Showing papers on "Social stress published in 2004"

Delayed effects of chronic variable stress during peripubertal-juvenile period on hippocampal morphology and on cognitive and stress axis functions in rats

Abstract: Animal studies on the effects of chronic variable stress during the peripubertal-juvenile period on hippocampal structure and function are lacking. Twenty-eight-day-old Sprague-Dawley rats were subjected to random, variable physical or social stress regimens for 4 weeks. Hippocampal volume was found to continue to grow in all lamina examined during the transition into young adulthood. Our variable physical stress paradigm led to inhibition of this growth in the CA1 pyramidal cell layer (PCL) and in the dentate gyrus-granular cell layer (DG-GCL), which reached full arrest in the CA3-PCL. Volume deficits were first observed after chronic stress exposure when 3 weeks, but not 24 h, of recovery had elapsed. Moreover, these volume deficits were associated with impairments in the Morris water-maze navigation, sustained downregulation in the basal hippocampal glucocorticoid receptor gene expression, and deficits in the shutdown of acute stress-induced corticosterone secretion. Volume changes both due to normal maturation and after chronic stress exposure were independent of neuron number. Thus, a peripubertal-juvenile chronic stress paradigm that leads to significant alterations in the limbic-hypothalamic-pituitary-adrenal axis can produce robust effects in hippocampal structure and cognitive ability, lasting into adulthood. © 2004 Wiley-Liss, Inc.

Stress, social support, and emotional distress in a community sample of pregnant women

Abstract: Emotional distress in women during pregnancy has been shown to increase the risk of adverse outcomes for women and newborns. Increasingly, assessment and management of mood and anxiety problems dur...

The interaction of stress and park use on psycho-physiological health in older adults.

Abstract: Stress can have a negative influence on psychological and physical health, particularly among older adults. However, park-based leisure experiences, can have a positive influence upon mood states, ...

Stress and the aging immune system.

Abstract: Immune functioning decreases with normal aging and with stress. Social and psychological stressors are a part of daily life and the source of life changing events. Across the lifespan, individuals encounter numerous stressors with effects that accrue at sundry rates due to differential stress exposure, differential stress buffering, differential stress reactivity, differential stress duration (recovery), and differential restorative processes. Research on stress in older adults provides evidence that these processes contribute to effects that mimic, exacerbate, and possibly accelerate the effects of aging on immunity.

Relationship of social support and social burden to repeated breast cancer screening in the women's health initiative.

Abstract: Direct and interactive effects of social support, social burden (caregiving, negative life events, and social strain), education, and income on repeated use of breast cancer screening among a large (N=55,278), national sample of postmenopausal women participating in the Women's Health Initiative observational study were examined. Repeated screening decreased as emotional/informational support and positive social interactions decreased (ps<.01). Repeated mammography decreased with frequent caregiving (p<.01). Less social strain reduced the frequency of repeated breast self-examinations (BSEs; ps<.01), but frequent caregiving and more negative life events increased repeated use of BSE (ps<.01). Interactive effects suggested that emotional/informational but not tangible support is associated with repeated mammography and clinical breast examinations (ps<.01) and may be particularly important among low-income older women, especially those burdened by caregiving.

Borderline Personality Features and Instability of Daily Negative Affect and Self-Esteem

Abstract: We used a daily process design and multilevel modeling to examine the role of borderline personality features in the day-to-day stability of college students' negative affect and self-esteem and their reactivity to interpersonal stressors. At the end of each day for two weeks, students completed a checklist of daily stressors and measures of state affect and self-esteem. We predicted that high scores on a measure of borderline features would be related to more daily interpersonal stressors, greater negative affective and self-esteem reactivity to these stressors, and less day-to-day carryover of negative mood and self-esteem. The first and third hypotheses were supported, but not the second. The findings demonstrate the utility of a daily process methodology and multilevel modeling to study the day-to-day functioning of individuals with borderline features.

Cross-cultural equivalence of coping and involuntary responses to stress in Spain and the United States

Abstract: The cross-cultural equivalence of coping and involuntary responses to social stress was tested using confirmatory factor analysis of the Responses to Stress Questionnaire in samples of 421 Spanish and 322 American college students. The fit of a coping model, consisting of primary control engagement, secondary control engagement, and disengagement factors, was confirmed in each sample, along with the fit of an involuntary response model, consisting of engagement and disengagement factors. However, factor loadings for primary control engagement coping differed across samples, as did mean levels of stress, coping, and involuntary responses to stress. Implications for understanding the nature of coping and involuntary responses to stress across cultures are highlighted.

Effects of chronic psychosocial stress on cardiac autonomic responsiveness and myocardial structure in mice.

