Nonpeptide Oxytocin Receptor Agonist that Improves Social Interaction in a Mouse Model of Autism. J. Med. Chem., 61 (19): 8670-8692. [PMID:30199637]

40. Fuchs AR, Fuchs F, Husslein P, Soloff MS, Fernström MJ. (1982) Oxytocin receptors and human parturition: a dual role for oxytocin in the initiation of labor. Science, 215 (4538): 1396-8. [PMID:6278592]

41. Furuya K, Mizumoto Y, Makimura N, Mitsui C, Murakami M, Tokuoka S, Ishikawa N, Imaizumi E, Katayama E, Seki K et al.. (1995) Gene expressions of oxytocin and oxytocin receptor in cumulus cells of human ovary. Horm. Res., 44 Suppl 2: 47-9. [PMID:7545643]

42. Gimpl G, Fahrenholz F. (2001) The oxytocin receptor system: structure, function, and regulation. Physiol. Rev., 81 (2): 629-83. [PMID:11274341]

43. Griffante C, Green A, Curcuruto O, Haslam CP, Dickinson BA, Arban R. (2005) Selectivity of d[Cha4]AVP and SSR149415 at human vasopressin and oxytocin receptors: evidence that SSR149415 is a mixed vasopressin V1b/oxytocin receptor antagonist. Br J Pharmacol, 146: 744-751. [PMID:16158071]

44. Gutkowska J, Jankowski M, Lambert C, Mukaddam-Daher S, Zingg HH, McCann SM. (1997) Oxytocin releases atrial natriuretic peptide by combining with oxytocin receptors in the heart. Proc. Natl. Acad. Sci. U.S.A., 94 (21): 11704-9. [PMID:9326674]

45. Hansenne I, Rasier G, Péqueux C, Brilot F, Renard Ch, Breton C, Greimers R, Legros JJ, Geenen V, Martens HJ. (2005) Ontogenesis and functional aspects of oxytocin and vasopressin gene expression in the thymus network. J. Neuroimmunol., 158 (1-2): 67-75. [PMID:15589039]

46. Huang W, Sjöquist M, Skott O, Stricker EM, Sved AF. (2000) Oxytocin-induced renin secretion in conscious rats. Am J Physiol Regul Integr Comp Physiol, 278: R226-R230. [PMID:10644643]

47. Jacob S, Brune CW, Carter CS, Leventhal BL, Lord C, Cook Jr EH. (2007) Association of the oxytocin receptor gene (OXTR) in Caucasian children and adolescents with autism. Neurosci. Lett., 417 (1): 6-9. [PMID:17383819]

48. Jankowski M, Danalache B, Wang D, Bhat P, Hajjar F, Marcinkiewicz M, Paquin J, McCann SM, Gutkowska J. (2004) Oxytocin in cardiac ontogeny. Proc. Natl. Acad. Sci. U.S.A., 101 (35): 13074-9. [PMID:15316117]

49. Jasper JR, Harrell CM, O'Brien JA, Pettibone DJ. (1995) Characterization of the human oxytocin receptor stably expressed in 293 human embryonic kidney cells. Life Sci., 57 (24): 2253-61. [PMID:7475979]

50. Jeng YJ, Lolait SJ, Strakova Z, Chen C, Copland JA, Mellman D, Hellmich MR, Soloff MS. (1996) Molecular cloning and functional characterization of the oxytocin receptor from a rat pancreatic cell line (RINm5F). Neuropeptides, 30 (6): 557-65. [PMID:9004255]

51. Kimura T. (1995) Investigation of the oxytocin receptor at the molecular level. Adv. Exp. Med. Biol., 395: 259-68. [PMID:8713976]

52. Kimura T, Ito Y, Einspanier A, Tohya K, Nobunaga T, Tokugawa Y, Takemura M, Kubota Y, Ivell R, Matsuura N et al.. (1998) Expression and immunolocalization of the oxytocin receptor in human lactating and non-lactating mammary glands. Hum. Reprod., 13 (9): 2645-53. [PMID:9806301]

53. Kimura T, Makino Y, Saji F, Takemura M, Inoue T, Kikuchi T, Kubota Y, Azuma C, Nobunaga T, Tokugawa Y et al.. (1994) Molecular characterization of a cloned human oxytocin receptor. Eur. J. Endocrinol., 131 (4): 385-90. [PMID:7921228]

