MDMA ('Ecstasy'), oxytocin and vasopressin modulate social preference in rats: a role for handling and oxytocin receptors
Abstract
In laboratory rats, peripheral administration of the neuropeptides oxytocin (OT) and vasopressin (AVP) induces similar prosocial effects (i.e. increased adjacent lying) to the party drug 3,4-methylenedioxymethamphetamine (MDMA), which are sensitive to vasopressin V 1A receptor (V 1A R) antagonism. Here, we employed a social preference paradigm to further compare the prosocial effects of OT, AVP and MDMA. We also investigated the possible involvement of the V 1A R and oxytocin receptor (OTR) in rodent social preference. The social preference paradigm measures investigation times towards an empty wire cage (presented for 4min) followed by an identical cage containing a novel rat (also presented for 4min). Social preference is defined as greater investigation time towards the inhabited cage than the empty cage. Results indicated that well-handled rats exhibited no social preference at baseline, while intraperitoneally injected MDMA (5mg/kg), OT (0.5mg/kg) and AVP (0.005mg/kg) increased social preference. However, this effect was primarily due to reduced investigation of the empty cage. In contrast, rats that received minimal prior handling displayed a social preference at baseline, while MDMA (5mg/kg), OT (0.5mg/kg) and AVP (0.005mg/kg) reduced investigation times towards both the empty and inhabited cages. Lower doses of MDMA, OT and AVP were ineffective. The OTR antagonist Compound 25 (C25, 5mg/kg), but not the V 1A R antagonist SR49059 (1mg/kg), reduced the baseline social preference seen in minimally-handled rats and prevented the social preference induced by OT and AVP (but not MDMA) in well-handled rats. Overall, these results further confirm prosocial actions of MDMA, OT and AVP, which are dependent on handling history. These findings also indicate that social preference is sensitive to OTR rather than V 1A R modulation.
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Both OT and AVP administered peripherally increase social investigation in male rats.
“Both OT and AVP administered peripherally also increase social investigation in male rats.”
From Cross-talk among oxytocin and arginine-vasopressin receptors: Relevance for basic and clinical studies of the brain and periphery (2018) · cites this paper as [49]
A selective OTR antagonist, but not a selective V1aR antagonist, inhibits OT- and AVP-induced increases in social investigation, suggesting that both peptides act through the OTR.
“Peripheral administration of a selective OTR antagonist, but not a selective V1aR antagonist, inhibits OT- and AVP-induced increases in social investigation suggesting that both peptides are acting through the OTR [49].”
From Cross-talk among oxytocin and arginine-vasopressin receptors: Relevance for basic and clinical studies of the brain and periphery (2018) · cites this paper as [49]
Cites
The oxytocin receptor system: structure, function, and regulation
Gimpl, G., & Fahrenholz, F. (2001) · Physiological Reviews · doi:10.1152/physrev.2001.81.2.629 · Cited by 3,089 · see citing works
The Pharmacology and Clinical Pharmacology of 3,4-Methylenedioxymethamphetamine (MDMA, “Ecstasy”)
Green, A. R., Mechan, A. O., Elliott, J. M., O’Shea, E., & Colado, M. I. (2003) · Pharmacological Reviews · doi:10.1124/pr.55.3.3 · Cited by 1,272 · see citing works
Neumann, I. D., & Landgraf, R. (2012) · Trends in Neurosciences · doi:10.1016/j.tins.2012.08.004 · Cited by 954 · see citing works
Oxytocin Infusion Reduces Repetitive Behaviors in Adults with Autistic and Asperger's Disorders
