Nightmares as a Coping Mechanism for Stress

The cause of nightmares remains unclear. However, previous research suggests that stress may play a key role and that nightmares may actually serve a beneficial function. Thus, the purpose of this study was to examine the overall relationship between these two variables and assess the hypothesis that nightmares serve as a coping mechanism for stress. To accomplish these goals, a group of 412 psychology students were separated into low, medium, and high nightmare frequency groups as well as low, medium, and high nightmare intensity groups. Comparisons were then conducted for daily stressors, life stressors, social support, and coping. Most notably, this study demonstrated a positive association between nightmares and coping with stress. The overall pattern seen in the analyses reflect the significant relationship between nightmares and stress, while the finding that nightmares were positively associated with coping bolsters the supposition that nightmares may help to alleviate stress.     

Effects of Minority Stress,Group-Level Coping,and Social Support on Mental Health of German Gay Men

Objective

According to epidemiological studies, gay men are at a higher risk of mental disorders than heterosexual men. In the current study, the minority stress theory was investigated in German gay men: 1) it was hypothesized that minority stressors would positively predict mental health problems and that 2) group-level coping and social support variables would moderate these predictions negatively.

Methods

Data from 1,188 German self-identified gay men were collected online. The questionnaire included items about socio-demographics, minority stress (victimization, rejection sensitivity, and internalized homonegativity), group-level coping (disclosure of sexual orientation, homopositivity, gay affirmation, gay rights support, and gay rights activism), and social support (gay social support and non-gay social support). A moderated multiple regression was conducted.

Results

Minority stressors positively predicted mental health problems. Group-level coping did not interact with minority stressors, with the exception of disclosure and homopositivity interacting marginally with some minority stressors. Further, only two interactions were found for social support variables and minority stress, one of them marginal. Gay and non-gay social support inversely predicted mental health problems. In addition, disclosure and homopositivity marginally predicted mental health problems.

Conclusions

The findings imply that the minority stress theory should be modified. Disclosure does not have a relevant effect on mental health, while social support variables directly influence mental health of gay men. Group-level coping does not interact with minority stressors relevantly, and only one relevant interaction between social support and minority stress was found. Further longitudinal or experimental replication is needed before transferring the results to mental health interventions and prevention strategies for gay men.     

Effect of Personality on Changes of Sleep Structure Caused by Emotional Stress

Effects of personality characteristics on the structure of sleep in ten normal subjects between the ages of 21–33 under stressors of various modalities were studied. Several psychological tests and polygraph recording of sleep during three nights (adaptation, background, and after emotional stress, which was modeled using the pretension level paradigm) were conducted. Statistical cluster analysis of the psychological test results revealed two groups of subjects. The first group predominantly used active coping mechanisms and was characterized by more pronounced alterations of sleep structure in response to adaptation stress (the first night in the laboratory). The second group used nonadaptation coping strategy. The sleep structure in these subjects more significantly changed in response to emotional stress.     

High self-perceived stress and many stressors, but normal diurnal cortisol rhythm, in adults with ADHD (attention-deficit/hyperactivity disorder)

Attention-deficit/hyperactivity disorder (ADHD) in adults is associated with significant impairment in many life activities and may thus increase the risk of chronic stress in everyday life. We compared adults with a DSM-IV ADHD diagnosis (n = 28) with healthy controls (n = 28) regarding subjective stress and amounts of stressors in everyday life, diurnal salivary cortisol in the everyday environment and salivary cortisol before and after cognitive stress in a laboratory setting. The association between cortisol concentrations and impulsivity was also investigated. Consistent with assumptions, individuals with ADHD reported significantly more self-perceived stress than controls, and subjective stress correlated with the amount of stressors in everyday life. The two groups were comparable with respect to overall diurnal cortisol levels and rhythm, as well as in pre- and post-stress cortisol concentrations. Post-stress cortisol (but not baseline cortisol) concentration was positively correlated with impulsivity. The group with high post-stress cortisol also reported more symptoms of depression and anxiety, as well as self-perceived stress and stressors in every-day life. The diagnosis of ADHD significantly increased the risk of belonging to the group with high post-stress cortisol levels. The results in this study warrant a focus not only on the primary diagnosis of ADHD, but also calls for a broader assessment of stressors and subjective stress in everyday life, as well as support comprising stress management and coping skills.     

