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Horn AJ, Cole S, Nazarloo HP, Nazarloo P, Davis JM, Carrier D, Bryan C, Carter CS. Severe PTSD is marked by reduced oxytocin and elevated vasopressin. COMPREHENSIVE PSYCHONEUROENDOCRINOLOGY 2024; 19:100236. [PMID: 38764609 PMCID: PMC11101686 DOI: 10.1016/j.cpnec.2024.100236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 04/17/2024] [Accepted: 04/21/2024] [Indexed: 05/21/2024] Open
Abstract
Neuroendocrine analyses of posttraumatic stress disorder (PTSD) have generally focused on hypothalamic-pituitary-adrenal (HPA) axis alterations. In the present analyses, we examine two additional neuroendocrine factors that have been previously implicated in biological stress responses: oxytocin (OT) and arginine vasopressin (AVP). Here we examined basal neuropeptide status in military veterans clinically diagnosed with PTSD (n = 29) and in two non-traumatized comparison groups with previous stress exposure (n = 11 SWAT trainees and n = 21 ultramarathon runners). PTSD patients showed low levels of plasma OT and high levels of AVP. The ratio of AVP/OT robustly related to PTSD status, and emerged as a statistically plausible mediator of relationships between the number of personal traumatic experiences and subsequent PTSD symptom burden. Over the course of behavioral therapy for PTSD, measures of OT showed a significant but modest normalization. Plasma cortisol levels were not statistically different among the three groups. This study suggests that AVP/OT ratios may represent a neuroendocrine predictor of severe PTSD, as well as a potential treatment response biomarker.
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Affiliation(s)
| | - Steve Cole
- UCLA School of Medicine, Department of Psychiatry & Biobehavioral Sciences, Los Angeles, CA, USA
| | | | | | - John M. Davis
- Department of Psychiatry, University of Illinois at Chicago, Chicago, IL, USA
| | - David Carrier
- Department of Biology, University of Utah, Salt Lake City, UT, USA
| | - Craig Bryan
- Department of Psychiatry and Behavioral Health, The Ohio State University, Columbus, OH, USA
| | - C. Sue Carter
- Kinsey Institute, Indiana University, Bloomington, IN, USA
- Department of Psychology, University of Virginia, Charlottesville, VA, USA
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Coté JJ, Coté RD, Dilsaver DB, Stessman HAF, Watson C, Handelzalts J, Doehrman P, Walters RW, Badura-Brack AS. Human placental lactogen (human chorionic somatomammotropin) and oxytocin during pregnancy: Individual patterns and associations with maternal-fetal attachment, anxiety, and depression. Horm Behav 2024; 163:105560. [PMID: 38723407 DOI: 10.1016/j.yhbeh.2024.105560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 02/29/2024] [Accepted: 05/01/2024] [Indexed: 06/17/2024]
Abstract
Previous studies support links among maternal-fetal attachment, psychological symptoms, and hormones during pregnancy and the post-partum period. Other studies connect maternal feelings and behaviors to oxytocin and suggest that an increase in oxytocin during pregnancy may prime maternal-fetal attachment. To date, researchers have not examined a possible association between maternal-fetal attachment with human placental lactogen although animal models are suggestive. In the current study, we sought to describe oxytocin and human placental lactogen levels as related to psychological constructs across pregnancy. Seventy women participated in the study. At each of three time-points (early, mid, and late pregnancy), the women had their blood drawn to assess oxytocin and human placental lactogen levels, and they completed psychological assessments measuring maternal-fetal attachment, anxiety, and depression. Our results indicate that oxytocin levels were statistically similar across pregnancy, but that human placental lactogen significantly increased across pregnancy. Results did not indicate significant associations of within-person (comparing individuals to themselves) oxytocin or human placental lactogen levels with maternal-fetal attachment. Additionally, results did not show between-person (comparing individuals to other individuals) oxytocin or human placental lactogen levels with maternal-fetal attachment. Oxytocin levels were not associated with anxiety; rather the stage of pregnancy moderated the effect of the within-person OT level on depression. Notably, increasing levels of human placental lactogen were significantly associated with increasing levels of both anxiety and depression in between subject analyses. The current study is important because it describes typical hormonal and maternal fetal attachment levels during each stage of pregnancy, and because it suggests an association between human placental lactogen and psychological symptoms during pregnancy. Future research should further elucidate these relationships.
