Sex-dependent regulation of social avoidance by oxytocin signaling in the ventral tegmental area.

It has been hypothesized that oxytocin increases the salience of social stimuli, whether the valence is positive or negative, through its interactions with the ventral tegmental area (VTA). Indeed, oxytocin neurons project to the VTA and activate dopamine neurons that are necessary for social experiences with positive valence. Surprisingly, though, there has not been an investigation of the role of oxytocin in the VTA in mediating social experiences with negative valence (e.

Alpha-melanocyte-stimulating hormone (αMSH) modulates the rewarding properties of social interactions in an oxytocin receptor-dependent manner in Syrian hamsters (Mesocricetus Auratus).

A reduction in the rewarding properties of social interactions is frequently a key contributor to neuropsychiatric disorders. Although much remains to be learned about the neural mechanisms governing social reward, numerous studies have found that oxytocin can enhance the salience of rewarding social interactions. As a result, oxytocin has been suggested as a pharmacotherapy for disorders characterized by a dampening of social motivation.

Species differences in the effect of oxytocin on maternal behavior: A model incorporating the potential for allomaternal contributions.

Oxytocin has historically been linked to processes involved with maternal behavior. However, the relative importance of oxytocin for maternal behavior widely varies among mammalian species, from indispensable to apparently nonessential. This review proposes a new model in which the relative importance of oxytocin for mothering across species is explained by an evolutionary pressure which we term "allomaternal potential", or the degree to which other conspecifics are capable and likely to assist with caregiving.

Acute administration of fluoxetine increases social avoidance and risk assessment behaviors in a sex- and social stress-dependent manner in Syrian hamsters (Mesocricetus auratus).

Most studies investigating the effects of acute administration of selective serotonin reuptake inhibitors (SSRI) on responses to social stress have been conducted with males. This is despite the fact that SSRIs remain the primary pharmacotherapy for social stress-related disorders for both sexes and that the prevalence of these disorders is twofold higher in women than in men. To determine whether acute treatment with the SSRI, fluoxetine, alters behavioral responses to social defeat stress in a sex- or social stress-dependent manner, male and female Syrian hamsters were subjected to one of three social defeat conditions: no defeat (placed into an empty resident aggressor (RA) cage), a single defeat by one RA for 15 min, or three consecutive defeats using different RAs for 5 min each.

Oxytocin receptors in the midbrain dorsal raphe are essential for postpartum maternal social and affective behaviors.

Oxytocin receptors (OTRs) in the midbrain dorsal raphe (DR; the source of most forebrain serotonin) have recently been identified as a potential pharmacological target for treating numerous psychiatric disorders. However, almost all research on this topic has been conducted on males and the role of DR OTRs in female social and affective behaviors is mostly unknown. This may be particularly relevant during early motherhood, which is a time of high endogenous oxytocin signaling, but also a time of elevated risk for psychiatric dysfunction.

Estrogen Withdrawal Increases Postpartum Anxiety via Oxytocin Plasticity in the Paraventricular Hypothalamus and Dorsal Raphe Nucleus.

Background: Estrogen increases dramatically during pregnancy but quickly drops below prepregnancy levels at birth and remains suppressed during the postpartum period. Clinical and rodent work suggests that this postpartum drop in estrogen results in an estrogen withdrawal state that is related to changes in affect, mood, and behavior. How estrogen withdrawal affects oxytocin (OT) neurocircuitry has not been examined.

Oxytocin receptor expression in the midbrain dorsal raphe is dynamic across female reproduction in rats.

Central oxytocin receptor (OTR) expression is extremely sensitive to circulating steroid hormones and OTRs influence many of the neurobehavioural adaptations associated with female reproduction (e.g., postpartum caregiving, aggression, cognition, affective responses).

Decreased mesolimbic dopaminergic signaling underlies the waning of maternal caregiving across the postpartum period in rats.

Rationale: Mesolimbic dopamine (DA) signaling is essential for the high maternal caregiving characteristic of the early postpartum period, but little is known about dopamine's role in the expression of maternal caregiving thereafter.

Objectives: We tested the hypothesis that decreased mesolimbic dopaminergic signaling is particularly responsible for the natural decline in maternal caregiving that occurs as the postpartum period progresses.

Methods: Sprague-Dawley (SD) mother rats received intraperitoneal injections of either vehicle, the DA D1 receptor agonist SKF38393, the DA D2 receptor agonist quinpirole, or both agonists twice daily from postpartum days 9 to 15.

Sex-dependent effects of social isolation on the regulation of arginine-vasopressin (AVP) V1a, oxytocin (OT) and serotonin (5HT) 1a receptor binding and aggression.

It is widely held that social isolation produces higher rates of mortality and morbidity and has deleterious effects on an individual's sociality. Relatedly, it is widely observed that socially isolated adult rodents display significantly higher levels of aggression when placed in a social situation than do their conspecifics living in social groups. In the following study, we investigated the effects of social isolation on several neurochemical signals that play key roles in the regulation of social behavior in adults.