哺乳动物的生理应激反应及其生态适应性

应激反应是哺乳动物的基本生理现象之一。目前,与应激有关的研究主要来自生物医学和神经内分泌学。虽然Hans Selye 提出了个体对应激的普遍性适应综合症概念,但目前的研究还主要集中于应激对个体的负效应以及与应激相关的疾病研究。然而,从进化角度似乎很难理解在数亿年的进化过程中,动物应激反应仅简单地
进化为影响个体健康并导致个体患病的一种生理过程。本文从进化的角度,综述了应激反应与动物繁殖对策的关系以及个体对环境应激源的应对类型,并阐述了动物应激反应的适应和进化意义。     

Endocrine and other responses to acute administration of cannabinoid compounds to non-stressed male calves.

There is an abundance of cannabinoid (CB) receptors for derivatives of cannabis plants in the brain and throughout the body, and several naturally occurring arachidonic acid derivatives can activate these receptors. The specific objective of this study was to activate these CB receptors in castrated male calves through administration of several CB agonists and to measure immediate changes in concentrations of several serum hormones, respiration rate, and sensitivity to pain. The rationale for the study was that exogenous activation of CB receptors might reveal whether the endogenous CB system (consisting of receptors and endogenous ligands) plays a role in the stress response of animals and specifically whether the activated CB system might be part of a coping mechanism to combat stress. Intravenous administration of three CB agonists (anandamide, methanandamide and WIN 55212-2) to nine castrated male calves under non-stress conditions provoked immediate increases of serum cortisol and respiration rate as well as rapidly caused hypoalgesia to cutaneous pain and thermal stimuli. Although anandamide and methanandamide did not affect serum prolactin, administration of another CB agonist (WIN 55212-2) did increase serum prolactin abruptly. None of the CB agonists affected serum growth hormone. In summary, many of the changes following administration of CB agonists were similar to a stress response in this species, but there were some agonist-specific differences, notably regarding prolactin secretion, as well as differences between calves and observations made in other species. Although CB receptors in calves may be activated by endogenous ligands during exposure to some stressors, the present results are also consistent with this CB system being part of a coping mechanism that helps animals deal with imposed stressors.     

Coping with an Acute Psychosocial Challenge: Behavioral and Physiological Responses in Young Women

Despite the relevance of behavior in understanding individual differences in the strategies used to cope with stressors, behavioral responses and their relationships with psychobiological changes have received little attention. In this study on young women, we aimed at analyzing the associations among different components of the stress response and behavioral coping using a laboratory psychosocial stressor. The Ethological Coding System for Interviews, as well as neuroendocrine, autonomic and mood parameters, were used to measure the stress response in 34 young women (17 free-cycling women in their early follicular phase and 17 oral contraceptive users) subjected to the Trier Social Stress Test (TSST) and a control condition in a crossover design. No significant differences in cardiac autonomic, negative mood and anxiety responses to the stressor were observed between the two groups of women. However, women in the follicular phase showed a higher cortisol response and a larger decrease in positive mood during the social stress episode, as well as greater anxiety overall. Interestingly, the amount of displacement behavior exhibited during the speaking task of the TSST was positively related to anxiety levels preceding the test, but negatively related to baseline and stress response values of heart rate. Moreover, the amount of submissive behavior was negatively related to basal cortisol levels. Finally, eye contact and low-aggressiveness behaviors were associated with a worsening in mood. Overall, these findings emphasize the close relationship between coping behavior and psychobiological reactions, as well as the role of individual variations in the strategy of coping with a psychosocial stressor.     