Abstract: Repeated single exposures to social stressors induce robust shifts of cardiac sympathovagal balance toward sympathetic dominance both during and after each agonistic interaction. However, little evidence is available regarding possible persistent pathophysiological changes due to chronic social challenge. In this study, male CD-1 mice (n = 14) were implanted with a radiotelemetry system for electrocardiographic recordings. We assessed the effects of chronic psychosocial stress (15-day sensory contact with a dominant animal and daily 5-min defeat episodes) on 1) sympathovagal responsiveness to each defeat episode, as measured via time-domain indexes of heart rate variability (R-R interval, standard deviation of R-R interval, and root mean square of successive R-R interval differences), 2) circadian rhythmicity of heart rate across the chronic challenge (night phase, day phase, and rhythm amplitude values), and 3) amount of myocardial structural damage (volume fraction, density, and extension of fibrosis). This study indicated that there was habituation of acute cardiac autonomic responsiveness, i.e., the shift of sympathovagal balance toward sympathetic dominance was significantly reduced across repeated defeat episodes. Moreover, animals exhibited significant changes in heart rate rhythmicity, i.e., increments in day and night values and reductions in the rhythm amplitude, but these were limited to the first 5 days of chronic psychosocial stress. The volume fraction of fibrosis was sixfold larger than in control animals, because of the appearance of many microscopic scarrings. In summary, although mice appeared to adapt to chronic psychosocial stress in terms of acute cardiovascular responsiveness and heart rate rhythmicity, structural alterations occurred at the myocardial level.

Behavioural and neuroendocrine adaptations to repeated stress during puberty in male golden hamsters.

Abstract: In adult animals, the consequences of stress are often severe and long lasting. Repeated subjugation in adult male golden hamsters inhibits aggression and increases submissive and avoidant behaviours. By contrast, subjugation during puberty enhances offensive aggression. The goals of this study were to characterize behavioural and neuroendocrine responses of nao¨ve and repeatedly subjugated juveniles to social defeat and to assess potential recovery from social stress. From the onset of puberty on postnatal day 28 (P28) to mid puberty (P42), animals were either socially subjugated or placed in a clean and empty cage for 20 min daily. The subjugated and control groups were further divided into subgroups and sacrificed under basal conditions or after social defeat on P28, P35 (early puberty), P45 (mid puberty) and P70 (early adulthood). On P35 and P45, repeatedly subjugated juveniles showed a complete inhibition of olfactory investigation (i.e. risk assessment) towards aggressive adults. Repeatedly subjugated animals also had lower postdefeat cortisol levels than controls on P45. Interestingly, basal cortisol levels increased gradually during puberty but did not differ between treatment groups at any point. Repeated subjugation was also associated with increased tyrosine hydroxylase immunoreactivity (ir-TH) within the extended medial amygdala. After a 4-week recovery period, none of these variables differed between subjugated and control groups. In an additional experiment, subjugated adults also had increased ir-TH in the medial extended amygdala, suggesting that these neurones are particularly responsive to social stress. In conclusion, puberty may be a developmental period characterized by behavioural and neuroendocrine plasticity in stress responsiveness. Furthermore, peri-pubertal changes in stress hormones may explain why juvenile hamsters are more resilient to social stress than adults.

Stressful Situations at Work and in Private Life among Young Workers: An Event Sampling Approach.

Abstract: Most studies on occupational stress concentrate on chronic condi- tions, whereas research on stressful situations is rather sparse. Using an event- sampling approach, 80 young workers reported stressful events over 7 days (409 work-related and 127 private events). Content analysis showed the newcomers' work experiences to be similar to what is typically found in older samples (e.g., social stressors, quantitative overload, problems of cooperation). At work and in private life, social stressors were dominant. In multilevel-analyses active coping predicted higher success in calming down and problem solving, particularly in controllable situations. Palliation was positively related to successful calming down and negatively to event-related well-being. With regard to the relationship between chronic conditions and situational variables, (stable) job control was associated with successful calming down in stressful situations, and it buffered the effect of chronic job stressors on successful situational calming down, yielding a specific variant of the demands-control model. Number of work-related stressful events, weighted by significance, was moderately associated with chronic job stressors. However, while chronic job stressors predicted momentary well-being over and above the weighted number of events, events did not predict momen- tary well-being, and its prediction of stable well-being disappeared once chronic stressors were controlled. These results show how chronic conditions represent background variables that not only have a stronger influence on well-being but also influence the immediate reaction to stressful encounters.

Repeated sensory contact with aggressive mice rapidly leads to an anticipatory increase in core body temperature and physical activity that precedes the onset of aversive responding.