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Affiliation(s)
- John J Coté
- Department of Obstetrics and Gynecology, Creighton University School of Medicine, Omaha, NE, USA; Department of Obstetrics and Gynecology, CommonSpirit/CHI Health, Lakeside, Omaha, NE, USA.
| | | | - Danielle B Dilsaver
- Department of Clinical Research and Public Health, Creighton University School of Medicine, Omaha, NE, USA
| | - Holly A F Stessman
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, USA
| | - Cynthia Watson
- Biorepository Core, Creighton University School of Medicine, USA
| | - Jonathan Handelzalts
- The Academic College of Tel-Aviv, Graduate Program in Clinical Psychology, School of Behavioral Sciences, Yaffo, Israel; Department of Psychiatry, University of Michigan, Ann Arbor, MI, USA
| | - Pooja Doehrman
- Department of Obstetrics and Gynecology, Creighton University School of Medicine, Phoenix, AZ 85013, USA; Department of Obstetrics and Gynecology, University of Arizona College of Medicine, Phoenix, AZ 85013, USA; Department of Obstetrics and Gynecology CommonSpirit/Dignity Health, Phoenix, AZ, USA
| | - Ryan W Walters
- Department of Clinical Research and Public Health, Creighton University School of Medicine, Omaha, NE, USA
| | - Amy S Badura-Brack
- Department of Psychological Science, Creighton University, Omaha, NE, USA
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3
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Conklin QA, Zanesco AP, King BG, Epel ES, Saron CD. Changes in peripheral oxytocin and vasopressin during a silent month-long Insight meditation retreat. Front Endocrinol (Lausanne) 2024; 15:1345527. [PMID: 38863930 PMCID: PMC11165068 DOI: 10.3389/fendo.2024.1345527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 04/30/2024] [Indexed: 06/13/2024] Open
Abstract
Background Given its putative roles in mediating prosocial behavior, attachment bonds, and stress physiology, oxytocin modulation has been hypothesized to be a biological correlate of the salubrious effects of meditation practice. Here we investigated the effects of a month-long silent meditation retreat on changes in oxytocin, and the related hormone and vasopressin, in relation to psychosocial changes in attachment style, anxiety, personality measures, and feelings of social connectedness with fellow meditators. Methods Plasma oxytocin and vasopressin and self-report questionnaires were measured in retreat participants (n = 28) at the beginning of, and 3 weeks into, a residential meditation retreat. Control participants (n = 34), who were similar in age, gender, and meditation experience, were also assessed across a 3-week interval. Linear mixed effects models were used to assess outcomes. Results The retreat group showed a small but significant decrease in oxytocin compared to controls who showed no change. In the retreat group, higher openness to experience at Time 1 predicted greater reductions in oxytocin during the retreat, and lower oxytocin at Time 2 was related to stronger feelings of personal connection with fellow meditators. The changes in oxytocin were not related to attachment style or anxiety. Vasopressin decreased over time across both groups, suggesting no specific effect of retreat. Conclusion These preliminary findings suggest that meditation training in the context of a silent residential retreat may reduce circulating levels of oxytocin. We interpret this finding from multiple theoretical perspectives, discussing key measurement limitations and proposing future study designs that may help to differentiate the effects of different meditation practices and contexts on oxytocin signaling.
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Affiliation(s)
- Quinn A. Conklin
- Center for Health and Community, University of California, San Francisco, San Francisco, CA, United States
- Center for Mind and Brain, University of California, Davis, Davis, CA, United States
| | - Anthony P. Zanesco
- Center for Mind and Brain, University of California, Davis, Davis, CA, United States
- Department of Psychology, University of Miami, Miami, FL, United States
| | - Brandon G. King
- Center for Mind and Brain, University of California, Davis, Davis, CA, United States
| | - Elissa S. Epel
- Center for Health and Community, University of California, San Francisco, San Francisco, CA, United States
- Department of Psychiatry, University of California, San Francisco, San Francisco, CA, United States
| | - Clifford D. Saron
- Center for Mind and Brain, University of California, Davis, Davis, CA, United States
- The MIND Institute, University of California, Davis, Davis, CA, United States
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Moscovice LR, Sobczak B, Niittynen T, Koski SE, Gimsa U. Changes in salivary oxytocin in response to biologically-relevant events in farm animals: method optimization and usefulness as a biomarker. Front Physiol 2024; 15:1370557. [PMID: 38567114 PMCID: PMC10985263 DOI: 10.3389/fphys.2024.1370557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Accepted: 02/21/2024] [Indexed: 04/04/2024] Open
Abstract
Although best known for its established role in mediating parturition and lactation, the highly-conserved neuropeptide hormone oxytocin also mediates a range of social and stress-buffering processes across mammalian species. Measurements of peripheral oxytocin in plasma have long been considered the gold standard, but there is increasing interest in developing methods to detect oxytocin non-invasively in saliva. Here we present an analytical and biological validation of a novel method to measure salivary oxytocin (sOXT) in an under-studied research group: farm animals. Given their similarities with humans in physiology and brain, methods that can identify valued social contexts and social relationships for farm animals and investigate their function have implications for clinical research as well as for animal welfare science. However, current methods to measure sOXT vary greatly in terms of sample collection, pre-measurement processing and measurement and more rigorous standardization and validation of methods is critical to determine the utility of sOXT as a biomarker of salient social events and related emotions. We optimized a method for extracting sOXT in pigs and horses and measured sOXT in extracted samples using a commercially available enzyme-immunoassay. Extracted samples were within acceptable ranges for precision (CVs < 15.2%), parallelism and recovery (94%-99%) in both species. Salivary oxytocin increased in samples collected during birth in pigs (Friedmans, p = 0.02) and horses (Wilcoxon, p = 0.02). Salivary oxytocin tended to decrease in sows after a 90-min separation from their piglets (Wilcoxon, p = 0.08). We conclude that sOXT can be reliably linked to physiological events that are mediated by the oxytocinergic system in farm animals, but that more research is needed to determine whether sOXT is a reliable trait marker for more general oxytocin system activation in response to salient social events. Future research should characterize how individual attributes and salivary parameters influence sOXT measurement and should emphasize reporting of analytical and biological validations to increase acceptance of non-invasive methods.