Effects of husbandry and management systems on physiology and behaviour of farmed and laboratory rabbits

The major issues regarding the welfare of both farmed and laboratory rabbits are reviewed, according to husbandry and management systems. The main stressors that can affect welfare and homeostatic responses in rabbits are also reviewed. An overview of the most widespread housing systems for both farmed and laboratory rabbits is presented. The main problems related to housing and management are identified, in particular those related to individual and group housing, space requirements and group size, as well as human-animal interaction. The effects of psychological and physical stressors on physiology and behaviour are illustrated through examples in various rearing conditions. Psychological stressors include social stress and fear, while physical stressors include environmental variables such as housing system and climatic factors, i.e. heat. Welfare indicators are identified that can be monitored to determine the effects of individual and environmental variables on the animals' possible coping strategies. Physiological indicators include the neuro-endocrine and psycho-neuro-immuno-endocrine measurements, while behavioural indicators include the behavioural repertoire and responses to behavioural tests. Some possible ways to enhance welfare are indicated, such as enrichment of the environment and improved handling procedures.     

Management-related stress in the red-shouldered hawk

Disturbance stress can prevent or disrupt successful management of captive birds of prey. Using heart rate as an indicator of stress, two female red-shouldered hawks (Buteo lineatus) were monitored via radio telemetry. Spontaneous heart rate fluctuations in response to stressors involved in management-related activities, as well as some in response to naturally occurring activities, were recorded. In nearly every case, stressors caused dramatic increases in the heart rate of each bird, the magnitude of which was directly related to the degree of human contact involved. The increased heart rates occurred in response to stressors whether or not any behavioral stress symptoms were exhibited. Under the conditions of this study, the use of a falconer's hood did not completely eliminate stress in restrained hawks.     

Behavioral and respiratory responses to stressors in multiple populations of three-spined sticklebacks that differ in predation pressure

Individual animals of the same species inhabiting environments which differ in the frequency and magnitude of stressors often exhibit different physiological and behavioral responses to stressors. Here, we compare the respiratory response to confinement stress, and behavioral responses to ecologically relevant challenges among sticklebacks from 11 different populations varying in predation pressure. We found that sticklebacks from high predation populations breathed faster in response to confinement stress and were, on an average, more behaviorally responsive to a pike behind glass compared with sticklebacks from low predation populations. These patterns differ from the results of studies on other species, highlighting the need for a conceptual framework to understand the proximate and ultimate factors shaping variable responses to stressors over developmental and evolutionary time. Moreover, physiological and behavioral responses were integrated with each other, both at the individual and population levels. In general, fish that were more aggressive and bold in the presence of a predator breathed faster, independent of body size. These results are consistent with the growing body of evidence that individuals differ in a suite of physiological and behavioral mechanisms for coping with challenges in the environment.     

Interaction between Varroa destructor and imidacloprid reduces flight capacity of honeybees

Current high losses of honeybees seriously threaten crop pollination. Whereas parasite exposure is acknowledged as an important cause of these losses, the role of insecticides is controversial. Parasites and neonicotinoid insecticides reduce homing success of foragers (e.g. by reduced orientation), but it is unknown whether they negatively affect flight capacity. We investigated how exposing colonies to the parasitic mite Varroa destructor and the neonicotinoid insecticide imidacloprid affect flight capacity of foragers. Flight distance, time and speed of foragers were measured in flight mills to assess the relative and interactive effects of high V. destructor load and a field-realistic, chronic sub-lethal dose of imidacloprid. Foragers from colonies exposed to high levels of V. destructor flew shorter distances, with a larger effect when also exposed to imidacloprid. Bee body mass partly explained our results as bees were heavier when exposed to these stressors, possibly due to an earlier onset of foraging. Our findings contribute to understanding of interacting stressors that can explain colony losses. Reduced flight capacity decreases the food-collecting ability of honeybees and may hamper the use of precocious foraging as a coping mechanism during colony (nutritional) stress. Ineffective coping mechanisms may lead to destructive cascading effects and subsequent colony collapse.     

