Local oxytocin tempers anxiety by activating GABAA receptors in the hypothalamic paraventricular nucleus

Chronic stress produces enduring sex- and region-specific alterations in novel stress-induced c-Fos expression

Prolonged or repeated exposure to stress increases risk for a variety of psychological disorders, many of which are marked by dysfunction of corticolimbic brain regions. Notably, women are more likely than men to be diagnosed with these disorders, especially when onset of symptoms follows stressful life events. Using rodent models, investigators have recently begun to elucidate sex-specific changes in the brain and behavior that occur immediately following chronic stress. However, little is known regarding the lasting sequelae of chronic stress, as well as how potential changes may impact responsivity to future stressors. We recently demonstrated that male and female rats show different patterns of dendritic reorganization in medial prefrontal cortex in the days following chronic stress. Here, we examined the immediate and lasting effects of chronic restraint stress (CRS; 3 h/day, 10 days) on neuronal activation, across several corticolimbic brain regions, induced by novel acute stress exposure. Chronically stressed male and female rats were exposed to acute elevated platform stress (EPS) either 1 (CRS-EPS) or 7 (CRS-Rest-EPS) days after CRS. Compared to rats exposed to EPS only, significant reductions in acute stress-induced c-Fos expression were observed in the medial prefrontal cortex, hippocampus, and paraventricular nucleus of the hypothalamus (PVN) in CRS-EPS male rats, some of which persisted to 7 days post-stress. In contrast, we found little modulation of novel stress-induced c-Fos expression in CRS-EPS female rats. However, CRS-Rest-EPS female rats exhibited a significant enhancement of acute stress-induced neuronal activity in the PVN. Together, these data show that prior chronic stress produces sex- and region-specific alterations in novel stress-induced neuronal activation, which are dependent on the presence or absence of a rest period following chronic stress. These findings suggest that the post-stress rest period may give rise to sex-specific neuroadaptations to stress, which may underlie sex differences in stress susceptibility versus resilience.

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In males, chronic stress blunts corticolimbic activation to a novel stressor.

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A post-stress rest period restores acute stress responsivity in male rats.

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In females, chronic stress blunts activation to novel stress in OFC only.

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After a post-stress rest period, novel stress enhances c-Fos in PVN and BLA in females.

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The post-stress rest period may give rise to sex-specific neuroadaptations to stress.

Yoga: Balancing the excitation-inhibition equilibrium in psychiatric disorders

Social behavioral disturbances are central to most psychiatric disorders. A disequilibrium within the cortical excitatory and inhibitory neurotransmitter systems underlies these deficits. Gamma-aminobutyric acid (GABA) and glutamate are the most abundant excitatory and inhibitory neurotransmitters in the brain that contribute to this equilibrium. Several contemporary therapies used in treating psychiatric disorders, regulate this GABA-glutamate balance. Yoga has been studied as an adjuvant treatment across a broad range of psychiatric disorders and is shown to have short-term therapeutic gains. Emerging evidence from recent clinical in vivo experiments suggests that yoga improves GABA-mediated cortical-inhibitory tone and enhances peripheral oxytocin levels. This is likely to have a more controlled downstream response of the hypothalamo-pituitary-adrenal system by means of reduced cortisol release and hence a blunted sympathetic response to stress. Animal and early fetal developmental studies suggest an inter-dependent role of oxytocin and GABA in regulating social behaviors. In keeping with these observations, we propose an integrated neurobiological model to study the mechanisms of therapeutic benefits with yoga. Apart from providing a neuroscientific basis for applying a traditional system of practice in the clinical setting, this model can be used as a framework for studying yoga mechanisms in future clinical trials.

Acute and long-lasting effects of oxytocin in cortico-limbic circuits: consequences for fear recall and extinction

The extinction of conditioned fear responses entrains the formation of safe new memories to decrease those behavioral responses. The knowledge in neuronal mechanisms of extinction is fundamental in the treatment of anxiety and fear disorders. Interestingly, the use of pharmacological compounds that reduce anxiety and fear has been shown as a potent co-adjuvant in extinction therapy. However, the efficiency and mechanisms by which pharmacological compounds promote extinction of fear memories remains still largely unknown and would benefit from a validation based on functional neuronal circuits, and the neurotransmitters that modulate them. From this perspective, oxytocin receptor signaling, which has been shown in cortical and limbic areas to modulate numerous functions (Eliava et al. Neuron 89(6):1291-1304, 2016), among them fear and anxiety circuits, and to enhance the salience of social stimuli (Stoop Neuron 76(1):142-59, 2012), may offer an interesting perspective. Experiments in animals and humans suggest that oxytocin could be a promising pharmacological agent at adjusting memory consolidation to boost fear extinction. Additionally, it is possible that long-term changes in endogenous oxytocin signaling can also play a role in reducing expression of fear at different brain targets. In this review, we summarize the effects reported for oxytocin in cortico-limbic circuits and on fear behavior that are of relevance for the modulation and potential extinction of fear memories.