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Affiliation(s)
- Liza R. Moscovice
- Psychophysiology Working Group, Research Institute for Farm Animal Biology, Dummerstorf, Germany
| | - Birgit Sobczak
- Psychophysiology Working Group, Research Institute for Farm Animal Biology, Dummerstorf, Germany
| | - Taru Niittynen
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, Helsinki, Finland
| | - Sonja E. Koski
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, Helsinki, Finland
| | - Ulrike Gimsa
- Psychophysiology Working Group, Research Institute for Farm Animal Biology, Dummerstorf, Germany
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MacLean EL, Carranza E, Gnanadesikan GE, King KM, Allen AM, Linde-Krieger LB, Feldman R, White-Traut RC, Hammock EAD, Carter CS, Leng G, Tecot SR, Bell AF. Neurophysin I is an analytically robust surrogate biomarker for oxytocin. Psychoneuroendocrinology 2024; 161:106951. [PMID: 38194845 PMCID: PMC10872509 DOI: 10.1016/j.psyneuen.2023.106951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 12/27/2023] [Accepted: 12/29/2023] [Indexed: 01/11/2024]
Abstract
Oxytocin is a pleiotropic neuropeptide that plays roles in biological processes ranging from birth, lactation, and social bonding to immune function, cardiovascular repair, and regulation of appetite. Although measurements of endogenous oxytocin concentrations have been performed for more than 50 years, the ability to measure oxytocin accurately poses notable challenges. One potential solution for overcoming these challenges involves measurement of oxytocin's carrier molecule - neurophysin I (NP-1) - as a surrogate biomarker. NP-1 is secreted in equimolar concentrations with oxytocin but has a longer half-life, circulates in higher concentrations, and can be measured using a sandwich immunoassay. We report experiments that 1) analytically validate a commercially available NP-1 sandwich immunoassay for use with human plasma and urine samples, 2) confirm the specificity of this assay, based on detection of NP-1 in plasma from wild-type but not oxytocin knockout mice, 3) demonstrate that NP-1 concentrations are markedly elevated in late pregnancy, consistent with studies showing substantial increases in plasma oxytocin throughout gestation, and 4) establish strong correlation between NP-1 and plasma oxytocin concentrations when oxytocin is measured in extracted (but not non-extracted) plasma. The NP-1 assay used in this study has strong analytical properties, does not require time-intensive extraction protocols, and the assay itself can be completed in < 2 h (compared to 16-24 h for a competitive oxytocin immunoassay). Our findings suggest that much like copeptin has become a useful surrogate biomarker in studies of vasopressin, measurements of NP-1 have similar potential to advance oxytocin research.
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Affiliation(s)
- Evan L MacLean
- College of Veterinary Medicine, University of Arizona, Tucson, AZ, USA; Department of Psychology, University of Arizona, Tucson, AZ, USA.