Repeated thermal stressor causes chronic elevation of baseline corticosterone and suppresses the physiological endocrine sensitivity to acute stressor in the cane toad (Rhinella marina)

Extreme environmental temperature could impact the physiology and ecology of animals. The stress endocrine axis provides necessary physiological stress response to acute (day–day) stressors. Presently, there are no empirical evidences showing that exposure to extreme thermal stressor could cause chronic stress in amphibians. This could also modulate the physiological endocrine sensitivity to acute stressors and have serious implications for stress coping in amphibians, particularly those living in fragmented and disease prone environments. We addressed this important question using the cane toad (Rhinella marina) model from its introduced range in Queensland, Australia. We quantified their physiological endocrine sensitivity to a standard acute (capture and handling) stressor after exposing the cane toads to thermal shock at 35 °C for 30 min daily for 34 days. Corticosterone (CORT) responses to the capture and handling protocol were measured on three sampling intervals (days 14, 24, and 34) to determine whether the physiological endocrine sensitivity was maintained or modulated over-time. Two control groups (C1 for baseline CORT measurement only and C2 acute handled only) and two temperature treatment groups (T1 received daily thermal shock up to day 14 only and a recovery phase of 20 days and T2 received thermal shock daily for 34 days). Results showed that baseline CORT levels remained high on day 14 (combined effect of capture, captivity and thermal stress) for both T1 and T2. Furthermore, baseline CORT levels decreased for T1 once the thermal shock was removed after day 14 and returned to baseline by day 29. On the contrary, baseline CORT levels kept on increasing for T2 over the 34 days of daily thermal shocks. Furthermore, the magnitudes of the acute CORT responses or physiological endocrine sensitivity were consistently high for both C1 and T1. However, acute CORT responses for T2 toads were dramatically reduced between days 24 and 34. These novel findings suggest that repeated exposure to extreme thermal stressor could cause chronic stress and consequently suppress the physiological endocrine sensitivity to acute stressors (e.g. pathogenic diseases) in amphibians.     

出芽酵母Saccharomyces cerevisiae转录抑制因子Rdr1负调控细胞胁迫应答

Rdr1是出芽酵母Saccharomyces cerevisiae的一个转录抑制因子,参与控制细胞的多重药物耐受性,并可能与细胞胁迫应答相关．利用PCR方法扩增RDR1基因片段,将其克隆至高拷贝表达载体pYES2/NTA上并诱导Rdr1蛋白在酵母细胞中过表达．为了揭示转录抑制因子Rdr1在胁迫应答中的作用,比较了RDR1过表达细胞、RDR1缺失突变体细胞和野生型细胞在过氧化氢处理、热胁迫和高盐处理条件下的生长状态,结果显示,RDR1过表达导致细胞对上述3种胁迫作用更敏感,而RDR1缺失则使细胞对这些胁迫作用的耐受性不受影响或有一定增强．为了揭示上述不同细胞在胁迫条件下生长状态的差异与细胞内抗氧化酶活性之间的关系,测定并比较了RDR1过表达细胞、RDR1缺失突变体细胞和野生型细胞中超氧化物岐化酶(superoxide dismutase SOD)、过氧化氢酶、葡萄糖-6-磷酸脱氢酶(glucose-6-phosphate dehydrogenase G6PDH)、谷胱甘肽还原酶(glutathione reductase GR)的活性．结果表明,RDR1缺失突变体细胞具高活性的SOD、过氧化氢酶、G6PDH和GR,而Rdr1过表达细胞中SOD、过氧化氢酶、G6PDH和GR的活性较低．RDR1对SOD和过氧化氢酶活性的影响要大于G6PDH和GR．细胞抗氧化酶活性的变化初步揭示,RDR1过表达细胞对胁迫的敏感和RDR1缺失突变体细胞对胁迫耐受性增加的原因．为转录抑制因子Rdr1在胁迫应答中的负调控作用及其机理提供了初步的遗传学和生物化学证据．     

