Interaction of 5-HTTLPR and a variation on the oxytocin receptor gene influences negative emotionality

Variation in oxytocin receptor gene (OXTR) polymorphisms is associated with emotional and behavioral reactions to betrayal

Variations in the gene that encodes the oxytocin receptor (OXTR) have been associated with many aspects of social cognition as well as several prosocial behaviors. However, potential associations of OXTR variants with reactions to betrayals of trust while cooperating for mutual benefit have not yet been explored. We examined how variations in 10 single-nucleotide polymorphisms on OXTR were associated with behavior and emotional reactions after a betrayal of trust in an iterated Prisoner's Dilemma Game. After correction for multiple testing, one haplotype (C-rs9840864, T-rs2268494) was significantly associated with faster retaliation post-betrayal-an association that appeared to be due to this haplotype's intermediate effect of exacerbating people's anger after they had been betrayed. Furthermore, a second haplotype (A-rs237887, C-rs2268490) was associated with higher levels of post-betrayal satisfaction, and a third haplotype (G-rs237887, C-rs2268490) was associated with lower levels of post-betrayal satisfaction.

Reduced plasma oxytocin levels in female patients with borderline personality disorder

The neuropeptide oxytocin is involved in social cognition and interaction across species and plays a crucial role in the regulation of affiliative behaviors. Oxytocin levels in cerebrospinal fluid (CSF), but also in plasma or urine, have been shown to be negatively associated with childhood traumata, aggressive behavior, and suicide attempts. Recently, an altered activity of the oxytocin system has been discussed to play a prominent role in borderline personality disorder (BPD), which is thought to be closely related to traumatic experiences in childhood and is characterized by (para)suicidal behaviors as well as aggressive outbursts. In the present study, we compared plasma oxytocin levels of women with and without BPD in the follicular phase and assessed the relationship between oxytocin concentrations and childhood traumata. Women diagnosed with BPD had significantly reduced oxytocin concentrations, even after controlling for estrogen, progesterone, and contraceptive intake. In addition, plasma oxytocin correlated negatively with experiences of childhood traumata, in particular with emotional neglect and abuse. The results of mediation analyses do not support a model of oxytocin being a prominent mediator in the link between childhood trauma and BPD. Thus, the findings indicate dysregulations in the oxytocin system of patients diagnosed with BPD with more longitudinal research being necessary to disentangle the relationship between childhood adversities, oxytocin system, and psychopathology.

Spanish Validation of the Affective Neuroscience Personality Scales

The Affective Neuroscience Personality Scales have been designed to provide a personality assessment tool based on six distinct affective systems. The six neural systems involved were labeled PLAY, SEEK, CARE, FEAR, ANGER and SADNESS. Spirituality has been integrated into the questionnaire as a seventh dimension because, in opinion of Panksepp and his colleagues is one of the most interesting human emotion. The aim of the present paper was introduce the validation of the Spanish version of Affective Neuroscience Personality Scales and their first psychometric results in a sample of 411 college students. Participants completed the Spanish version of ANPS, just as a personality scale of five factors (NEO-FFI-R), and the Scales of Positive and Negative Affect (PANAS). The factor structure obtained and psychometric properties of the scales indicate that the Spanish version of the scales provides an effective tool to measure the seven dimensions of personality proposal in the original questionnaire.

Sex, receptors, and attachment: a review of individual factors influencing response to oxytocin

As discussed in the larger review in this special issue (MacDonald and Feifel), intranasal oxytocin (OT) is demonstrating a growing potential as a therapeutic agent in psychiatry. Importantly, research suggests that a variety of individual factors may influence a person's response to OT. In this mini-review, I provide a review of three: (1) sex and hormonal status; (2) genetic variation in aspects of the OT system (i.e., OT receptors); and (3) attachment history. Each of these factors will be important to monitor as we strive to develop a richer understanding of OT's role in human development, brain-based disease, and the potential for individualized, OT-targeted treatments.

Integrative approaches utilizing oxytocin to enhance prosocial behavior: from animal and human social behavior to autistic social dysfunction

The prevalence of autism spectrum disorder (ASD) is as high as 1 in 100 individuals and is a heavy burden to society. Thus, identifying causes and treatments is imperative. Here, we briefly review the topics covered in our 2012 Society for Neuroscience Mini-Symposium entitled "Integrative Approaches Using Oxytocin to Enhance Prosocial Behavior: From Animal and Human Social Behavior to ASD's Social Dysfunction." This work is not meant to be a comprehensive review of oxytocin and prosocial behavior. Instead, we wish to share the newest findings on the effects of oxytocin on social behavior, the brain, and the social dysfunction of ASD at the molecular, genetic, systemic, and behavior levels, in varied subjects ranging from animal models to humans suffering from autism for the purpose of promoting further study for developing the clinical use of oxytocin in treating ASD.