| | | | | | | | - Alicia M Allen
- Department of Family and Community Medicine, University of Arizona, Tucson, AZ, USA
| | | | - Ruth Feldman
- Center for Developmental Social Neuroscience, Reichman University, Israel; Yale Child Study Center, Yale University, New Haven, CT, USA
| | - Rosemary C White-Traut
- Children's Research Institute, Children's Wisconsin, Milwaukee, WI, USA; Department of Human Development Nursing Science, University of Illinois, Chicago, IL, USA
| | | | - C Sue Carter
- Kinsey Institute, Indiana University, Bloomington, IN, USA; Department of Psychology, University of Virginia, Charlottesville, VA, USA
| | - Gareth Leng
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Stacey R Tecot
- School of Anthropology, University of Arizona, Tucson, AZ, USA; Laboratory for the Evolutionary Endocrinology of Primates, University of Arizona, Tucson, AZ, USA
| | - Aleeca F Bell
- College of Nursing, University of Arizona, Tucson, AZ, USA
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Zagoory-Sharon O, Levine A, Feldman R. Human sweat contains oxytocin. Psychoneuroendocrinology 2023; 158:106407. [PMID: 37797406 DOI: 10.1016/j.psyneuen.2023.106407] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Revised: 08/20/2023] [Accepted: 09/23/2023] [Indexed: 10/07/2023]
Abstract
BACKGROUND Oxytocin (OT) has been detected in various body fluids, including blood, urine, saliva, breastmilk, and spinal fluid. Consistent with models that regard skin as a social organ and in line with studies demonstrating that skin cells express both OT and its receptor, our study sought to examine the presence of OT in human sweat. METHODS Overall, 553 individuals participated in a pilot study and three experiments. Firstly, 50 participants provided sweat after engaging in various sports for different durations. Secondly, 26 participants provided sweat from forehead, upper-chest, forearm, and underarm, including 11 in natural setting and 15 following OT administration and a 30-minute exercise. Thirdly, of 435 volunteers, 97 provided sufficient axillary sweat for assaying. Of these, 84 participated in a naturalistic experiment that involved saliva and sweat collection in response to physical activity in either solitary or social settings. OT and testosterone (TS) were assayed in sweat and saliva. RESULTS Intense activity for at least 25 min was required to produce sufficient sweat for OT analysis. Highest OT levels were found in axillary sweat compared to sweat from the forehead, upper-chest, and forearm. Salivary OT and TS increased after both solitary and social physical activity; however, higher sweat OT was found after solitary sports. Post-hoc preliminary findings indicate that highly extroverted individuals exercising in solitary environments showed the highest sweat OT levels. CONCLUSIONS Findings demonstrate, for the first time, the presence of OT in human sweat and show the feasibility of its measurement. Much further research is required to illuminate how sweat OT is impacted by personality and social context and to uncover the role of the skin in OT production.
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Affiliation(s)
| | - Ari Levine
- Center for Developmental Social Neuroscience, Reichman University, Israel
| | - Ruth Feldman
- Center for Developmental Social Neuroscience, Reichman University, Israel
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Carter CS. Close encounters with oxytocin. COMPREHENSIVE PSYCHONEUROENDOCRINOLOGY 2023; 15:100189. [PMID: 37577297 PMCID: PMC10422098 DOI: 10.1016/j.cpnec.2023.100189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 06/13/2023] [Accepted: 06/15/2023] [Indexed: 08/15/2023] Open
Abstract
The purpose of this narrative review is to use a personal perspective to describe unanticipated and pivotal findings that drew the author into the study oxytocin. Oxytocin was originally described as a "female reproductive hormone." However, supporting reproduction is only one of a myriad of functions now attributed to oxytocin. Oxytocin promotes survival and resilience in both sexes and across the lifespan, especially in the context of stress or trauma and helps to explain the health benefits of relationships. Oxytocin works in the context of individual histories and in conjunction with other molecules, as well as the autonomic nervous system and immune factors. The chemical properties of oxytocin make it biologically active, but difficult to measure. As a deeper understanding of the biology of oxytocin is emerging, we may use knowledge of the properties of oxytocin to uncover adaptive strategies that protect and heal in the face of stress and adversity in both males and females.
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Affiliation(s)
- C. Sue Carter
- Kinsey Institute, Indiana University, Bloomington, IN, USA
- Department of Psychology, University of Virginia, Charlotteville, VA, USA
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8
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Gan HW, Leeson C, Aitkenhead H, Dattani M. Inaccuracies in plasma oxytocin extraction and enzyme immunoassay techniques. COMPREHENSIVE PSYCHONEUROENDOCRINOLOGY 2023; 15:100188. [PMID: 37360277 PMCID: PMC10285453 DOI: 10.1016/j.cpnec.2023.100188] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 06/01/2023] [Accepted: 06/04/2023] [Indexed: 06/28/2023] Open
Abstract
Numerous studies have reported extensive associations between plasma oxytocin (OXT) concentrations and various human physiological and neurobehavioral processes. Measurement of OXT is fraught with difficulty due to its low molecular weight and plasma concentrations, with no consensus as to the optimal conditions for pre-analytical sample extraction, standards for immunoassay validation or the ideal protease inhibitors to prevent OXT degradation. Previous attempts at determining the efficacy of various purification techniques such as solid phase extraction (SPE) or ultrafiltration have only utilized human plasma samples, making it difficult to dissect out whether the effect of interference comes from the extraction process itself or cross-reactivity with other proteins. By testing these on pure OXT solutions, we demonstrate poor recovery efficacy and reliability of reversed phase SPE (maximum 58.1%) and ultrafiltration (<1%) techniques, and the potential for the former to introduce interference into enzyme immunoassay (EIA) measurements. The clonality of antibodies used in EIA kits also potentially contributes to the differences in the readings obtained, and we validate an EIA kit which did not require pre-analytical sample extraction with low cross-reactivity and high reliability (intraclass correlation coefficient 0.980 (95% CI 0.896-0.999). Biochemical techniques used for measuring plasma OXT concentrations must therefore be internally validated prior to translation into clinical studies.