Hollander, E., Novotny, S., Hanratty, M., Yaffe, R., DeCaria, C. M., Aronowitz, B. R., & Mosovich, S. (2003) · Neuropsychopharmacology · doi:10.1038/sj.npp.1300021 · Cited by 689 · see citing works
Olff, M., Frijling, J. L., Kubzansky, L. D., Bradley, B., Ellenbogen, M. A., Cardoso, C., Bartz, J. A., Yee, J. R., & van Zuiden, M. (2013) · Psychoneuroendocrinology · doi:10.1016/j.psyneuen.2013.06.019 · Cited by 620 · see citing works
Williams, J. R., Insel, T. R., Harbaugh, C. R., & Carter, C. S. (1994) · Journal of Neuroendocrinology · doi:10.1111/j.1365-2826.1994.tb00579.x · Cited by 483 · see citing works
Oxytocin and Vasopressin Agonists and Antagonists as Research Tools and Potential Therapeutics
Manning, M., Misicka, A., Olma, A., Bankowski, K., Stoev, S., Chini, B., Durroux, T., Mouillac, B., Corbani, M., & Guillon, G. (2012) · Journal of Neuroendocrinology · doi:10.1111/j.1365-2826.2012.02303.x · Cited by 423 · see citing works
Lukas, M., Toth, I., Reber, S. O., Slattery, D. A., Veenema, A. H., & Neumann, I. D. (2011) · Neuropsychopharmacology · doi:10.1038/npp.2011.95 · Cited by 403 · see citing works
Ecstasy (MDMA): a review of its possible persistent psychological effects
Morgan, M. J. (2000) · Psychopharmacology · doi:10.1007/s002130000545 · Cited by 380 · see citing works
MDMA enhances emotional empathy and prosocial behavior
Hysek, C. M., Schmid, Y., Simmler, L. D., Domes, G., Heinrichs, M., Eisenegger, C., Preller, K. H., Quednow, B. B., & Liechti, M. E. (2014) · Social Cognitive and Affective Neuroscience · doi:10.1093/scan/nst161 · Cited by 356 · see citing works
Gal, C. S., Wagnon, J., Garcia, C., Lacour, C., Guiraudou, P., Christophe, B., Villanova, G., Nisato, D., Maffrand, J., & Fur, G. L. (1993) · Journal of Clinical Investigation · doi:10.1172/jci116554 · Cited by 272 · see citing works
Tickling induces reward in adolescent rats.
Burgdorf, J., & Panksepp, J. (2001) · Physiology & Behavior · doi:10.1016/s0031-9384(00)00411-x · Cited by 269 · see citing works
Breaking the loop: Oxytocin as a potential treatment for drug addiction
McGregor, I. S., & Bowen, M. T. (2012) · Hormones and Behavior · doi:10.1016/j.yhbeh.2011.12.001 · Cited by 268 · see citing works
Self-citationDumont, G. J. H., Sweep, F. C. G. J., van der Steen, R., Hermsen, R., Donders, A. R. T., Touw, D. J., van Gerven, J. M. A., Buitelaar, J. K., & Verkes, R. J. (2009) · Social Neuroscience · doi:10.1080/17470910802649470 · Cited by 238 · see citing works
Thompson, M. R., Callaghan, P. D., Hunt, G. E., Cornish, J. L., & McGregor, I. S. (2007) · Neuroscience · doi:10.1016/j.neuroscience.2007.02.032 · Cited by 237 · see citing works
Self-citationCrawley, J. N., Chen, T., Puri, A., Washburn, R., Sullivan, T. L., Hill, J. M., Young, N. B., Nadler, J. J., Moy, S. S., Young, L. J., et al. (2007) · Neuropeptides · doi:10.1016/j.npep.2007.02.002 · Cited by 232 · see citing works
UVNäS‐MOBERG, K., BRUZELIUS, G., ALSTER, P., & LUNDEBERG, T. (1993) · Acta Physiologica Scandinavica · doi:10.1111/j.1748-1716.1993.tb09612.x · Cited by 196 · see citing works
Oxytocin increases anxiety to unpredictable threat
Grillon, C., Krimsky, M., Charney, D. R., Vytal, K., Ernst, M., & Cornwell, B. (2013) · Molecular Psychiatry · doi:10.1038/mp.2012.156 · Cited by 192 · see citing works
Ribosomopathies: how a common root can cause a tree of pathologies
Danilova, N., & Gazda, H. T. (2015) · Disease Models & Mechanisms · doi:10.1242/dmm.020529 · Cited by 185 · see citing works
Schmitt, U., & Hiemke, C. (1998) · Pharmacology, Biochemistry and Behavior · doi:10.1016/s0091-3057(97)00502-9 · Cited by 175 · see citing works
Do initial responses to drugs predict future use or abuse?