The role of the catechol-O-methyltransferase (COMT) gene in personality and related psychopathological disorders

This review provides a short overview of the most significant biologically oriented theories of human personality. Personality concepts of Eysenck, Gray and McNaughton, Cloninger and Panksepp will be introduced and the focal evidence for the heritability of personality will be summarized. In this context, a synopsis of a large number of COMT genetic association studies (with a focus on the COMT Val158Met polymorphism) in the framework of the introduced biologically oriented personality theories will be given. In line with the theory of a continuum model between healthy anxious behavior and related psychopathological behavior, the role of the COMT gene in anxiety disorders will be discussed. A final outlook considers new research strategies such as genetic imaging and epigenetics for a better understanding of human personality.

Oxytocin, stress and social behavior: neurogenetics of the human oxytocin system

The neuropeptide oxytocin has had key roles throughout mammalian evolution in the regulation of complex social cognition and behaviors, such as attachment, parental care, pair-bonding, as well as social exploration and recognition. Recently, studies have begun to provide evidence that the function of this neuropeptide is impaired in mental disorders associated with social deficits. In this review, we focus on the genetic mechanisms of inter-individual variation in the social neuropeptide signaling. We discuss molecular genetic studies which identified variations in specific genes contributing to individual differences in social behavior and cognition, with a focus on the gene coding for the oxytocin receptor (OXTR) emerging as a particularly promising candidate. We conclude that molecular studies are warranted to elucidate functional consequences of variants that have shown stable associations with sociobehavioral phenotypes. With regard to the variability in individual responses to oxytocin administration, we advocate the need for pharmacogenetic approaches in order to test how the efficacy of oxytocin administration is modulated by genetic variation of OXTR or other genes involved in oxytocin signaling.

Balance of brain oxytocin and vasopressin: implications for anxiety, depression, and social behaviors

Oxytocin and vasopressin are regulators of anxiety, stress-coping, and sociality. They are released within hypothalamic and limbic areas from dendrites, axons, and perikarya independently of, or coordinated with, secretion from neurohypophysial terminals. Central oxytocin exerts anxiolytic and antidepressive effects, whereas vasopressin tends to show anxiogenic and depressive actions. Evidence from pharmacological and genetic association studies confirms their involvement in individual variation of emotional traits extending to psychopathology. Based on their opposing effects on emotional behaviors, we propose that a balanced activity of both brain neuropeptide systems is important for appropriate emotional behaviors. Shifting the balance between the neuropeptide systems towards oxytocin, by positive social stimuli and/or psychopharmacotherapy, may help to improve emotional behaviors and reinstate mental health.

A link between oxytocin and serotonin in humans: supporting evidence from peripheral markers

Pharmacological studies indicate a functional interaction between the serotonergic and oxytocinergic systems. In particular, some selective serotonin (5-HT) reuptake inhibitors, such as citalopram and fluvoxamine, seem to exert part of their antidepressant effects through oxytocin (OT) release. Further, the administration of fenfluramine, a serotonergic agonist, to healthy subjects increases plasma OT levels. Interestingly, immunocytochemical and double-immunofluorescent techniques revealed a high degree of overlap between 5-HT transporter (SERT)-labeled fibers and OT-containing cells in the paraventricular and supraoptic nuclei of primate hypothalamus. These findings suggest that the influence of 5-HT on OT system might be mediated by SERT. In this study, we explored the possible existence of a link between OT and SERT in human subjects, by means of two peripheral markers, the platelet SERT, as measured by [³H]-paroxetine ([³H]-Par) binding, and plasma OT levels. As far as [³H]-Par binding parameters are concerned, the Bmax (mean ± SD, fmol/mg protein) was 1155 + 130 and the Kd (mean ± SD, nM) was 1.31 ± 0.61. The OT plasma levels (mean ± SD, pg/ml) were 1.14 ± 1.07. A significant and positive correlation was found between plasma OT levels and Kd values (correlation coefficient: r: 0.466, p = .038). This result represents the first evidence of an interaction between OT and SERT, as measured by [³H]-Par binding, at peripheral levels in humans. Given the several activities mediated by both OT and 5-HT, such a relationship might provide new perspectives and insights into psychiatric disorders and/or social relationship disturbances, as well as novel treatment strategies overcoming and/or integrating the serotonergic paradigm.

