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 role of some definite references in linguistic integration

Definite reference increases thematic integration for semantically related sentences (DeVilliers, 1974). Therefore, definite reference should increase linguistic integration in the Bransford-Franks integrated recognition paradigm. Two recognition and two recall studies demonstrated that, if anything, indefinite reference increases linguistic integration effects, as measured by existing measures of integration. However, definite reference increases topical clustering in recall. Results cast doubt on the validity of existing measures of linguistic integration and indicate that the tally model of performance in integrated recognition tasks (Reitman & Bower, 1973) is not totally adequate, either. Results are compatible with the associative model of Anderson and Bower (1973). Topical clustering appears to be a better measure of integrated memory than are existing measures of linguistic integration. Retention of information about the propositional form in which semantically related sentences are presented and integrated memory are not necessarily incompatible.     

Emotion knowledge as a predictor of social behavior and academic competence in children at risk

Following leads from differential emotions theory and empirical research, we evaluated an index of emotion knowledge as a long-term predictor of positive and negative social behavior and academic competence in a sample of children from economically disadvantaged families ( N = 72). The index of emotion knowledge represents the child's ability to recognize and label emotion expressions. We administered control and predictor measures when the children were 5 years old and obtained criterion data at age 9. After controlling for verbal ability and temperament, our index of emotion knowledge predicted aggregate indices of positive and negative social behavior and academic competence. Path analysis showed that emotion knowledge mediated the effect of verbal ability on academic competence. We argue that the ability to detect and label emotion cues facilitates positive social interactions and that a deficit in this ability contributes to behavioral and learning problems. Our findings have implications for primary prevention.