Genetic Predisposition for Immune System, Hormone, and Metabolic Dysfunction in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Pilot Study

Introduction: Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome (ME/CFS) is a multifactorial illness of unknown etiology with considerable social and economic impact. To investigate a putative genetic predisposition to ME/CFS we conducted genome-wide single-nucleotide polymorphism (SNP) analysis to identify possible variants. Methods: 383 ME/CFS participants underwent DNA testing using the commercial company 23andMe. The deidentified genetic data was then filtered to include only non-synonymous and nonsense SNPs from exons and microRNAs, and SNPs close to splice sites. The frequencies of each SNP were calculated within our cohort and compared to frequencies from the Kaviar reference database. Functional annotation of pathway sets containing SNP genes with high frequency in ME/CFS was performed using over-representation analysis via ConsensusPathDB. Furthermore, these SNPs were also scored using the Combined Annotation Dependent Depletion (CADD) algorithm to gauge their deleteriousness. Results: 5693 SNPs were found to have at least 10% frequency in at least one cohort (ME/CFS or reference) and at least two-fold absolute difference for ME/CFS. Functional analysis identified the majority of SNPs as related to immune system, hormone, metabolic, and extracellular matrix organization. CADD scoring identified 517 SNPs in these pathways that are among the 10% most deleteriousness substitutions to the human genome.

Neural responses to familiar conspecifics are modulated by a nonapeptide receptor in a winter flocking sparrow

The social behavior network, a collection of reciprocally connected areas within the basal forebrain and midbrain, plays a conserved role in the regulation of vertebrate social behavior. Specific behaviors are associated with patterns of activity across the network, and these activity profiles vary with species and context. We investigated how the social behavior network responds to familiar social stimuli in a seasonally flocking songbird. Further, we explored how socially-induced neural responses are modulated by endogenous nonapeptide receptor blockade. Winter flocking dark-eyed juncos were exposed to either familiar conspecifics or a familiar empty aviary following a peripheral injection of either saline or [desGly-NH₂,d(CH₂)₅, Tyr(Me)²,Thr⁴]-ornithine vasotocin, an VT3 receptor antagonist. Socially-exposed animals exhibited greater Fos induction across the social behavior network. Sex and drug effects were site-specific, with females tending to exhibit greater Fos responses to social stimuli and a greater sensitivity to VT3 antagonism. We suggest that in flocking animals, VT3 activation during social interaction may shift the pattern of neural activity towards the dorsocaudal lateral septum and rostral arcopallium and away from the extended amygdala, anterior and ventromedial hypothalamus, and the caudal ventral/ventrolateral lateral septum.

Mitochondria, Oxytocin, and Vasopressin: Unfolding the Inflammatory Protein Response

Neuroendocrine and immune signaling pathways are activated following insults such as stress, injury, and infection, in a systemic response aimed at restoring homeostasis. Mitochondrial metabolism and function have been implicated in the control of immune responses. Commonly studied along with mitochondrial function, reactive oxygen species (ROS) are closely linked to cellular inflammatory responses. It is also accepted that cells experiencing mitochondrial or endoplasmic reticulum (ER) stress induce response pathways in order to cope with protein-folding dysregulation, in homeostatic responses referred to as the unfolded protein responses (UPRs). Recent reports indicate that the UPRs may play an important role in immune responses. Notably, the homeostasis-regulating hormones oxytocin (OXT) and vasopressin (AVP) are also associated with the regulation of inflammatory responses and immune function. Intriguingly, OXT and AVP have been linked with ER unfolded protein responses (UPR^ER), and can impact ROS production and mitochondrial function. Here, we will review the evidence for interactions between these various factors and how these neuropeptides might influence mitochondrial processes.