A new approach of personality and psychiatric disorders: a short version of the Affective Neuroscience Personality Scales

BACKGROUND

The Affective Neuroscience Personality Scales (ANPS) is an instrument designed to assess endophenotypes related to activity in the core emotional systems that have emerged from affective neuroscience research. It operationalizes six emotional endophenotypes with empirical evidence derived from ethology, neural analyses and pharmacology: PLAYFULNESS/joy, SEEKING/interest, CARING/nurturance, ANGER/rage, FEAR/anxiety, and SADNESS/separation distress. We aimed to provide a short version of this questionnaire (ANPS-S).

METHODOLOGY/PRINCIPAL FINDINGS

We used a sample of 830 young French adults which was randomly split into two subsamples. The first subsample was used to select the items for the short scales. The second subsample and an additional sample of 431 Canadian adults served to evaluate the psychometric properties of the short instrument. The ANPS-S was similar to the long version regarding intercorrelations between the scales and gender differences. The ANPS-S had satisfactory psychometric properties, including factorial structure, unidimensionality of all scales, and internal consistency. The scores from the short version were highly correlated with the scores from the long version.

CONCLUSIONS/SIGNIFICANCE

The short ANPS proves to be a promising instrument to assess endophenotypes for psychiatrically relevant science.

Oxytocin in schizophrenia: a review of evidence for its therapeutic effects

BACKGROUND

The suggestion that the neurohormone oxytocin may have clinical application in the treatment of schizophrenia was first published in 1972. Since then, a considerable body of research on a variety of fronts--including several recent double-blind treatment trials-has buttressed these early reports, providing support for the assertion that the oxytocin system is a promising and novel therapeutic target for this devastating malady. Herein, we review the diverse, convergent lines of evidence supporting the therapeutic potential of oxytocin in psychotic illness.

METHODS

We performed a systematic review of preclinical and clinical literature pertaining to oxytocin's role in schizophrenia.

RESULTS

Multiple lines of evidence converge to support the antipsychotic potential of oxytocin. These include several animal models of schizophrenia, pharmacological studies examining the impact of antipsychotics on the oxytocin system, human trials in patients examining aspects of the oxytocin system, and several double-blind, placebo-controlled clinical treatment trials.

CONCLUSIONS

There exists considerable, convergent evidence that oxytocin has potential as a novel antipsychotic with a unique mechanism of action. Auspiciously, based on the few chronic trials to date, its safety profile and tolerability appear very good. That said, several critical clinical questions await investigation before widespread use is clinically warranted.

Individual differences in trait anxiety are associated with white matter tract integrity in the left temporal lobe in healthy males but not females

The temporal lobe plays a major role in anxiety and depression disorders and is also of importance for trait anxiety in the non-pathological range. The present study investigates self-report data of personality dimensions linked to trait anxiety in the context of white matter tract integrity in the temporal lobes of the human brain in a large sample of N=110 healthy participants. The results show that especially in men values for fractional anisotropy of several white matter tracts in the temporal lobe of the left hemisphere correlate substantially with individual differences in trait anxiety (depending on the tract investigated between .40 and .49). The present study shows that not only data from functional magnetic resonance imaging (fMRI), but also from structural diffusion tensor imaging (DTI) provide interesting insights into the biological foundation of human personality traits.

Roles of oxytocin neurones in the control of stress, energy metabolism, and social behaviour

Oxytocin neurones are activated by stressful stimuli, food intake and social attachment. Activation of oxytocin neurones in response to stressful stimuli or food intake is mediated, at least in part, by noradrenaline/prolactin-releasing peptide (PrRP) neurones in the nucleus tractus solitarius, whereas oxytocin neurones are activated after social stimuli via medial amygdala neurones. Activation of oxytocin neurones induces the release of oxytocin not only from their axon terminals, but also from their dendrites. Oxytocin acts locally where released or diffuses and acts on remote oxytocin receptors widely distributed within the brain, resulting in anxiolytic, anorexic and pro-social actions. The action sites of oxytocin appear to be multiple. Oxytocin shows anxiolytic actions, at least in part, via serotoninergic neurones in the median raphe nucleus, has anorexic actions via pro-opiomelanocortin neurones in the nucleus tractus solitarius and facilitates social recognition via the medial amygdala. Stress, obesity and social isolation are major risk factors for mortality in humans. Thus, the oxytocin-oxytocin receptor system is a therapeutic target for the promotion of human health.