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Affiliation(s)
- Hoong-Wei Gan
- Genetics & Genomic Medicine Research and Training Department, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, United Kingdom
- Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London, WC1N 3JH, United Kingdom
| | - Clare Leeson
- Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London, WC1N 3JH, United Kingdom
| | - Helen Aitkenhead
- Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London, WC1N 3JH, United Kingdom
| | - Mehul Dattani
- Genetics & Genomic Medicine Research and Training Department, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, United Kingdom
- Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London, WC1N 3JH, United Kingdom
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López-Arjona M, Botía M, Martínez-Subiela S, Cerón JJ. Oxytocin measurements in saliva: an analytical perspective. BMC Vet Res 2023; 19:96. [PMID: 37507690 PMCID: PMC10386254 DOI: 10.1186/s12917-023-03661-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 07/14/2023] [Indexed: 07/30/2023] Open
Abstract
Oxytocin has traditionally been known for its physiological effects on muscle contraction associated with birth and lactation, but in the last years is widely used as a biomarker of "positive experiences" in psychology and behavior. Different types of samples have been used for oxytocin measurements with saliva samples having the particular advantage of an easy and non-stressful collection. However, the low concentration of oxytocin in saliva can represent a limitation for its use. For this reason, sensitive assays and even a previous sample treatment in some cases are required for saliva oxytocin quantification. In addition, the lack of standardized and generally agreed-upon approach to peripheral oxytocin measurement leads to large discrepancies between different laboratories, that use different sample treatment protocols and different assays. The main objectives of this review are to describe the current status of the use of saliva for oxytocin measurement, provide details of the different sample processing techniques that can be applied and inform about the analytical techniques and assays available in different animal species, and also in humans for comparative purposes. It is expected that this information can contribute to an increase in the knowledge about the measurements of oxytocin in saliva and to its wider use in the future.
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Affiliation(s)
- Marina López-Arjona
- Department of Animal and Food Science, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, 08193, Spain.
| | - María Botía
- Interdisciplinary Laboratory of Clinical Analysis, Regional Campus of International Excellence 'Campus Mare Nostrum', University of Murcia (Interlab-UMU), University of Murcia, Campus de Espinardo s/n, Murcia, 30100, Spain
| | - Silvia Martínez-Subiela
- Interdisciplinary Laboratory of Clinical Analysis, Regional Campus of International Excellence 'Campus Mare Nostrum', University of Murcia (Interlab-UMU), University of Murcia, Campus de Espinardo s/n, Murcia, 30100, Spain
| | - José Joaquín Cerón
- Interdisciplinary Laboratory of Clinical Analysis, Regional Campus of International Excellence 'Campus Mare Nostrum', University of Murcia (Interlab-UMU), University of Murcia, Campus de Espinardo s/n, Murcia, 30100, Spain
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Hassan S, El Baradey H, Madi M, Shebl M, Leng G, Lozic M, Ludwig M, Menzies J, MacGregor D. Measuring oxytocin release in response to gavage: Computational modelling and assay validation. J Neuroendocrinol 2023; 35:e13303. [PMID: 37316906 PMCID: PMC10909523 DOI: 10.1111/jne.13303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 04/18/2023] [Accepted: 04/28/2023] [Indexed: 06/16/2023]
Abstract
In the present experiments, we tested the conclusion from previous electrophysiological experiments that gavage of sweet food and systemically applied insulin both stimulate oxytocin secretion. To do so, we measured oxytocin secretion from urethane-anaesthetised male rats, and demonstrated a significant increase in secretion in response to gavage of sweetened condensed milk but not isocaloric cream, and a significant increase in response to intravenous injection of insulin. We compared the measurements made in response to sweetened condensed milk with the predictions from a computational model, which we used to predict plasma concentrations of oxytocin from the published electrophysiological responses of oxytocin cells. The prediction from the computational model was very closely aligned to the levels of oxytocin measured in rats in response to gavage.
