Inhibition of the LH Surge by Restraint Stress in Cyclic Rats: Studies on the Role of GABAA and GABAB Receptors

There is evidence that stress can alter the activity in the brain of gamma-aminobutyricacid (GABA), a neurotransmitter that has been implicated in the regulation of LH secretion. In the present study the role of GABA in the restraint stress-induced inhibition of the LH surge was investigated in the intact cyclic rat. Intracerebroventricular (icv) administration of the GABAA receptor agonist muscimol (0.1, 0.5 or 1 μg) 5 min before the presumed onset of the pro-oestrous LH surge (at 0900 h) caused a dose dependent suppression of the surge. A single dose of the GABAB receptor agonist baclofen (1 μg; icv) injected at 0855 h postponed the onset of the LH surge, and repeated injections at 0855 and 1130 h suppressed the surge. These data indicate that GABA-ergic activity in the brain can inhibit the LH surge in the cyclic rat via GABAA and GABAB receptors. Pro-oestrous rats were subjected to 5 hrs of restraint starting at 0855 h. Pretreatment with the GABAA receptor antagonist bicuculine (1 μg; icv) at 0840, 0940 and 1040 h or pretreatment with the GABAB receptor antagonist phaclofen (10 μg; icv) at 0840 h were ineffective in preventing the restraint-induced inhibition of the LH surge. The results suggest that GABAA and GABAB receptors are not involved in the inhibitory effect of restraint stress on the LH surge.     

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.     

Problem–Problem Solver Characteristics Affectingthe Calibration of Judgments

The purpose of this paper is to examine factors that affect the calibration of judgments by systematically comparing experts’ judgments to novices’ when solving a complex, real-world problem that varies in its initial characteristics. Calibration in this context refers to the proportion of times decision makers provide a range about their best estimates that includes the actual outcome. We found that experts specify a narrower range and provide more accurate best estimates than novices. But their tighter ranges are not justified by their greater accuracy: they are less likely to encompass the actual outcome than are novices. However, this effect is attenuated when solving more complex problems. Novices apparently underestimate the complexity of difficult problems, hence the accuracy of their best estimates decreases as does the width of their ranges, resulting in worse calibration. The performance of experts was not significantly different across problem solving conditions. Both groups provided asymmetrical ranges about their best estimates, which suggests they account for the effect of subproblem dependencies.     

Cognitive changes associated with social skills training

Changes in locus of control and self-esteem during social skills training and at 6 month follow-up were investigated. Forty-four adolescent, male offenders were randomly assigned to a social skills training, attention-placebo, or no-treatment control procedure. The results showed that pre- to post-training increases in self-esteem were produced for both the social skills training and attention-placebo control groups, but not for the no-treatment control group. These increases did not continue during the follow-up phase; the social skills training group, which showed the greatest improvement during training, displayed a decrease in self- esteem during follow-up.The locus of control measures showed a statistically significant shift towards internality for the social skills training group during training, which was not found for the attention-placebo and no-treatment controls. During the follow-up phase, all three groups showed a statistically significant shift towards externality, suggesting a tendency for boys to view their behaviour and consequences as being under the control of chance factors or powerful others, during institutionalization. This effect was partly reversed during training for the social skills training group, but the effect was not long lasting. It seems therefore that social skills training is effective in producing an increase in self-esteem and a shift towards internal locus of control. These changes are, however, of short duration and the self-esteem shift may be the result of increased staff contact or other non-specific therapy factors.     

A psychometric analysis of the Personal Attributes Questionnaire

The psychometric properties of the Personal Attributes Questionnaire were examined in independent samples of male and female high school students, college students, and adults. In each of the six samples a two-factor structure (masculinity/instrumentality and femininity/expressivity) paralleling the empirically derived scales was found. Additional factor analyses of negative masculine and feminine traits were reported. Discriminant analyses revealed highly significant differentiation between the sexes. The reliabilities (Cronbach alpha) of the unit-weighted scales in each sample were also satisfactory.Support for this research was provided by NASA Grant NSG 2065 (Robert L. Helmreich, Principal Investigator) and NSF Grant BNS 78-08911 (Janet T. Spence and Robert L. Helmreich, Principal Investigators). The article was prepared while the second author was a Fellow at the Center for Advanced Study in the Behavioral Sciences, with support from the Spencer Foundation, NIMH Grant 5T32MH14581-03, and the University of Texas Research Institute.     

Using the 11-item Version of the RCADS to Identify Anxiety and Depressive Disorders in Adolescents

Research on Child and Adolescent Psychopathology - The purpose of this study was to identify items from the Revised Children’s Anxiety and Depression Scale – RCADS-C/P that provided a...