The contributions of oxytocin and vasopressin pathway genes to human behavior

Arginine vasopressin (AVP) and oxytocin (OXT) are social hormones and mediate affiliative behaviors in mammals and as recently demonstrated, also in humans. There is intense interest in how these simple nonapeptides mediate normal and abnormal behavior, especially regarding disorders of the social brain such as autism that are characterized by deficits in social communication and social skills. The current review examines in detail the behavioral genetics of the first level of human AVP-OXT pathway genes including arginine vasopressin 1a receptor (AVPR1a), oxytocin receptor (OXTR), AVP (AVP-neurophysin II [NPII]) and OXT (OXT neurophysin I [NPI]), oxytocinase/vasopressinase (LNPEP), ADP-ribosyl cyclase (CD38) and arginine vasopressin 1b receptor (AVPR1b). Wherever possible we discuss evidence from a variety of research tracks including molecular genetics, imaging genomics, pharmacology and endocrinology that support the conclusions drawn from association studies of social phenotypes and detail how common polymorphisms in AVP-OXT pathway genes contribute to the behavioral hard wiring that enables individual Homo sapiens to interact successfully with conspecifics. This article is part of a Special Issue entitled Oxytocin, Vasopressin, and Social Behavior.

Childhood aggression, callous-unemotional traits and oxytocin genes

Given the known behavior effects of oxytocin,and in particular its putative effect on trust, affiliation and anxiety, we hypothesized that oxytocin may be involved in the development and expression of callous-unemotional traits in children with aggressive antisocial behavior. We recruited 162 children between the ages of 6 and 16. The majority of subjects were Caucasian (84.0%) compared to African-Canadian (4.9%) and others (11.1%). The oxytocin and oxytocin receptor gene polymorphisms were genotyped and analyzed for possible association with child aggression in a case–control study design as well as with callous-unemotional traits in a within cases analysis. We did not have significant findings with our tested OXTR markers in the case–control analysis. We found the OXTR_rs237885 AA genotype carriers to score higher than AC or CC genotype carriers on the callous-unemotional traits. This result remained significant following correction for multiple testing. No other markers were found to be significant. However, the haplotype consisting of the OXTR_rs237885 A allele and OXTR_rs2268493 A allele was associated with significantly higher callous-unemotionals cores than other haplotypes. This is the first known study to show a significant association between callous unemotional traits in children and adolescents with extreme, persistent pervasive aggression and a polymorphism on the oxytocin receptor. Given the small sample size and the possibility of false positive effects, the need to replicate and verify these findings is required.

Ignorance is no excuse: moral judgments are influenced by a genetic variation on the oxytocin receptor gene

Perspective-taking has become a main focus of studies on moral judgments. Recent fMRI studies have demonstrated that individual differences in brain activation predict moral decision making. In particular, pharmacological studies highlighted the crucial role for the neuropeptide oxytocin in social behavior and emotional perception. In the present study N=154 participants were genotyped for a functional polymorphism (rs2268498) in the promoter region of the OXTR gene. We found a significant difference between carriers and non-carriers of the C-allele in exculpating agents for accidental harms (F((1,152))=11.49, p=.001, η(2)=.07) indicating that carriers of the C-allele rated accidentally committed harm as significantly more blameworthy than non-carriers. This is the first study providing evidence for a genetic contribution to moral judgments.

Oxytocin and vasopressin in the human brain: social neuropeptides for translational medicine

The neuropeptides oxytocin (OXT) and arginine vasopressin (AVP) are evolutionarily highly conserved mediators in the regulation of complex social cognition and behaviour. Recent studies have investigated the effects of OXT and AVP on human social interaction, the genetic mechanisms of inter-individual variation in social neuropeptide signalling and the actions of OXT and AVP in the human brain as revealed by neuroimaging. These data have advanced our understanding of the mechanisms by which these neuropeptides contribute to human social behaviour. OXT and AVP are emerging as targets for novel treatment approaches--particularly in synergistic combination with psychotherapy--for mental disorders characterized by social dysfunction, such as autism, social anxiety disorder, borderline personality disorder and schizophrenia.