Parental stress‐coping styles affect the behaviour of rainbow trout Oncorhynchus mykiss at early developmental stages

This work examined behavioural responses in yolk‐sac rainbow trout Oncorhynchus mykiss larvae originating from strains selected for high (HR) or low (LR) plasma cortisol response to a standardized stressor. The results showed that yolk‐sac larvae originating from the HR strain were more sensitive to environmental stressors, in that they showed a shorter reaction time to low oxygen levels. Previous studies on adult and juvenile individuals from these strains demonstrated a number of correlated physiological and behavioural differences. In yolk‐sac larvae, growth and development depended mainly on internal factors, which suggest that at least some aspects of stress‐coping styles are inherent to the individual, before factors such as social experience or variable access to food resources could modify behavioural strategy.     

Involvement of corticosteroids in the processing of stressful life-events. A possible implication for the development of depression

In a sub-population of endogenously depressed patients, disturbances of the hypothalamic-pituitary-adrenal axis can be observed. Increased cortisol and CRH levels combined with normal ACTH concentrations have often been reported. Corticosteroids appear to play a role in the mood changes, in depressed subjects. However, their mechanism of action is unknown. In animal experiments, the involvement of corticosteroids in stressor-induced learning was investigated. Three paradigms were used. In the Porsolt swimtest an animal had to learn to adapt to an inescapable situation. In the lithium chloride conditioned taste aversion an animal learned to avoid sugar water. In the amphetamine sensitization a second injection of amphetamine caused a potentiated response, because of conditioning. All three conditions appeared to be stressful because they induced a corticosterone release. When adrenalectomized (ADX) mice were compared to control animals it appeared that, in all three paradigms, their memory function was disturbed. The data indicated that this was a specific glucocorticoid-mediated effect since corticosterone and dexamethasone injections were able to reverse the ADX-induced deficit. The ADX-induced disturbances were only observable at moderate stress levels. More severe stressor (lower water temperature in the Porsolt swimtest, higher lithium chloride and amphetamine doses) also made ADX mice remember their previous experiences. The results suggest that corticosteroids are involved in the consolidation of stressful events and the corresponding coping responses. They play, however, only a role in the case of moderate stressors. In ADX animals no stressor-induced corticosterone increase can occur and therefore these animals only remember severe stressors. In a depressed patient basal steroid levels are increased and consequently very mild stressors, which induce only a small extra steroid release, will be remembered. The remembering of all these negative experiences might be of importance for the development and maintenance of the depression.     

Immediate-early genes in the cerebral mechanisms of emotional stress

Immediate-early genes (IEGs) induction is one of the primary neuronal responses to emotional stress. In experiments with different types of stressors the brain structures with the most pronounced immediate early genes expression were identified. Biochemical, physiological and genetical mechanisms of the IEGs expression in the central nervous system during emotional stress are discussed in the article. Investigation of characteristics and conditions of the IEGs induction showed that immediate early genes induction is crucial for organization of neuroendocrine and hormonal responses during emotional stress. In situations that require adaptation and learning IEGs induction in brain is especially strong. The present data permit us to think that immediate early genes participate in formation of the long-lasting circulation of the negative emotional excitation in limbic system. Animals resistant and predisposed to psycho-emotional stress have different patterns of IEGs expression in conflict situations leading to emotional stresses. Immediate-early genes induction is especially pronounced in brains of sensitive to stress individuals. It is proved that differential approach with regard to individual differences in IEGs expression is preferential in emotional stress research. Neglect of this fact has led to contradictions in results of various authors. The investigation of the IEGs properties can help to define prospective ways of the effective coping with emotional stress and prevention of its dangerous consequences.     

