Effects of Acute Stress or Centrally Injected Interleukin-1beta on Neuropeptide Expression in the Immune System

Acute stress stimulates the expression and release of corticotropin-releasing hormone (CRH) and arginine vasopressin (AVP) from the hypothalamus, and the pro-opiomelanocortin products beta-endorphin and ACTH from the anterior pituitary. These neuropeptides are also expressed in immune tissues, and it has been proposed that they may modulate immune responses to stress through paracrine mechanisms. We subjected rats to restraint stress or central injection of interleukin (IL)-1beta to determine whether these acute stimuli can alter the expression of neuropeptides in the spleen and thymus. Restraint stress significantly increased the contents of all these neuropeptides in thymic, but not splenic, extracts. A single icv injection of IL-1beta increased contents of CRH, AVP, ACTH and beta-endorphin in the spleens of both sham-operated and adrenalectomised (ADX) rats. IL-1beta increased thymic contents of CRH and ACTH in sham-operated rats but these increases were not observed in ADX rats. These results suggest that the effects of IL-1beta on neuropeptide expression in the spleen are independent of glucocorticoids, whereas IL-1beta stimulation of neuropeptide expression in the thymus is dependent on circulating glucocorticoids. There were significant correlations between increases in CRH, ACTH and beta-endorphin in the spleen, and between CRH and ACTH in the thymus, consistent with the suggestion that IL-1beta-induced increases in ACTH and beta-endorphin may be mediated through CRH. These results provide evidence that stressors can directly influence neuropeptide expression in immune tissues. Thus stress may influence immune functions through paracrine mechanisms involving locally synthesised neuropeptides as well as through activation of the hypothalamo-pituitary-adrenal axis.     

The Search for Employment: Motivation to Engage in a Coping Behavior1

The search for employment was examined as coping through engagement in motivated behavior. A model predicting social networking and employer contact behavior was tested with a sample of persons anticipating college graduation. Proposed relations among behavioral antecedents were primarily drawn from Ajzen's (1985) theory of planned behavior, with the addition of cognitively appraised challenge. Structural equations analysis revealed general support for hypothesized relations among attitude, norms, perceived behavioral control, intentions, and behaviors. Cognitively appraised challenge partially mediated the effects of perceived behavioral control on job search intentions. Significant variance in job search attitude was attributed to a valence by outcome expectancy interaction. Findings may be useful in promoting job search efforts, as well as furthering theoretical delineation of the search process.     

Distinctions Between Hostile and Nonhostile Forms of Perceived Criticism From Others

Criticism and hostility from others are related to fluctuations in symptom severity across many disorders, including depression and anxiety. Objective coding systems typically allow for distinctions between criticism and hostility, but the primary self-report measure of perceptions of criticism (the Perceived Criticism Measure) contains no such distinction. This report presents results from two samples regarding the assessment of specific perceptions of hostile and nonhostile criticism. In addition to these specific perceptions, we assessed relationship satisfaction, perceptions of overall criticism, and symptoms of depression and anxiety. Perceptions of hostile criticism were similar to ratings of overall criticism, as indicated by a positive correlation between these two and similar correlations with related variables. In contrast, perceptions of nonhostile criticism demonstrated more complex patterns of associations, showing a positive correlation with relationship satisfaction, a negative correlation with perceptions of hostile criticism, and a positive association with general perceptions of criticism only in the context of low depressive symptoms (as depressive symptoms increased, this association became significantly weaker). These results suggest that respondents do distinguish between perceptions of hostile and nonhostile criticism, and these perceptions are not simply different points on the same continuum. Moreover, they suggest that individuals with higher levels of depression may be less likely to incorporate nonhostile criticism into their overall perceptions of criticism from others.     

Hypothalamo-Pituitary-Adrenocortical Regulation Following Lesions of the Central Nucleus of the Amygdala

Previous reports indicate that the central nucleus of the amygdala (CeA) stimulates adrenocorticotropin and corticosterone secretion, suggesting a role for this region in central hypothalamo-pituitary-adrenocortical (HPA) stress regulation. To evaluate this hypothesis, this study assessed the impact of CeA lesion on the response of hypophysiotrophic paraventricular nucleus (PVN) neurons to acute restraint and chronic unpredictable stress exposure. In contrast to previous reports, CeA lesions did not affect corticosterone or ACTH secretion induced by acute stress. Acute restraint increased PVN corticotropin releasing hormone (CRH) mRNA expression, increased the number of parvocellular PVN neurons expressing the co-secretagogue arginine vasopressin (AVP), and induced cFOS mRNA expression in the parvocellular PVN. However, there was no additional effect of CeA lesion on any measure of PVN activation. Chronic unpredictable stress exposure induced long-term activation of the HPA axis, noted by thymic involution, adrenal hypertrophy and increased PVN CRH mRNA expression. Stress-induced changes in thymus and adrenal weights were not affected by CeA lesion. Further, CeA lesion rats did not differ from controls in post-stress CRH mRNA expression. However, basal CRH mRNA expression was increased in the PVN of CeA rats, suggesting that the CeA plays a role in long-term inhibition of the PVN. The results of these studies are not consistent with the hypothesis that the CeA is necessary for stress-induced pituitary-adrenocortical activation. Rather, this region may play a stressor-specific modulatory role in regulation of HPA function.     

Personality traits as moderators of the associations between deployment experiences and PTSD symptoms in OEF/OIF service members

Abstract

This investigation examined traits from the five-factor model of personality as moderators of the associations of combat and aftermath of battle experiences with symptoms of posttraumatic stress disorder (PTSD) in 214 National Guard/Reserve service members deployed to operations enduring and Iraqi freedom. Extraversion significantly moderated the associations of both combat experiences and aftermath of battle experiences with PTSD severity, with associations weakening as levels of extraversion increased. The relation between aftermath of battle experiences and PTSD was also moderated by the other four personality factors, with the relation being weaker at higher levels of agreeableness, conscientiousness, and openness, and lower levels of neuroticism. These results suggest that personality traits may impact individual responses to war trauma, particularly war-related experiences that are not directly threatening to one's safety (i.e., aftermath of battle events vs. actual combat events). Although this investigation was cross-sectional, these findings indicate that personality traits are an important risk/resiliency factor to consider in people's responses to traumatic events.     

Relationship distress in partners of combat veterans: the role of partners' perceptions of posttraumatic stress symptoms

Partners of combat veterans with posttraumatic stress disorder report elevated relationship and psychological distress, but little is known about the mechanisms by which such distress develops. In two separate samples, we examined partners' perceptions of veterans' PTSD symptoms, with a specific focus on the simultaneous associations of partners' distress with their perceptions of veterans' reexperiencing, withdrawal/numbing, and hyperarousal symptom clusters. The first sample consisted of 258 partners of Operation Enduring- and Iraqi Freedom-era veterans who completed questionnaires. The second sample consisted of 465 partners of Vietnam-era veterans who completed interviews as part of the National Vietnam Veterans Readjustment Study. In both samples, path analyses revealed that, when examined simultaneously, partners' perceptions of withdrawal/numbing symptoms were associated with greater distress, but perceptions of reexperiencing symptoms were unrelated to psychological distress and significantly associated with lower levels of relationship distress. Given the cross-sectional nature of the data in both samples, there are multiple plausible interpretations of the results. However, the pattern is consistent with an attributional model of partner distress, whereby partners are less distressed when symptoms are more overtly related to an uncontrollable mental illness. Potential clinical implications are discussed.