Salivary Oxytocin Levels Research Articles

Frontiers in oxytocin science: from basic to practice

Oxytocin is a paramount social hormone in mammals and accumulating evidence also strengthens a leading role of this nonapeptide in human social behavior. From voles to men, oxytocin modulates an intriguing number of social behaviors that resonates across species. Behaviors modulated by oxytocin include the quality of pair bonding, parenting, social stress, in-group and out-group relationships, and social communications. Recent molecular genetic studies of the human oxytocin receptor (OXTR) gene have strengthened the evidence regarding the role of this nonapeptide in a range of normal and pathological human behaviors. Moreover, dysfunctions in the oxytocin neural pathways are likely contributing to deficits in social skills and communication in several psychiatric disorders. Indeed, a growing number of clinical studies are now testing the therapeutic effect of intranasal oxytocin administration in mental disorders- from autism to schizophrenia. Our social behavior is extraordinarily complex and is mediated by multiple and overlapping systems. Thus, it remains a challenging task to understand the neurobiology and neuroendocrinology underlying this complexity. One of the important determinants of human social behavior is the oxytocin system, which has provided a uniquely promising avenue of research toward revealing the tapestry of these complex social phenotypes. This Research Topic provide a broad view of the current state of oxytocin science in humans and illustrate how pharmacological, genetic, and neuroimaging strategies can be successfully combined toward unraveling the mystery of how human social behavior is regulated. Part A provides several review articles outlining salient facets of current oxytocin research. Lopatina et al. (2013) focus on translational approaches and show how rodent models elucidate the roles of the OXTR and CD38 genes in social behaviors. This review generates new perspectives in clinical therapies for diseases characterized by deficits in social cognition. Kumsta et al. (2013) provide an overview of the functional importance of OXTR promoter region methylation and summarizes a group of epigenetic studies that reveal the role of OXTR methylation signatures in shaping behavioral phenotypes. Quintana et al. (2013) highlight a key role for autonomic cardiac control in social behavior and psychiatric disorders and suggest the intriguing idea that autonomic cardiac control may moderate the relationship between oxytocin and social behavior. MacDonald (2013) discusses three factors that can influence individual responses to intranasal administration of oxytocin; sex and hormonal status, genetic variation, and attachment history. Finally, MacDonald and Feifel (2013) discuss the promise of oxytocin-based therapeutics and identify 10 key questions that future oxytocin research should address to facilitate oxytocin use in clinical medicine and truly deliver this molecule's therapeutic potential. Part B provides several research articles from basic methodology to the powerful strategy combining molecular genetics and neuroimaging, so-called imaging genomics. van IJzendoorn et al. (2012) address the important question of how long salivary oxytocin levels remain elevated following intranasal administration and further examine the effect of different doses of oxytocin administration. Kret and De Dreu (2013) explore the effect of intranasal oxytocin in the context of group formation and further consider the effect of fetal testosterone and empathic concern on this process. Fischer-Shofty et al. (2013) test the effects of intranasal oxytocin administration on fear recognition in schizophrenic patients compared to healthy controls. Finally, Sauer et al. (2013) describe an imaging genomics approach using intranasal oxytocin administration during responses to social stimuli. Specifically, they investigate interactions between oxytocin and dopamine-related genes in contributing to individual differences in the activation of different brain regions. Understanding social behavior in our species is not only clinically extremely relevant for disorders characterized by dysfunctional social relationships, but also research on human social hormones has important implications beyond the clinic. Revealing the biological roots of human social behavior impacts the Social Sciences, including economics, sociology and psychology and moreover, is of great interest to the public at large.