Oxytocin facilitates adaptive fear and attenuates anxiety responses in animal models and human studies-potential interaction with the corticotropin-releasing factor (CRF) system in the bed nucleus of the stria terminalis (BNST)

Despite its relatively well-understood role as a reproductive and pro-social peptide, oxytocin (OT) tells a more convoluted story in terms of its modulation of fear and anxiety. This nuanced story has been obscured by a great deal of research into the therapeutic applications of exogenous OT, driving more than 400 ongoing clinical trials. Drawing from animal models and human studies, we review the complex evidence concerning OT's role in fear learning and anxiety, clarifying the existing confusion about modulation of fear versus anxiety. We discuss animal models and human studies demonstrating the prevailing role of OT in strengthening fear memory to a discrete signal or cue, which allows accurate and rapid threat detection that facilitates survival. We also review ostensibly contrasting behavioral studies that nonetheless provide compelling evidence of OT attenuating sustained contextual fear and anxiety-like behavior, arguing that these OT effects on the modulation of fear vs. anxiety are not mutually exclusive. To disambiguate how endogenous OT modulates fear and anxiety, an understudied area compared to exogenous OT, we survey behavioral studies utilizing OT receptor (OTR) antagonists. Based on emerging evidence about the role of OTR in rat dorsolateral bed nucleus of stria terminalis (BNST) and elsewhere, we postulate that OT plays a critical role in facilitating accurate discrimination between stimuli representing threat and safety. Supported by human studies, we demonstrate that OT uniquely facilitates adaptive fear but reduces maladaptive anxiety. Last, we explore the limited literature on endogenous OT and its interaction with corticotropin-releasing factor (CRF) with a special emphasis on the dorsolateral BNST, which may hold the key to the neurobiology of phasic fear and sustained anxiety.

The Oxytocin Receptor: From Intracellular Signaling to Behavior

The many facets of the oxytocin (OXT) system of the brain and periphery elicited nearly 25,000 publications since 1930 (see FIGURE 1 , as listed in PubMed), which revealed central roles for OXT and its receptor (OXTR) in reproduction, and social and emotional behaviors in animal and human studies focusing on mental and physical health and disease. In this review, we discuss the mechanisms of OXT expression and release, expression and binding of the OXTR in brain and periphery, OXTR-coupled signaling cascades, and their involvement in behavioral outcomes to assemble a comprehensive picture of the central and peripheral OXT system. Traditionally known for its role in milk let-down and uterine contraction during labor, OXT also has implications in physiological, and also behavioral, aspects of reproduction, such as sexual and maternal behaviors and pair bonding, but also anxiety, trust, sociability, food intake, or even drug abuse. The many facets of OXT are, on a molecular basis, brought about by a single receptor. The OXTR, a 7-transmembrane G protein-coupled receptor capable of binding to either Gαior Gαqproteins, activates a set of signaling cascades, such as the MAPK, PKC, PLC, or CaMK pathways, which converge on transcription factors like CREB or MEF-2. The cellular response to OXT includes regulation of neurite outgrowth, cellular viability, and increased survival. OXTergic projections in the brain represent anxiety and stress-regulating circuits connecting the paraventricular nucleus of the hypothalamus, amygdala, bed nucleus of the stria terminalis, or the medial prefrontal cortex. Which OXT-induced patterns finally alter the behavior of an animal or a human being is still poorly understood, and studying those OXTR-coupled signaling cascades is one initial step toward a better understanding of the molecular background of those behavioral effects.

The interplay between oxytocin and the CRF system: regulation of the stress response

Oxytocin (OT) has drawn the attention of researchers since 1930. Since then, many aspects of oxytocin have been uncovered, such as reproductive functions, dampening anxiety, enhancing socioemotional behavior, or regulating genomic effects on a cellular level. Here, we want to focus on the interaction between the OT system and the stress/corticotropin-releasing factor (CRF)-system of the brain. Depending on the nature of the stressor, OT is released simultaneously or directly after the stress from the neurohypophysis into the periphery and/or via somato-dendritic release in stress-sensitive brain areas. This stress-induced OT release might serve to modulate or dampen the stress response; however, the functional relevance is not yet fully understood. In this review, we will describe the effects of OT and discuss the interplay between OT and CRF on a cellular, physiological, and behavioral level.