54. Kimura T, Tanizawa O, Mori K, Brownstein MJ, Okayama H. (1992) Structure and expression of a human oxytocin receptor. Nature, 356 (6369): 526-9. [PMID:1313946]

55. Kubota Y, Kimura T, Hashimoto K, Tokugawa Y, Nobunaga K, Azuma C, Saji F, Murata Y. (1996) Structure and expression of the mouse oxytocin receptor gene. Mol. Cell. Endocrinol., 124 (1-2): 25-32. [PMID:9027321]

56. Lemaire W, O'Brien JA, Burno M, Chaudhary AG, Dean DC, Williams PD, Freidinger RM, Pettibone DJ, Williams DL. (2002) A nonpeptide oxytocin receptor antagonist radioligand highly selective for human receptors. Eur. J. Pharmacol., 450 (1): 19-28. [PMID:12176104]

57. Liu CX, Takahashi S, Murata T, Hashimoto K, Agatsuma T, Matsukawa S, Higuchi T. (1996) Changes in oxytocin receptor mRNA in the rat uterus measured by competitive reverse transcription-polymerase chain reaction. J. Endocrinol., 150 (3): 479-86. [PMID:8882167]

58. Loichot C, Grima M, De Jong W, Helwig JJ, Imbs JL, Barthelmebs M. (2002) Oxytocin-induced renin secretion by denervated kidney in anaesthetized rat. Eur. J. Pharmacol., 454 (2-3): 241-7. [PMID:12421653]

59. Loup F, Tribollet E, Dubois-Dauphin M, Pizzolato G, Dreifuss JJ. (1989) Localization of oxytocin binding sites in the human brainstem and upper spinal cord: an autoradiographic study. Brain Res., 500 (1-2): 223-30. [PMID:2557960]

60. Manning M, Cheng LL, Stoev S, Wo NC, Chan WY, Szeto HH, Durroux T, Mouillac B, Barberis C. (2005) Design of peptide oxytocin antagonists with strikingly higher affinities and selectivities for the human oxytocin receptor than atosiban. J. Pept. Sci., 11 (10): 593-608. [PMID:15880385]

61. McCafferty GP, Pullen MA, Wu C, Edwards RM, Allen MJ, Woollard PM, Borthwick AD, Liddle J, Hickey DM, Brooks DP et al.. (2007) Use of a novel and highly selective oxytocin receptor antagonist to characterize uterine contractions in the rat. Am. J. Physiol. Regul. Integr. Comp. Physiol., 293 (1): R299-305. [PMID:17395790]

62. Michelini S, Urbanek M, Dean M, Goldman D. (1995) Polymorphism and genetic mapping of the human oxytocin receptor gene on chromosome 3. Am J Med Genet, 60: 183-187. [PMID:7573168]

63. Neumann ID, Wigger A, Torner L, Holsboer F, Landgraf R. (2000) Brain oxytocin inhibits basal and stress-induced activity of the hypothalamo-pituitary-adrenal axis in male and female rats: partial action within the paraventricular nucleus. J. Neuroendocrinol., 12 (3): 235-43. [PMID:10718919]

64. Nishimori K, Young LJ, Guo Q, Wang Z, Insel TR, Matzuk MM. (1996) Oxytocin is required for nursing but is not essential for parturition or reproductive behavior. Proc. Natl. Acad. Sci. U.S.A., 93 (21): 11699-704. [PMID:8876199]

65. Olson BR, Drutarosky MD, Chow MS, Hruby VJ, Stricker EM, Verbalis JG. (1991) Oxytocin and an oxytocin agonist administered centrally decrease food intake in rats. Peptides, 12 (1): 113-8. [PMID:1646995]

66. Onaka T, Ikeda K, Yamashita T, Honda K. (2003) Facilitative role of endogenous oxytocin in noradrenaline release in the rat supraoptic nucleus. Eur. J. Neurosci., 18 (11): 3018-26. [PMID:14656297]

67. Ostrowski NL. (1998) Oxytocin receptor mRNA expression in rat brain: implications for behavioral integration and reproductive success. Psychoneuroendocrinology, 23 (8): 989-1004. [PMID:9924748]

68. Ostrowski NL, Lolait SJ. (1995) Oxytocin receptor gene expression in female rat kidney. The effect of estrogen. Adv. Exp. Med. Biol., 395: 329-40. [PMID:8713983]