de Wit, H., & Phillips, T. J. (2012) · Neuroscience & Biobehavioral Reviews · doi:10.1016/j.neubiorev.2012.04.005 · Cited by 172 · see citing works
Low-dose MDMA (“ecstasy”) induces vasopressin secretion
Henry, J. A., Fallon, J. K., Kicman, A. T., Hutt, A. J., Cowan, D., & Forsling, M. L. (1998) · The Lancet · doi:10.1016/s0140-6736(05)78744-4 · Cited by 171 · see citing works
Behavioural consequences of two chronic psychosocial stress paradigms: Anxiety without depression
Slattery, D. A., Uschold‐Schmidt, N., Magoni, M., Bär, J., Popoli, M., Neumann, I. D., & Reber, S. O. (2011) · Psychoneuroendocrinology · doi:10.1016/j.psyneuen.2011.09.002 · Cited by 129 · see citing works
Ramos, L., Hicks, C., Kevin, R., Caminer, A., Narlawar, R., Kassiou, M., & McGregor, I. S. (2013) · Neuropsychopharmacology · doi:10.1038/npp.2013.125 · Cited by 128 · see citing works
Self-citationThe involvement of the vasopressin system in stress-related disorders
Landgraf, R. (2006) · CNS & Neurological Disorders - Drug Targets · doi:10.2174/187152706776359664 · Cited by 127 · see citing works
(±)-3,4-Methylenedioxymethamphetamine (MDMA, ‘Ecstasy’) increases social interaction in rats
Morley, K. C., & McGregor, I. S. (2000) · European Journal of Pharmacology · doi:10.1016/s0014-2999(00)00749-4 · Cited by 111 · see citing works
Self-citationKelly, A. M., Kingsbury, M. A., Hoffbuhr, K., Schrock, S. E., Waxman, B., Kabelik, D., Thompson, R. R., & Goodson, J. L. (2011) · Hormones and Behavior · doi:10.1016/j.yhbeh.2011.01.012 · Cited by 106 · see citing works
MDMA alters emotional processing and facilitates positive social interaction
Wardle, M. C., & de Wit, H. (2014) · Psychopharmacology · doi:10.1007/s00213-014-3570-x · Cited by 96 · see citing works
Mak, P., Broussard, C., Vacy, K., & Broadbear, J. H. (2011) · Journal of Psychopharmacology · doi:10.1177/0269881111416687 · Cited by 95 · see citing works
Sex Differences in the Effects of MDMA (Ecstasy) on Plasma Copeptin in Healthy Subjects
Simmler, L. D., Hysek, C. M., & Liechti, M. E. (2011) · The Journal of Clinical Endocrinology & Metabolism · doi:10.1210/jc.2011-1143 · Cited by 89 · see citing works
Heat increases 3,4-methylenedioxymethamphetamine self-administration and social effects in rats
Cornish, J. L., Shahnawaz, Z., Thompson, M. R., Wong, S., Morley, K. C., Hunt, G. E., & McGregor, I. S. (2003) · European Journal of Pharmacology · doi:10.1016/j.ejphar.2003.09.060 · Cited by 83 · see citing works
Self-citationMorley, K. C., Arnold, J. C., & McGregor, I. S. (2005) · Progress in Neuro-Psychopharmacology and Biological Psychiatry · doi:10.1016/j.pnpbp.2005.04.009 · Cited by 79 · see citing works
Self-citationHicks, C., Jorgensen, W., Brown, C., Fardell, J., Koehbach, J., Gruber, C. W., Kassiou, M., Hunt, G. E., & McGregor, I. S. (2012) · Journal of Neuroendocrinology · doi:10.1111/j.1365-2826.2012.02311.x · Cited by 73 · see citing works
Self-citationBrown, A. D., Brown, T. B., Calabrese, A. A., Ellis, D. J., Puhalo, N., Ralph, M. J., & Watson, L. (2009) · Bioorganic & Medicinal Chemistry Letters · doi:10.1016/j.bmcl.2009.11.097 · Cited by 73 · see citing works
Oxytocin and vasopressin modulate the social response to threat: a preclinical study