Elevated Salivary Levels of Oxytocin Persist More than 7 h after Intranasal Administration

We addressed the question how long salivary oxytocin levels remain elevated after intranasal administration, and whether it makes a difference when 16 or 24 IU of oxytocin administration is used. Oxytocin levels were measured in saliva samples collected from 46 female participants right before intranasal administration (at 9:30 a.m.) of 16 IU (n = 18) or 24 IU (n = 10) of oxytocin, or a placebo (n = 18), and each hour after administration, for 7 h in total. Oxytocin levels did not differ among conditions before use of the nasal spray. Salivary oxytocin levels in the placebo group showed high stability across the day. After oxytocin administration oxytocin levels markedly increased, they peaked around 1 h after administration, and were still significantly elevated 7 h after administration. The amount of oxytocin (16 or 24 IU) did not make a difference for oxytocin levels. The increase of oxytocin levels for at least 7 h shows how effective intranasal administration of oxytocin is. Our findings may raise ethical questions about potentially persisting behavioral effects after participants have left the lab setting. More research into the long-term neurological and behavioral effects of sniffs of oxytocin is urgently needed.

The influence of depressive symptomatology and perceived stress on plasma and salivary oxytocin before, during and after a support enhancement intervention

Oxytocin (OT) activity increases in response to stress as well as to warm social contact. Subclinical depression is associated with higher stress but less reward from social contacts. The present investigation was intended to examine whether husbands and wives with high depressive symptomatology scores have increased plasma and salivary OT that may be mediated partly by higher perceived stress, and also to assess whether an intervention to convey partner support through "warm touch" may reduce effects of depressive symptoms on OT. In this study, 34 healthy married couples (n=68) ages 20-39 provided self reports of depressive symptoms (CESD) and stress (Perceived Stress Scale) before being randomly assigned to a 4-week intervention study enhancing partner support through "warm touch", or to a "behavior monitoring" control group. Plasma oxytocin levels were obtained pre- and post-intervention, while salivary oxytocin was taken at home during week 1 and week 4. Results revealed that subjects with higher depressive symptoms scores had higher plasma OT levels at pre-intervention, and higher salivary OT levels at home during week 1 (p<.05). Plasma OT results were moderated by gender such that plasma OT levels were highest among females high in depressive symptomology. Higher perceived stress was also linked to both higher depressive symptomatology (r=+65, p<.0001) and plasma OT (p< .05) and a significant mediator. During the intervention, salivary OT remained elevated among subjects high in depressive symptomatology in the control group but not the intervention group. At post-intervention, plasma OT levels in subjects with vs. without depressive symptomatology no longer differed. Results indicate that subclinical depression is associated with elevated plasma and salivary OT levels, which may be mediated in part by increased stress. OT differences linked to subclinical depression were minimized by the warm touch intervention.

Detection of salivary oxytocin levels in lactating women

Oxytocin is a neuropeptide with widespread influence on many physiological and social functions including: labor and birth, lactation, sexual behavior, nurturing maternal behaviors, and stress reduction. However, our understanding of oxytocin's roles has been hampered by lack of noninvasive methods for assessing oxytocin levels. The goal of the present study was to assess whether oxytocin could be detected in saliva and whether changes occurred in the pattern of oxytocin release among lactating women from before, at initiation and after breast feeding. Using a prospective repeated measures design, 11 research participants each provided 18 saliva samples during three feeding cycles (before, at initiation and after breast feeding) for two 24-hr data collection periods (Days 1 and 2). Within each day, saliva was collected at late evening, early morning, and late morning. Salivary samples were concentrated fourfold by dehydration prior to analysis and oxytocin was measured in saliva using an enzyme immunoassay (EIA). Salivary oxytocin values, when reconverted to their original levels, ranged from 6.44 to 61.05 pg/ml. Oxytocin values in saliva varied significantly as a function of the breast feeding cycle, but did not show reliable differences as a function of the time of feeding. Oxytocin was highest before feeding, followed by a decrease at initiation of feeding, and an increase at 30 min after feeding. The findings suggest that oxytocin release into saliva increases in anticipation of feedings. This study also supports the potential usefulness of salivary measures of oxytocin as a noninvasive index of changes in this peptide.