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Affiliation(s)
- Shereen Hassan
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
- Department of Medical Physiology, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Hala El Baradey
- Department of Medical Physiology, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Mohamed Madi
- Department of Medical Physiology, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Mohamed Shebl
- Department of Medical Physiology, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Gareth Leng
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Maja Lozic
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Mike Ludwig
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
- Centre for Neuroendocrinology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - John Menzies
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Duncan MacGregor
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
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Tabak BA, Leng G, Szeto A, Parker KJ, Verbalis JG, Ziegler TE, Lee MR, Neumann ID, Mendez AJ. Advances in human oxytocin measurement: challenges and proposed solutions. Mol Psychiatry 2023; 28:127-140. [PMID: 35999276 PMCID: PMC9812775 DOI: 10.1038/s41380-022-01719-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 07/18/2022] [Accepted: 07/21/2022] [Indexed: 01/09/2023]
Abstract
Oxytocin, a neuropeptide known for its role in reproduction and socioemotional processes, may hold promise as a therapeutic agent in treating social impairments in patient populations. However, research has yet to uncover precisely how to manipulate this system for clinical benefit. Moreover, inconsistent use of standardized and validated oxytocin measurement methodologies-including the design and study of hormone secretion and biochemical assays-present unresolved challenges. Human studies measuring peripheral (i.e., in plasma, saliva, or urine) or central (i.e., in cerebrospinal fluid) oxytocin concentrations have involved very diverse methods, including the use of different assay techniques, further compounding this problem. In the present review, we describe the scientific value in measuring human endogenous oxytocin concentrations, common issues in biochemical analysis and study design that researchers face when doing so, and our recommendations for improving studies using valid and reliable methodologies.
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Affiliation(s)
- Benjamin A Tabak
- Department of Psychology, Southern Methodist University, Dallas, TX, USA.
| | - Gareth Leng
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Angela Szeto
- Department of Psychology, University of Miami, Coral Gables, FL, USA
| | - Karen J Parker
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Department of Comparative Medicine, Stanford University, Stanford, CA, USA
| | - Joseph G Verbalis
- Division of Endocrinology and Metabolism, Department of Medicine, Georgetown University Medical Center, Washington, DC, USA
| | - Toni E Ziegler
- Assay Services Unit and Institute for Clinical and Translational Research Core Laboratory, National Primate Research Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Mary R Lee
- Veterans Affairs Medical Center, Washington, DC, USA
| | - Inga D Neumann
- Department of Behaviour and Molecular Neurobiology, University of Regensburg, Regensburg, Germany
| | - Armando J Mendez
- Diabetes Research Institute, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL, USA
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Carter CS. Sex, love and oxytocin: Two metaphors and a molecule. Neurosci Biobehav Rev 2022; 143:104948. [PMID: 36347382 PMCID: PMC9759207 DOI: 10.1016/j.neubiorev.2022.104948] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 11/02/2022] [Accepted: 11/03/2022] [Indexed: 11/06/2022]
Abstract
Dozens of studies, most conducted in the last four decades, have implicated oxytocin, as well as vasopressin and their receptors, in processes that mediate selective sociality and the consequences of early experience. Oxytocin is critical for the capacity to experience emotional safety and healthy sexuality. Oxytocin also plays a central role in almost every aspect of physical and mental health, including the coordination of sociality and loving relationships with physiological reactions to challenges across the lifespan. Species, including prairie voles, that share with humans the capacity for selective social bonds have been a particularly rich source of insights into the behavioral importance of peptides. The purpose of this historical review is to describe the discovery of a central role for oxytocin in behavioral interactions associated with love, and in the capacity to use sociality to anticipate and cope with challenges across the lifespan - a process that here is called "sociostasis."
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Affiliation(s)
- C Sue Carter
- Department of Psychology, University of Virginia, Charlottesville, VA 22904, USA; Kinsey Institute, Indiana University, Bloomington, IN 47405, USA.
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13
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Leng G, Leng RI, Ludwig M. Oxytocin—a social peptide? Deconstructing the evidence. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210055. [PMID: 35858110 PMCID: PMC9272144 DOI: 10.1098/rstb.2021.0055] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In this paper, we analyse the claim that oxytocin is a ‘social neuropeptide’. This claim originated from evidence that oxytocin was instrumental in the initiation of maternal behaviour and it was extended to become the claim that oxytocin has a key role in promoting social interactions between individuals. We begin by considering the structure of the scientific literature on this topic, identifying closely interconnected clusters of papers on particular themes. We then analyse this claim by considering evidence of four types as generated by these clusters: (i) mechanistic studies in animal models, designed to understand the pathways involved in the behavioural effects of centrally administered oxytocin; (ii) evidence from observational studies indicating an association between oxytocin signalling pathways and social behaviour; (iii) evidence from intervention studies, mainly involving intranasal oxytocin administration; and (iv) evidence from translational studies of patients with disorders of social behaviour. We then critically analyse the most highly cited papers in each segment of the evidence; we conclude that, if these represent the best evidence, then the evidence for the claim is weak. This article is part of the theme issue ‘Interplays between oxytocin and other neuromodulators in shaping complex social behaviours’.