Bowen, M. T., & McGregor, I. S. (2014) · The International Journal of Neuropsychopharmacology · doi:10.1017/s1461145714000388 · Cited by 63 · see citing works
Self-citationChronic Subordinate Colony Housing (CSC) as a Model of Chronic Psychosocial Stress in Male Rats
Nyuyki, K. D., Beiderbeck, D. I., Lukas, M., Neumann, I. D., & Reber, S. O. (2012) · PLoS ONE · doi:10.1371/journal.pone.0052371 · Cited by 55 · see citing works
Wardle, M. C., Kirkpatrick, M. G., & de Wit, H. (2014) · Social Cognitive and Affective Neuroscience · doi:10.1093/scan/nsu035 · Cited by 52 · see citing works
Hunt, G. E., McGregor, I. S., Cornish, J. L., & Callaghan, P. D. (2011) · Brain Research Bulletin · doi:10.1016/j.brainresbull.2011.06.011 · Cited by 51 · see citing works
Self-citationCalcagnoli, F., Meyer, N., de Boer, S. F., Althaus, M., & Koolhaas, J. M. (2014) · Hormones and Behavior · doi:10.1016/j.yhbeh.2014.03.008 · Cited by 49 · see citing works
Neural correlates of MDMA (“Ecstasy”)-induced social interaction in rats
Thompson, M. R., Hunt, G. E., & McGregor, I. S. (2008) · Social Neuroscience · doi:10.1080/17470910802045042 · Cited by 48 · see citing works
Self-citationAggregation in quads but not pairs of rats exposed to cat odor or bright light
Bowen, M. T., Keats, K., Kendig, M. D., Cakic, V., Callaghan, P. D., & McGregor, I. S. (2012) · Behavioural Processes · doi:10.1016/j.beproc.2012.03.014 · Cited by 40 · see citing works
Self-citationCharles, R., Sakurai, T., Takahashi, N., Elder, G. A., Sosa, M. A. G., Young, L. J., & Buxbaum, J. D. (2014) · Disease Models & Mechanisms · doi:10.1242/dmm.017053 · Cited by 23 · see citing works
Inhaled vasopressin increases sociability and reduces body temperature and heart rate in rats
Ramos, L., Hicks, C., Caminer, A., & McGregor, I. S. (2014) · Psychoneuroendocrinology · doi:10.1016/j.psyneuen.2014.04.013 · Cited by 21 · see citing works
Self-citationThe effect of handling rats on their growth and behaviour
Cowley, J. J., & Widdowson, E. M. (1965) · British Journal Of Nutrition · doi:10.1079/bjn19650037 · Cited by 19 · see citing works
Amodeo, M., Peou, S., Grigg-Saito, D. C., Berke, H., Pin-Riebe, S., & Jones, L. K. (2004) · Journal of Social Work Practice in the Addictions · doi:10.1300/j160v04n03_03 · Cited by 15 · see citing works
Oxytocin and object preferences in the male prairie vole
Madularu, D., Athanassiou, M., Yee, J. R., Kenkel, W. M., Carter, C. S., & Mumby, D. G. (2014) · Peptides · doi:10.1016/j.peptides.2014.08.015 · Cited by 10 · see citing works
Methamphetamine and MDMA Neurotoxicity: Biochemical and Molecular Mechanisms
Bisagno, V., & Cadet, J. L. (2021) · Springer eBooks · doi:10.1007/978-3-030-71519-9_80-1 · Cited by 8 · see citing works
Methamphetamine and MDMA Neurotoxicity: Biochemical and Molecular Mechanisms
Bisagno, V., & Cadet, J. L. (2014) · Springer eBooks · doi:10.1007/978-1-4614-5836-4_80 · Cited by 5 · see citing works
Male Scent May Compromise Biomedical Studies
Grimm, D. (2014) · Science · doi:10.1126/science.344.6183.461 · Cited by 4 · see citing works
What All Social Workers Should Know About MDMA (Ecstasy)
Harris, G. (2004) · Journal of Social Work Practice in the Addictions · doi:10.1300/j160v04n01_03 · Cited by 2 · see citing works
Flagged first, then by citations
1 of the 51 references couldn’t be matched to a known paper.