69. Pena A, Murat B, Trueba M, Ventura MA, Wo NC, Szeto HH, Cheng LL, Stoev S, Guillon G, Manning M. (2007) Design and synthesis of the first selective agonists for the rat vasopressin V(1b) receptor: based on modifications of deamino-[Cys1]arginine vasopressin at positions 4 and 8. J Med Chem, 50: 835-847. [PMID:17300166]

70. Pettibone DJ, Woyden CJ, Totaro JA. (1990) Identification of functional oxytocin receptors in lactating rat mammary gland in vitro. Eur. J. Pharmacol., 188 (4-5): 235-41. [PMID:2163875]

71. Pierzynski P, Lemancewicz A, Reinheimer T, Akerlund M, Laudanski T. (2004) Inhibitory effect of barusiban and atosiban on oxytocin-induced contractions of myometrium from preterm and term pregnant women. J. Soc. Gynecol. Investig., 11 (6): 384-7. [PMID:15350251]

72. Quattropani A, Dorbais J, Covini D, Pittet PA, Colovray V, Thomas RJ, Coxhead R, Halazy S, Scheer A, Missotten M et al.. (2005) Discovery and development of a new class of potent, selective, orally active oxytocin receptor antagonists. J. Med. Chem., 48 (24): 7882-905. [PMID:16302826]

73. Randolph GW, Fuchs AR. (1989) Pulsatile administration enhances the effect and reduces the dose of oxytocin required for induction of labor. Am J Perinatol, 6 (2): 159-66. [PMID:2712912]

74. Ratni H, Rogers-Evans M, Bissantz C, Grundschober C, Moreau JL, Schuler F, Fischer H, Alvarez Sanchez R, Schnider P. (2015) Discovery of highly selective brain-penetrant vasopressin 1a antagonists for the potential treatment of autism via a chemogenomic and scaffold hopping approach. J. Med. Chem., 58 (5): 2275-89. [PMID:25654260]

75. Robinson DA, Wei F, Wang GD, Li P, Kim SJ, Vogt SK, Muglia LJ, Zhuo M. (2002) Oxytocin mediates stress-induced analgesia in adult mice. J Physiol, 540: 593-606. [PMID:11956346]

76. Rozen F, Russo C, Banville D, Zingg HH. (1995) Structure, characterization, and expression of the rat oxytocin receptor gene. Proc. Natl. Acad. Sci. U.S.A., 92 (1): 200-4. [PMID:7816817]

77. Schnider P, Bissantz C, Bruns A, Dolente C, Goetschi E, Jakob-Roetne R, Künnecke B, Mueggler T, Muster W, Parrott N et al.. (2020) Discovery of Balovaptan, a Vasopressin 1a Receptor Antagonist for the Treatment of Autism Spectrum Disorder. J. Med. Chem., 63 (4): 1511-1525. [PMID:31951127]

78. Serradeil-Le Gal C, Valette G, Foulon L, Germain G, Advenier C, Naline E, Bardou M, Martinolle J-P, Pouzet B, Raufaste D, Garcia C, Double-Cazenave E, Pauly M, Pascal M, Barbier A, Scatton B, Maffrand J-P, Le Fur G. (2004) SSR126768A (4-Chloro-3-[(3R)-(+)-5-chloro-1-(2,4-dimethoxybenzyl)-3-methyl-2oxo-2,3-dihydro-1H-indol-3-yl]-N-ethyl-N-(3-pyridylmethyl)-benzamidine, hydrochloride): a new selective and orally active oxytocin receptor antagonist for the prevention of preterm labor. J Pharmacol Exp Therap, 309: 414-424. [PMID:14722330]

79. Serradeil-Le Gal C, Wagnon J, Simiand J, Griebel G, Lacour C, Guillon G, Barberis C, Brossard G, Soubrie P, Nisato D, Pascal M, Pruss R, Scatton B, Maffrand JP, Le Fur G. (2002) Characterization of (2S,4R)-1-[5-chloro-1-[(2,4-dimethoxyphenyl)sulfonyl]-3-(2-methoxy-phenyl)-2-oxo-2,3-dihydro-1H-indol-3-yl]-4-hydroxy-N,N-dimethyl-2-pyrrolidine carboxamide (SSR149415), a selective and orally active vasopressin V1b receptor antagonist. J Pharmacol Exp Ther, 300: 1122-1130. [PMID:11861823]

80. Sjöquist M, Huang W, Jacobsson E, Skøtt O, Stricker EM, Sved AF. (1999) Sodium excretion and renin secretion after continuous versus pulsatile infusion of oxytocin in rats. Endocrinology, 140 (6): 2814-8. [PMID:10342872]