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Affiliation(s)
- Gareth Leng
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, 15 George Square, Edinburgh EH8 9XD, UK
| | - Rhodri I. Leng
- Department of Science, Technology and Innovation Studies, University of Edinburgh, Edinburgh, UK
| | - Mike Ludwig
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, 15 George Square, Edinburgh EH8 9XD, UK
- Faculty of Health Sciences, Centre for Neuroendocrinology, University of Pretoria, Pretoria, South Africa
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14
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Carter CS, Kingsbury MA. Oxytocin and oxygen: the evolution of a solution to the ‘stress of life’. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210054. [PMID: 35856299 PMCID: PMC9272143 DOI: 10.1098/rstb.2021.0054] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Oxytocin (OT) and the OT receptor occupy essential roles in our current understanding of mammalian evolution, survival, sociality and reproduction. This narrative review examines the hypothesis that many functions attributed to OT can be traced back to conditions on early Earth, including challenges associated with managing life in the presence of oxygen and other basic elements, including sulfur. OT regulates oxidative stress and inflammation especially through effects on the mitochondria. A related nonapeptide, vasopressin, as well as molecules in the hypothalamic–pituitary–adrenal axis, including the corticotropin-releasing hormone family of molecules, have a broad set of functions that interact with OT. Interactions among these molecules have roles in the causes and consequence of social behaviour and the management of threat, fear and stress. Here, we discuss emerging evidence suggesting that unique properties of the OT system allowed vertebrates, and especially mammals, to manage over-reactivity to the ‘side effects’ of oxygen, including inflammation, oxidation and free radicals, while also supporting high levels of sociality and a perception of safety. This article is part of the theme issue ‘Interplays between oxytocin and other neuromodulators in shaping complex social behaviours’.
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Affiliation(s)
- C. Sue Carter
- Kinsey Institute, Indiana University, Bloomington, IN 47405, USA
- Department of Psychology, University of Virginia, Charlottesville, VA 22904, USA
| | - Marcy A. Kingsbury
- Lurie Center for Autism, Mass General Hospital for Children, Harvard University Medical School, Charlestown, Boston, MA 02129, USA
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15
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Bowling DL, Gahr J, Ancochea PG, Hoeschele M, Canoine V, Fusani L, Fitch WT. Endogenous oxytocin, cortisol, and testosterone in response to group singing. Horm Behav 2022; 139:105105. [PMID: 34999566 PMCID: PMC8915780 DOI: 10.1016/j.yhbeh.2021.105105] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 12/01/2021] [Accepted: 12/22/2021] [Indexed: 12/30/2022]
Abstract
Humans have sung together for thousands of years. Today, regular participation in group singing is associated with benefits across psychological and biological dimensions of human health. Here we examine the hypothesis that a portion of these benefits stem from changes in endocrine activity associated with affiliation and social bonding. Working with a young adult choir (n = 71), we measured changes salivary concentrations of oxytocin, cortisol, and testosterone from before and after four experimental conditions crossing two factors: vocal production mode (singing vs. speaking) and social context (together vs. alone). Salivary oxytocin and cortisol decreased from before to after the experimental manipulations. For oxytocin the magnitude of this decrease was significantly smaller after singing compared to speaking, resulting in concentrations that were significantly elevated after singing together compared to speaking together, after controlling for baseline differences. In contrast, the magnitude of the salivary cortisol decreases was the same across experimental manipulations, and although large, could not be separated from diurnal cycling. No significant effects were found in a low-powered exploratory evaluation of testosterone (tested only in males). At a psychological level, we found that singing stimulates greater positive shifts in self-perceived affect compared to speaking-particularly when performed together-and that singing together enhances feelings of social connection more than speaking together. Finally, measurements of heart rate made for a subset of participants provide preliminary evidence regarding physical exertion levels across conditions. These results are discussed in the context of a growing multidisciplinary literature on the endocrinological correlates of musical behavior. We conclude that singing together can have biological and psychological effects associated with affiliation and social bonding, and that these effects extend beyond comparable but non-musical group activities. However, we also note that these effects appear heavily influenced by broader contextual factors that shape social dynamics, such as stress levels, the intimacy of interactions, and the status of existing relationships.
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Affiliation(s)
- D L Bowling
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, United States of America; Department of Behavioral & Cognitive Biology, University of Vienna, Austria.