The hemoglobin derived peptide LVV-hemorphin-7 evokes behavioral effects mediated by oxytocin receptors

LVV-hemorphin-7 (LVV-h7) is bioactive peptide resulting from degradation of hemoglobin β-globin chain. LVV-h7 is a specific agonist of angiotensin IV receptor. This receptor belongs to the class of insulin-regulated aminopeptidases (IRAP), which displays oxytocinase activity. Herein, our aims were to assess whether: i) LVV-h7 modifies centrally organized behavior and cardiovascular responses to stress and ii) mechanisms underlying LVV-h7 effects involve activation of oxytocin (OT) receptors, probably as result of reduction of IRAP proteolytic activity upon OT. Adult male Wistar rats (270-370g) received (i.p.) injections of LVV-h7 (153nmol/kg), or vehicle (0.1ml). Different protocols were used: i) open field (OP) test for locomotor/exploratory activities; ii) Elevated Plus Maze (EPM) for anxiety-like behavior; iii) forced swimming test (FST) test for depression-like behavior and iv) air jet for cardiovascular reactivity to acute stress exposure. Diazepam (2mg/kg) and imipramine (15mg/kg) were used as positive control for EPM and FST, respectively. The antagonist of OT receptors (OTr), atosiban (1 and 0,1mg/kg), was used to determine the involvement of oxytocinergic paths. We found that LVV-h7: i) increased the number of entries and the time spent in open arms of the maze, an indicative of anxiolysis; ii) provoked antidepressant effect in the FS test; and iii) increased the exploration and locomotion; iv) did not change the cardiovascular reactivity and neuroendocrine responses to acute stress. Also, increases in locomotion and the antidepressant effects evoked by LVV-h7 were reverted by OTr antagonist. We conclude that LVV-h7 modulates behavior, displays antidepressant and anxiolytic effects that are mediated in part by oxytocin receptors.

Plasma oxytocin levels in major depressive and bipolar II disorders

Oxytocin may play a role in mood regulation. Research has shown the plasma oxytocin level of patients with bipolar I disorder (BD I) during a manic episode was significantly higher than that of BD I patients of other statuses, and also that of healthy subjects. However, whether or not a difference in the level of oxytocin exists between patients with major depressive disorder (MDD) and those with BD II is unclear. This study aimed to investigate the plasma oxytocin levels in MDD and BD II patients in a depressive episode. 119 healthy controls, 135 BD II patients, and 97 MDD patients were enrolled. All of the BD II and MDD patients were drug-naïve, with baseline depressive status 17-item Hamilton Depression Rating Scale scores >15. The plasma oxytocin level of the BD II patients was significantly higher than that of the MDD patients and controls at baseline. After treatment, the plasma oxytocin level of the BD II patients increased significantly; however, in the MDD group, the oxytocin level decreased slightly after treatment. Our findings suggested more significant plasma oxytocin dysregulation in the patients in the BD II group than in the MDD patients and controls, both before and after treatment.

Oxytocin and Anxiety Disorders: Translational and Therapeutic Aspects

PURPOSE OF REVIEW

This review aims to evaluate the most recent literature examining the oxytocin (OXT) system's role in human anxiety by surveying various fields of preclinical and clinical research supporting this role, and queries whether the OXT system might be a target for novel anxiolytics.

RECENT FINDINGS

Evidence from the diverse body of literature presented here, from translational research, genetic and neuroimaging studies, to clinical trials of intranasal (IN) OXT reveals a positive association. In addition, some moderators (e.g., sex, specificities to cues) of OXT's anxiolytic effects can have an important influence on its outcomes, awaiting further research. Evidence for the role of OXT in regulating anxiety is undeniable. We expect that the diverse particularities of the OXT system will help broaden our understanding of anxiety and stress-related disorders. We conclude that OXT promises an enticing treatment option for human anxiety disorders especially those associated with socio-emotional dysfunctions.

Oxytocin in the medial prefrontal cortex attenuates anxiety: Anatomical and receptor specificity and mechanism of action

Numerous studies in animals and humans have established that oxytocin (OT) reduces anxiety. In rats, the prelimbic (PL) subregion of the medial prefrontal cortex (mPFC) is among the brain areas implicated in the anxiolytic actions of OT. However, questions remain about the anatomical and receptor specificity of OT and its mechanism of action. Here we assessed whether the regulation of anxiety by mPFC OT is restricted to the PL subregion and evaluated whether oxytocin receptor (OTR) activation is required for OT to have an anxiolytic effect. We also examined whether OT interacts with GABA in the mPFC to reduce anxiety and investigated the extent to which OT in the mPFC affects activation of mPFC GABA neurons as well as neuronal activation in the amygdala, a primary target of the mPFC which is part of the neural network regulating anxiety. We found that OT reduced anxiety-like behavior when delivered to the PL, but not infralimbic or anterior cingulate subregions of the mPFC. The anxiolytic effect of OT in the PL mPFC was blocked by pretreatment with an OTR, but not a vasopressin receptor, antagonist as well as with a GABA_A receptor antagonist. Lastly, administration of OT to the PL mPFC was accompanied by increased activation of GABA neurons in the PL mPFC and altered neuronal activation of the amygdala following anxiety testing. These results demonstrate that OT in the PL mPFC attenuates anxiety-related behavior and may do so by engaging GABAergic neurons which ultimately modulate downstream brain regions implicated in anxiety.