Cited by
Sorted by citations
Gregorio, D. D., Aguilar‐Valles, A., Preller, K. H., Heifets, B. D., Hibicke, M., Mitchell, J., & Gobbi, G. (2020) · Journal of Neuroscience · doi:10.1523/jneurosci.1659-20.2020 · Cited by 261 · see citing works
Song, Z., & Albers, H. E. (2018) · Frontiers in Neuroendocrinology · doi:10.1016/j.yfrne.2017.10.004 · Cited by 244 · see citing works
The Psychedelic Future of Post-Traumatic Stress Disorder Treatment
Zaretsky, T. G., Jagodnik, K. M., Barsic, R., Antonio, J. H., Bonanno, P. A., MacLeod, C., Pierce, C., Carney, H., Morrison, M. T., Saylor, C. F., et al. (2024) · Current Neuropharmacology · doi:10.2174/1570159x22666231027111147 · Cited by 85 · see citing works
Therapeutic mechanisms of psychedelics and entactogens
Heifets, B. D., & Olson, D. E. (2023) · Neuropsychopharmacology · doi:10.1038/s41386-023-01666-5 · Cited by 67 · see citing works
Vizeli, P., & Liechti, M. E. (2018) · PLoS ONE · doi:10.1371/journal.pone.0199384 · Cited by 36 · see citing works
GRK2/β‐arrestin mediates arginine vasopressin‐induced cardiac fibroblast proliferation
Chen, Y., Xu, F., Zhang, L., Wang, X., Wang, Y., Woo, A. Y., & Zhu, W. (2016) · Clinical and Experimental Pharmacology and Physiology · doi:10.1111/1440-1681.12696 · Cited by 25 · see citing works
Xu, F., Sun, S., Wang, X., Ni, E., Zhao, L., & Zhu, W. (2017) · Molecular Pharmacology · doi:10.1124/mol.116.107698 · Cited by 23 · see citing works
Lyu, L. K., Li, J. S., Wang, X. J., Yao, Y. J., Li, J. F., Li, Y., Wen, H. S., & Qi, X. (2021) · Frontiers in Endocrinology · doi:10.3389/fendo.2021.617580 · Cited by 20 · see citing works
Avgana, H., Toledano, R. S., & Akirav, I. (2024) · Pharmaceuticals · doi:10.3390/ph17070846 · Cited by 11 · see citing works
Johne, M., Helgers, S. O. A., Alam, M., Jelinek, J., Hubka, P., Krauss, J. K., Scheper, V., Kral, A., & Schwabe, K. (2022) · Frontiers in Neuroscience · doi:10.3389/fnins.2022.966568 · Cited by 11 · see citing works
A Systematic Review of the MDMA Model to Address Social Impairment in Autism
Chaliha, D. R., Mamo, J. C. L., Albrecht, M. A., Lam, V., Takechi, R., & Vaccarezza, M. (2021) · Current Neuropharmacology · doi:10.2174/1570159x19666210101130258 · Cited by 7 · see citing works
Naloxone increases conditioned fear responses during social buffering in male rats
Yamasaki, T., Kiyokawa, Y., Munetomo, A., & Takeuchi, Y. (2024) · European Journal of Neuroscience · doi:10.1111/ejn.16343 · Cited by 7 · see citing works
Román, V., Kedves, R., Kelemen, K., Némethy, Z., Sperlágh, B., Lendvai, B., & Vizi, E. S. (2021) · Physiological Reports · doi:10.14814/phy2.15088 · Cited by 7 · see citing works
Neurotransmitters and Hormones in Human Decision-Making
Rivera, L. F. S., & Gouvêia, A. (2021) · Springer eBooks · doi:10.1007/978-3-030-61721-9_15 · Cited by 6 · see citing works
Dolder, P. C., Perna, E. B. D. S. F., Mason, N. L., Hutten, N. R. P. W., Toennes, S. W., Theunissen, E. L., Ramaekers, J. G., & Kuypers, K. P. C. (2018) · Human Psychopharmacology Clinical and Experimental · doi:10.1002/hup.2680 · Cited by 6 · see citing works
History, pharmacology and therapeutic mechanisms of 3,4‐methylenedioxymethamphetamine (MDMA)