| | - J Gahr
- Department of Behavioral & Cognitive Biology, University of Vienna, Austria
| | - P Graf Ancochea
- Department of Behavioral & Cognitive Biology, University of Vienna, Austria
| | - M Hoeschele
- Department of Behavioral & Cognitive Biology, University of Vienna, Austria; Acoustics Research Institute, Austrian Academy of Sciences, Austria
| | - V Canoine
- Department of Behavioral & Cognitive Biology, University of Vienna, Austria
| | - L Fusani
- Department of Behavioral & Cognitive Biology, University of Vienna, Austria; Konrad Lorenz Institute of Ethology, University of Veterinary Medicine, Vienna, Austria
| | - W T Fitch
- Department of Behavioral & Cognitive Biology, University of Vienna, Austria; CogSci Hub University of Vienna, Austria
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16
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Carter CS. Oxytocin and love: Myths, metaphors and mysteries. COMPREHENSIVE PSYCHONEUROENDOCRINOLOGY 2022; 9:100107. [PMID: 35755926 PMCID: PMC9216351 DOI: 10.1016/j.cpnec.2021.100107] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 12/15/2021] [Indexed: 12/15/2022] Open
Abstract
Oxytocin is a peptide molecule with a multitude of physiological and behavioral functions. Based on its association with reproduction - including social bonding, sexual behavior, birth and maternal behavior - oxytocin also has been called “the love hormone.” This essay specifically examines association and parallels between oxytocin and love. However, many myths and gaps in knowledge remain concerning both. A few of these are described here and we hypothesize that the potential benefits of both love and oxytocin may be better understood in light of interactions with more ancient systems, including specifically vasopressin and the immune system. Oxytocin is anti-inflammatory and is associated with recently evolved, social solutions to a variety of challenges necessary for mammalian survival and reproduction. The shared functions of oxytocin and love have profound implications for health and longevity, including the prevention and treatment of excess inflammation and related disorders, especially those occurring in early life and during periods of chronic threat or disease. Oxytocin is a peptide molecule with functions that support a sense of safety, sociality, as well as survival and reproduction. Oxytocin is associated with social and neuroimmune solutions to chronic stress. The related, but more primitive, peptide vasopressin supports more individualistic survival strategies. Controversies and myths surround the properties of oxytocin and love.
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Cherepanov SM, Gerasimenko M, Yuhi T, Shabalova A, Zhu H, Yokoyama S, Salmina AB, Munesue SI, Harashima A, Yamamoto Y, Higashida H. An improved sample extraction method reveals that plasma receptor for advanced glycation end-products (RAGE) modulates circulating free oxytocin in mice. Peptides 2021; 146:170649. [PMID: 34543678 DOI: 10.1016/j.peptides.2021.170649] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 09/15/2021] [Accepted: 09/15/2021] [Indexed: 12/21/2022]
Abstract
The receptor for advanced glycation end-products (RAGE) binds oxytocin (OT) and transports it from the blood to the brain. As RAGE's OT-binding capacity was lost in RAGE knockout (KO) mice, we predicted that circulating concentrations of unbound (free) OT should be elevated compared to wild-type (WT) mice. However, this hypothesis has not yet been investigated. Unfortunately, the evaluation of the dynamics of circulating free and bound plasma OT is unclear in immunoassays, in part because of interference from plasma proteins. A radioimmunoassay (RIA) is considered the gold standard method for overcoming this issue, but is more challenging to implement; thus, commercially available enzyme-linked immunosorbent assays (ELISAs) are more commonly used. Here, we developed a pre-treatment method to remove the interference-causing components from plasma before performing ELISA. The acetonitrile protein precipitation (PPT) approach was reliable, with fewer steps needed to measure free OT concentrations than by solid-phase extraction of plasma samples. PPT-extracted plasma samples yielded higher concentrations of OT in RAGE KO mice than in WT mice using ELISA. After peripheral OT injection, free OT plasma levels spiked immediately then rapidly declined in WT mice, but remained high in KO mice. These results suggest that plasma samples with PPT pre-treatment appear to be superior and that circulating soluble RAGE can most likely serve as a buffer for plasma OT, which indicates a novel physiological function of RAGE.
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Affiliation(s)
- Stanislav M Cherepanov
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa, 920-8640, Japan
| | - Maria Gerasimenko
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa, 920-8640, Japan
| | - Teruko Yuhi
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa, 920-8640, Japan
| | - Anna Shabalova
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa, 920-8640, Japan
| | - Hong Zhu
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa, 920-8640, Japan
| | - Shigeru Yokoyama
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa, 920-8640, Japan
| | - Alla B Salmina
- Laboratory for Social Brain Studies, Research Institute of Molecular Medicine and Pathobiochemistry, and Department of Biochemistry, Krasnoyarsk State Medical University named after Prof. V. F. Voino-Yasentsky, Krasnoyarsk, 660022, Russia
| | - Shei-Ichi Munesue
- Department of Biochemistry and Molecular Vascular Biology, Kanazawa University Graduate School of Medical Sciences, Kanazawa, 920-8640, Japan
| | - Ai Harashima
- Department of Biochemistry and Molecular Vascular Biology, Kanazawa University Graduate School of Medical Sciences, Kanazawa, 920-8640, Japan
| | - Yasuhiko Yamamoto
- Department of Biochemistry and Molecular Vascular Biology, Kanazawa University Graduate School of Medical Sciences, Kanazawa, 920-8640, Japan
| | - Haruhiro Higashida
- Department of Basic Research on Social Recognition and Memory, Research Center for Child Mental Development, Kanazawa University, Kanazawa, 920-8640, Japan.
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