Effect of stress on the Schultz-Dale reaction in guinea pig aorta.

The smooth muscle of thoracic aorta from guinea pig sensitized with egg albumin (EA) produced an anaphylactic contraction when it was exposed to EA. Experiments were performed to evaluate stress effects on the anaphylactic contraction in guinea pig aortic rings. Two types of stressors were used as immunosuppressor stimuli: physical restraint and shaking of the animals. Both stressors diminished the amplitude of the Schultz-Dale contraction in aortic rings from sensitized guinea pig. The shake stress stimulus interrupted several times during each session induced higher immunosuppression in animals in which the active sensitization and the stress sessions began the same day. Severe restraint stress, prior to active immunization, also suppressed significantly the anaphylactic response. The Schulz-Dale reaction in guinea pig aorta seems to be a valuable technique to study the stress effects on the anaphylactic response.     

Improvement of Raw Sausage Fermentation by Stress-Conditioning of the Starter Organism Lactobacillus sakei

Effective growth and high acidification activity during meat fermentation are key characteristics of starter lactobacilli to ensure hygienic safety and sensory quality of the product. In this study, we demonstrated that the performance of Lactobacillus sakei in sausage fermentation can be improved by preinoculation treatments with sublethal heat, cold, and salt stress. Sausages were produced and inoculated with stress-treated cells of L. sakei 23 K (pLPV111) and the isogenic mutant of the class III heat-shock repressor CtsR, which was previously shown to exhibit improved growth in fermenting sausages. The pH values of sausages fermented with stressed cells attained defined threshold values in a distinctly shorter time than those inoculated with unstressed cells. In particular, the cold-stressed cells (4 degrees C) reduced the pH to 5.0 within approximately 40 hours compared with approximately 70 hours for untreated cells. This enhanced acidification activity of the cold-stressed cells was consistent with an increased growth rate. Growth studies in culture medium showed that stress-treated cells with improved performance did not exhibit this advantage when exposed to curing salt, one of the major stressors at the beginning of sausage fermentation. Preinoculation stress treatment is a promising way to improve the effectiveness of meat starter lactobacilli.     

5‐HTTLPR genotype potentiates the effects of war zone stressors on the emergence of PTSD,depressive and anxiety symptoms in soldiers deployed to iraq

Exposure to war zone stressors is common, yet only a minority of soldiers experience clinically meaningful disturbance in psychological function. Identification of biomarkers that predict vulnerability to war zone stressors is critical for developing more effective treatment and prevention strategies not only in soldiers but also in civilians who are exposed to trauma. We investigated the role of the serotonin transporter linked polymorphic region (5‐HTTLPR) genotype in predicting the emergence of post‐traumatic stress disorder (PTSD), depressive and anxiety symptoms as a function of war zone stressors. A prospective cohort of 133 U.S. Army soldiers with no prior history of deployment to a war zone, who were scheduled to deploy to Iraq, was recruited. Multilevel regression models were used to investigate associations between 5‐HTTLPR genotype, level of war zone stressors, and reported symptoms of PTSD, depression and anxiety while deployed to Iraq. Level of war zone stressors was associated with symptoms of PTSD, depression and anxiety. Consistent with its effects on stress responsiveness, 5‐HTTLPR genotype moderated the relationship between level of war zone stressors and symptoms of emotional disturbance. Specifically, soldiers carrying one or two low functioning alleles (S or L_G) reported heightened symptoms of PTSD, depression and anxiety in response to increased levels of exposure to war zone stressors, relative to soldiers homozygous for the high functioning allele (L_A). These data suggest that 5‐HTTLPR genotype moderates individual sensitivity to war zone stressors and the expression of emotional disturbance including PTSD symptoms. Replication of this association along with identification of other genetic moderators of risk can inform the development of biomarkers that can predict relative resilience vs. vulnerability to stress.