[Oxytocin and the mechanisms of alcohol dependence]

One of the crucial purposes of treating alcohol-dependent patients is to enhance their ability to stay abstinent after detoxification therapy. Anxiety and stress vulnerability are the main factors provoking alcohol craving and relapse. In the first months of abstinence, alcohol-dependent patients frequently show sleep disturbances, irritability and depression, indicating chronic activation of stress pathways. In addition, the loss of confidence in interpersonal interactions results in social withdrawal and reduced willingness to participate in therapeutic programs.Current research shows that the peptide hormone oxytocin exerts substantial anxiolytic effects and facilitates prosocial behavior. Oxytocin can be safely applied as intranasal preparation. Oxytocin acts by inhibiting the effects of the corticotropin-releasing factor on GABAergic interneurons in the amygdala and paraventricular nucleus of hypothalamus.Recent research strongly suggests that application of oxytocin may beneficially influence the mechanisms of relapse and craving by reduction of anxiety, stress vulnerability and social withdrawal in abstinent alcohol-dependent patients.This article reviews neurobiological mechanisms of oxytocin effects on stress-related pathways and discusses the potential use of oxytocin in the treatment of alcohol addiction.

Microbial lysate upregulates host oxytocin

Neuropeptide hormone oxytocin has roles in social bonding, energy metabolism, and wound healing contributing to good physical, mental and social health. It was previously shown that feeding of a human commensal microbe Lactobacillus reuteri (L. reuteri) is sufficient to up-regulate endogenous oxytocin levels and improve wound healing capacity in mice. Here we show that oral L. reuteri-induced skin wound repair benefits extend to human subjects. Further, dietary supplementation with a sterile lysate of this microbe alone is sufficient to boost systemic oxytocin levels and improve wound repair capacity. Oxytocin-producing cells were found to be increased in the caudal paraventricular nucleus [PVN] of the hypothalamus after feeding of a sterile lysed preparation of L. reuteri, coincident with lowered blood levels of stress hormone corticosterone and more rapid epidermal closure, in mouse models. We conclude that microbe viability is not essential for regulating host oxytocin levels. The results suggest that a peptide or metabolite produced by bacteria may modulate host oxytocin secretion for potential public or personalized health goals.

Oxytocin pathways in the intergenerational transmission of maternal early life stress

Severe stress in early life, such as childhood abuse and neglect, constitutes a major risk factor in the etiology of psychiatric disorders and somatic diseases. Importantly, these long-term effects may impact the next generation. The intergenerational transmission of maternal early life stress (ELS) may occur via pre-and postnatal pathways, such as alterations in maternal-fetal-placental stress physiology, maternal depression during pregnancy and postpartum, as well as impaired mother-offspring interactions. The neuropeptide oxytocin (OT) has gained considerable attention for its role in modulating all of these assumed transmission pathways. Moreover, central and peripheral OT signaling pathways are highly sensitive to environmental exposures and may be compromised by ELS with implications for these putative transmission mechanisms. Together, these data suggest that OT pathways play an important role in the intergenerational transmission of maternal ELS in humans. By integrating recent studies on gene-environment interactions and epigenetic modifications in OT pathway genes, the present review aims to develop a conceptual framework of intergenerational transmission of maternal ELS that emphasizes the role of OT.

Neuropeptide Regulation of Social Attachment: The Prairie Vole Model

Social attachments are ubiquitous among humans and integral to human health. Although great efforts have been made to elucidate the neural underpinnings regulating social attachments, we still know relatively little about the neuronal and neurochemical regulation of social attachments. As a laboratory animal research model, the socially monogamous prairie vole (Microtus ochrogaster) displays behaviors paralleling human social attachments and thus has provided unique insights into the neural regulation of social behaviors. Research in prairie voles has particularly highlighted the significance of neuropeptidergic regulation of social behaviors, especially of the roles of oxytocin (OT) and vasopressin (AVP). This article aims to review these findings. We begin by discussing the role of the OT and AVP systems in regulating social behaviors relevant to social attachments, and thereafter restrict our discussion to studies in prairie voles. Specifically, we discuss the role of OT and AVP in adult mate attachments, biparental care, social isolation, and social buffering as informed by studies utilizing the prairie vole model. Not only do these studies offer insight into social attachments in humans, but they also point to dysregulated mechanisms in several mental disorders. We conclude by discussing these implications for human health. © 2017 American Physiological Society. Compr Physiol 7:81-104, 2017.