Casey, A. B., & Heifets, B. D. (2025) · British Journal of Pharmacology · doi:10.1111/bph.70225 · Cited by 4 · see citing works
Maciąg, M., Doszyn, O., Wnorowski, A., Zmorzyńska, J., & Budzyńska, B. (2025) · Journal of Psychopharmacology · doi:10.1177/02698811251324596 · Cited by 4 · see citing works
The psychedelic-peptide paradox: a hormetic hypothesis
Carter, C. S. (2025) · Comprehensive Psychoneuroendocrinology · doi:10.1016/j.cpnec.2025.100303 · Cited by 4 · see citing works
Sampedro-Viana, D., Cañete, T., Ancil-Gascón, P., Cisci, S., Tobeña, A., & Fernández‐Teruel, A. (2024) · Brain Sciences · doi:10.3390/brainsci14090920 · Cited by 3 · see citing works
Kareklas, K., Sorigue, P., & Oliveira, R. F. (2025) · Masterclass in neuroendocrinology · doi:10.1007/978-3-031-80209-6_15 · Cited by 3 · see citing works
Palacios-Lagunas, D. A., Hernández-Mondragón, J. C., Fuxé, K., Borroto‐Escuela, D. O., Crespo‐Ramírez, M., Pérez-Eugenio, F., & de la Mora, M. P. (2025) · Pharmacology Biochemistry and Behavior · doi:10.1016/j.pbb.2025.174135 · Cited by 1 · see citing works
Thomas, J. E., Dellarole, A., & Caballero, J. (2026) · American Journal of Health-System Pharmacy · doi:10.1093/ajhp/zxag062 · Cited by 2 · see citing works
Naloxone blocks social buffering of conditioned fear responses in ratsPreprint
Yamasaki, T., Kiyokawa, Y., Munetomo, A., & Takeuchi, Y. (2023) · doi:10.22541/au.168434829.95000136/v1
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Abedpour, N., Fard, A. A., Rahimi, P., & Javanmard, M. Z. (2023) · doi:10.32592/jsmj.22.3.290
Attenuating neuropsychiatric disorders of early-life stress: The protective role of oxytocin
Zhang, Y., Wang, S., & Hei, M. (2026) · World Journal of Psychiatry · doi:10.5498/wjp.v16.i4.115109
- Authors
- Ramos, L., Hicks, C., Caminer, A., Couto, K., Narlawar, R., Kassiou, M., & McGregor, I. S.
- Affiliations
- The University of Sydney (AU)
- Corresponding author
- McGregor, Iain S.
- Venue
- Pharmacology Biochemistry and Behavior
- Publisher
- Elsevier BV
- Published
- 2016-11
- Volume
- 150-151
- Pages
- 115-123
- ISSN
- 0091-3057 (ISSN-L)
- OpenAlex
- W2531655104
- Cited by
- 25
- References
- 51
- Citations by year
- 2026: 2 · 2025: 5 · 2024: 4 · 2023: 3 · 2022: 1 · 2021: 4 · 2020: 1 · 2018: 2 · 2017: 2 · 2016: 1
- FWCI
- 2.63
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Pharmacology Biochemistry and Behavior (publishedVersion)
- PubMed (publishedVersion)
- Topics
- Social Sciences › Psychology › Social Psychology › Neuroendocrine regulation and behavior
- Life Sciences › Neuroscience › Cellular and Molecular Neuroscience › Neurotransmitter Receptor Influence on Behavior
- Social Sciences › Psychology › Clinical Psychology › Psychedelics and Drug Studies
- Keywords
- MDMA, ecstasy, oxytocin, vasopressin, social preferences, prosocial behavior, oxytocin receptor, vasopressin V1a receptor, neuropeptides, rats
- MeSH terms
- Animals, Animal Husbandry, Indoles, Male, Oxytocin, Pyrrolidines, Social Behavior, Vasopressins, Receptors, Vasopressin, Receptors, Oxytocin, N-Methyl-3,4-methylenedioxyamphetamine, Rats, Long-Evans, Rats
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