81. Soloff MS, Jeng YJ, Copland JA, Strakova Z, Hoare S. (2000) Signal pathways mediating oxytocin stimulation of prostaglandin synthesis in select target cells. Exp. Physiol., 85 Spec No: 51S-58S. [PMID:10795906]

82. Soloff MS, Wieder MH. (1983) Oxytocin receptors in rat involuting mammary gland. Can. J. Biochem. Cell Biol., 61 (7): 631-5. [PMID:6313159]

83. Strakova Z, Copland JA, Lolait SJ, Soloff MS. (1998) ERK2 mediates oxytocin-stimulated PGE2 synthesis. Am. J. Physiol., 274 (4): E634-41. [PMID:9575824]

84. Strakova Z, Soloff MS. (1997) Coupling of oxytocin receptor to G proteins in rat myometrium during labor: Gi receptor interaction. Am. J. Physiol., 272 (5 Pt 1): E870-6. [PMID:9176188]

85. Takayanagi Y, Yoshida M, Bielsky IF, Ross HE, Kawamata M, Onaka T, Yanagisawa T, Kimura T, Matzuk MM, Young LJ et al.. (2005) Pervasive social deficits, but normal parturition, in oxytocin receptor-deficient mice. Proc. Natl. Acad. Sci. U.S.A., 102 (44): 16096-101. [PMID:16249339]

86. Terrillon S, Durroux T, Mouillac B, Breit A, Ayoub MA, Taulan M, Jockers R, Barberis C, Bouvier M. (2003) Oxytocin and vasopressin V1a and V2 receptors form constitutive homo- and heterodimers during biosynthesis. Mol. Endocrinol., 17 (4): 677-91. [PMID:12554793]

87. Thibonnier M, Conarty DM, Preston JA, Plesnicher CL, Dweik RA, Erzurum SC. (1999) Human vascular endothelial cells express oxytocin receptors. Endocrinology, 140 (3): 1301-9. [PMID:10067857]

88. Tribollet E, Charpak S, Schmidt A, Dubois-Dauphin M, Dreifuss JJ. (1989) Appearance and transient expression of oxytocin receptors in fetal, infant, and peripubertal rat brain studied by autoradiography and electrophysiology. J. Neurosci., 9 (5): 1764-73. [PMID:2542479]

89. Vaccari C, Lolait SJ, Ostrowski NL. (1998) Comparative distribution of vasopressin V1b and oxytocin receptor messenger ribonucleic acids in brain. Endocrinology, 139 (12): 5015-33. [PMID:9832441]

90. Vignozzi L, Filippi S, Luconi M, Morelli A, Mancina R, Marini M, Vannelli GB, Granchi S, Orlando C, Gelmini S et al.. (2004) Oxytocin receptor is expressed in the penis and mediates an estrogen-dependent smooth muscle contractility. Endocrinology, 145 (4): 1823-34. [PMID:14691010]

91. Vignozzi L, Vannelli GB, Morelli A, Mancina R, Marini M, Ferruzzi P, Crescioli C, Luconi M, Donati S, Fisher AD et al.. (2005) Identification, characterization and biological activity of oxytocin receptor in the developing human penis. Mol. Hum. Reprod., 11 (2): 99-106. [PMID:15591449]

92. Wilson RJ, Allen MJ, Nandi M, Giles H, Thornton S. (2001) Spontaneous contractions of myometrium from humans, non-human primate and rodents are sensitive to selective oxytocin receptor antagonism in vitro. BJOG, 108 (9): 960-6. [PMID:11563467]

93. Windle RJ, Shanks N, Lightman SL, Ingram CD. (1997) Central oxytocin administration reduces stress-induced corticosterone release and anxiety behavior in rats. Endocrinology, 138 (7): 2829-34. [PMID:9202224]

94. Young 3rd WS, Shepard E, Amico J, Hennighausen L, Wagner KU, LaMarca ME, McKinney C, Ginns EI. (1996) Deficiency in mouse oxytocin prevents milk ejection, but not fertility or parturition. J. Neuroendocrinol., 8 (11): 847-53. [PMID:8933362]

95. Zhang XH, Filippi S, Vignozzi L, Morelli A, Mancina R, Luconi M, Donati S, Marini M, Vannelli GB, Forti G, Maggi M. (2005) Identification, localization and functional in vitro and in vivo activity of oxytocin receptor in the rat penis. J Endocrinol, 184: 567-576. [PMID:15749815]


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