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.     

Nonsuicidal Self-injury,Suicide Planning,and Suicide Attempts Among High-risk Adolescents Prior to Psychiatric Hospitalization

Research on Child and Adolescent Psychopathology - The purpose of this study was to understand the trajectories of nonsuicidal self-injury (NSSI) and suicide plans (SP) in the 90 days...     

Increasing accuracy of rock-climbing techniques in novice athletes using expert modeling and video feedback

Several studies have examined the efficacy of behavior analytic coaching strategies in sports to increase performance fluency. Rock climbing is a multifaceted sport requiring mastery of several complex behavior chains in order to successfully navigate climbing surfaces. To date, most investigations have focused on the physiological aspects of rock climbing, as opposed to training specific rock-climbing movements. In this replication and extension, researchers used a multiple baseline design across skills to examine an expert video modeling plus video and verbal feedback training package on foundational rock-climbing skills of novice adult climbers. Results demonstrated that all participants showed an increase in accurate performance for all three skills that were targeted in the intervention.     

Perception of genetic risk among genetic counselors

A mailed survey of female prenatal genetic counselors, obstetric nurses, and high school biology teachers was conducted to determine if these groups hold different attitudes toward genetic risk and to investigate the extent to which any differences result from the effect of different professional experiences. In this study, the participants were 166 genetic counselors, 116 obstetric nurses, and 78 biology teachers (n = 360). Survey participants completed a written questionnaire designed to assess their numeric estimate of the empiric risk for birth defects/genetic problems, their subjective perception of this risk, and their personal use of prenatal diagnosis. Genetic counselors were found to be less likely than the other groups to consider the frequency of birth defects/genetic problems as rare and were 10 times more likely than nurses and 8 times more likely than teachers to have had prenatal diagnosis. Furthermore, more than half of the prenatal diagnosis procedures had by genetic counselors were not medically indicated. These results suggest that genetic counselors have an increased perception of genetic risks relative to nurses or teachers. Possible explanations for this finding are discussed, and the potential role of discordant risk perception in creating biases in the genetic counseling process is explored.     

Repetitive Intimate Partner Victimization: An Exploratory Application of Social Learning Theory

The research literature on intimate partner violence (IPV) has documented a number of poignant facts that serve as the foundation for this study. First, IPV is prevalent, frequent, and often repetitive. Moreover, repetitive violence within an intimate relationship tends to escalate over time, both in its frequency of occurrence and in its severity. We also know that decisions to leave the relationship do not guarantee that the violence will end. In addition, the phenomenon of “mutual combatancy,” prevalent in many intimate partner relationships, suggests that both parties in this dyadic process co-share the roles of offender and victim. Finally, we know that targets of IPV, like their abusers, tend to disproportionately come from families-of-origin in which violence and aggression were directly and/or vicariously experienced. These facts suggest that one possible starting point for the exploration of repetitive intimate partner victimization (R-IPV) may derive from an inter-generational transmission, or cycle of violence theory, suggested more formally in social learning approaches to criminal and deviant behaviors. The present study examines the extent to which measures of Akers' social learning constructs are able to predict repetitive intimate partner victimization. Self-report data on intimate partner violence among a sample of college students reveal the social learning theory variables, differential association and differential reinforcement in particular, are able to predict both the prevalence and frequency of predict repetitive intimate partner victimization.     

Explanatory style and coping with controllable events by student-athletes

Abstract

The present study investigated the relationship between explanatory style and the appraisal and coping of 66 major college football players with respect to stressful but controllable events in the academic and the athletic domains. A path analysis showed that for controllable events, a “pessimistic” explanatory style-in which bad events are attributed to internal, stable, and global causes-predicted appraisals of adequate resources to cope with demands, which in turn predicted increased attempts to cope.     

Shifting resources to recognize a forming object: Dependencies involving object properties

These experiments indicate that when the eyes and attention are allowed to shift to identify a newly appearing object, the success of the shift depends on properties of the object. Observers attempted to identify a parafoveal target that was followed by a mask. On many trials a prime (cue) was presented immediately before the target. The prime was a group of elements (vertices) that could trigger ocular or attentional shifts. Success of the shifts was measured by increases in identification accuracy relative to a no-prime condition (facilitation effects). Facilitation was high for many primes, but decreased systematically toward zero when the prime-elements were not easily related to form a convex object and were located outside the boundaries of the subsequent target.