The neurobiology of pair bond formation, bond disruption, and social buffering

Enduring social bonds play an essential role in human society. These bonds positively affect psychological, physiological, and behavioral functions. Here, we review the recent literature on the neurobiology, particularly the role of oxytocin and dopamine, of pair bond formation, bond disruption, and social buffering effects on stress responses, from studies utilizing the socially monogamous prairie vole (Microtus ochrogaster).

Oxytocin receptor DNA methylation in postpartum depression

The oxytocin receptor (OXTR) is a key regulator of stress and anxiety and may be regulated by both psychosocial risk factors and gonadal hormones, making it an attractive candidate for study in postpartum depression (PPD). The objective of this study was to investigate both serum hormone and PPD specific DNA methylation variation in the OXTR. Illumina HM450 microarray data generated in a prospective PPD cohort identified significant associations (P=0.014) with PPD in an intronic region in the OXTR located 4bp proximal to an estrogen receptor (ER) binding region. Pyrosequencing confirmed moderate evidence for an interaction of CpGs in the region with childhood abuse status to mediate PPD. These CpGs located on chr3 at positions 8810078 and 8810069 exhibited significant associations with postpartum depression scores from an independent cohort of 240 women with no prior psychiatric history. Hormone analysis suggested a PPD specific negative correlation of DNA methylation in the region with serum estradiol levels. Estradiol levels and OXTR DNA methylation exhibited a significant interaction to associate with the ratio of allopregnanolone to progesterone. Cumulatively, the data corroborate our previous hypotheses of a PPD specific increased sensitivity of epigenetic reprogramming at estrogen target genes and suggests that OXTR epigenetic variation may be an important mediator of mood relevant neuroactive steroid production.

The ties that bond: neurochemistry of attachment in voles

In socially monogamous prairie voles (Microtus ochrogaster), mating induces three primary types of behavior; namely, partner preference, selective aggression toward conspecific strangers, and bi-parental care, making this rodent an ideal model system to study sociality and underlying neurochemical mechanisms associated with monogamous mating strategies. Here, we highlight species differences in neurochemical receptor distributions associated with mating experience leading to the establishment of stable pair-bonds. Specifically, we illustrate the role of nucleus accumbens dopamine in programming the formation and maintenance of monogamous bonds and describe the role of anterior hypothalamic vasopressin in the regulation of selective aggression. We conclude by discussing recent molecular work in voles and emphasize the importance of this rodent for future research in the behavioral neurobiology field.

Oxytocin promotes functional coupling between paraventricular nucleus and both sympathetic and parasympathetic cardioregulatory nuclei

The neuropeptide oxytocin (OXT) facilitates prosocial behavior and selective sociality. In the context of stress, OXT also can down-regulate hypothalamic-pituitary-adrenal (HPA) axis activity, leading to consideration of OXT as a potential treatment for many socioaffective disorders. However, the mechanisms through which administration of exogenous OXT modulates social behavior in stressful environmental contexts are not fully understood. Here, we investigate the hypothesis that autonomic pathways are components of the mechanisms through which OXT aids the recruitment of social resources in stressful contexts that may elicit mobilized behavioral responses. Female prairie voles (Microtus ochrogaster) underwent a stressor (walking in shallow water) following pretreatment with intraperitoneal OXT (0.25mg/kg) or OXT antagonist (OXT-A, 20mg/kg), and were allowed to recover with or without their sibling cagemate. Administration of OXT resulted in elevated OXT concentrations in plasma, but did not dampen the HPA axis response to a stressor. However, OXT, but not OXT-A, pretreatment prevented the functional coupling, usually seen in the absence of OXT, between paraventricular nucleus (PVN) activity as measured by c-Fos immunoreactivity and HPA output (i.e. corticosterone release). Furthermore, OXT pretreatment resulted in functional coupling between PVN activity and brain regions regulating both sympathetic (i.e. rostral ventrolateral medulla) and parasympathetic (i.e. dorsal vagal complex and nucleus ambiguous) branches of the autonomic nervous system. These findings suggest that OXT increases central neural control of autonomic activity, rather than strictly dampening HPA axis activity, and provides a potential mechanism through which OXT may facilitate adaptive and context-dependent behavioral and physiological responses to stressors.