Abstract: The present study investigated whether the 'psychological threat' induced by sensory contact with an aggressive conspecific would be a sufficient factor in inducing behavioural and physiological disturbances. Repeated sensory contact with an aggressive mouse (social threat) in a partitioned cage was compared with repeated exposure to a novel partitioned cage in male NMRI mice. We first examined parameters of stress responsiveness (body weight, plasma corticosterone levels, frequency of self-grooming and defecation). The temperature and physical activity responses to stress were also recorded during and after the 4 weeks of stress using radiotelemetry. Finally, cognitivo-emotional performance was assessed after acute stress and 2 and 4 weeks of stress by measuring decision making, sequential alternation performance and behaviour in the elevated T-maze. Social threat had a greater impact than novel cage exposure on most parameters of stress responsiveness, although mice did not habituate to either stressor. Social threat rapidly led to an anticipatory rise in core body temperature and physical activity before the scheduled stress sessions. Such anticipation developed within the first week and persisted for 9 days after ending the stress procedure. Some memory impairment in the sequential alternation test was found in stressed mice, independent of the stressor. After 4 weeks of stress, inhibitory avoidance in the elevated T-maze was enhanced in socially stressed mice and reduced in novel cage mice. The sustained anticipation of stress in the social threat group preceded aversive responding. It remains to be established whether anticipation contributes to the development of aversive responses.

Modeling the effects of stressors on the performance of populations of pigs.

Abstract: A simulation model that predicts the effect of the social, physical, and nutritional environments on pig food intake and performance was extended to deal with individual variation. The aim was to investigate the effect of between-animal variation on the performance of a population of growing pigs. Variation was generated in initial state, growth potential, and ability to cope when exposed to social "stressors" (EX). Variation in initial state is described by initial body weight (BW0), from which the chemical composition of the pig is calculated. Variation in growth potential is described by creating variation in the genetic growth descriptors. Variation in EX exists between genotypes, where it has been suggested that leaner, more modern genotype pigs tend to be less able to cope. It is expected that within a population or group that the social environment (i.e., position within the social hierarchy) also affects an individual's ability to cope. In the model, it is assumed that the larger, more dominant individuals are better able to cope when exposed to social stressors. Consequently, within a population, EX is correlated with body weight around the genotype mean. Model predictions showed that increasing the variation in BW0 and EX increased the variation in pig performance. This is an important practical consideration in commercial pig production, where the heterogeneity of the population at slaughter may affect the profitability of an enterprise. The way a stressor constrains performance determines whether the mean population response to a given stressor is the same as the average individual response. If all pigs in a group are affected at the same stressor intensity (e.g., all are either mixed or not), then the predicted average individual and mean population responses will be the same. If, however, the intensity of stressor at which performance becomes limiting differs between individuals (such as space allowance or temperature), differences between the individual and mean population responses will be predicted. Variation in the growth response of a population was determined to a greater extent by variation in EX and BW0 than by variation in growth potential, when pigs were housed in simulated conditions likely to be encountered in commercial environments. Consequently, decreasing the variation in initial body weight and improving ability of pigs to cope may be a better way of improving pig performance than selecting only for increased growth potential.

Chronic Social Stress in the Community and Associations with Psychological Distress: A Social Psychological Perspective

Abstract: Chronic social stress is strongly related to psychological distress in vulnerable groups such as the frail elderly and ill people. Little, however, is known about these phenomena in the general population. The validity and reliability of a new brief measure, the Bergen Social Relationships Scale (BSRS), were investigated in a Norwegian county; the prevalence of chronic social stress was measured using the BSRS, and the associations of chronic social stress and social support with three measures of psychological distress were investigated. Respondents with high BSRS scores had experienced longstanding, important interpersonal relationship problems rather than fleeting stressful incidents. Women reported higher levels of chronic social stress, 60% reporting positively on at least one of the six BSRS items, compared with 50% among men. Social support was negatively and significantly associated with various measures of psychological distress. Chronic social stress was positively and significantly associated w...

Sex differences in effects of mild chronic stress on seizure risk and GABAA receptors in rats

Abstract: Social stress is a common occurrence in our society that can negatively impact health. Therefore, we wanted to study the effects of a mild stressor designed to model social stress on seizure susceptibility and GABA A receptors in male and female rats. The mild chronic stress of individual housing consistently decreased bicuculline (but not pentylenetetrazol, PTZ) seizure thresholds by 10–15% in both sexes. Housing conditions did not alter the anticonvulsant activity of diazepam or ethanol, although the anticonvulsant effect of ethanol was significantly greater against PTZ-induced seizures. Experiments testing the addition of an acute restraint stress unmasked sex differences in seizure induction. The acute stress also selectively decreased the potency of GABA to modulate GABA A receptor-mediated chloride uptake in group-housed females. There were additional sex differences by housing condition for GABA A receptor-gated chloride uptake but no differences in [ 3 H]flunitrazepam binding. We also found significant effects of sex and housing on ethanol-induced increases in corticosterone (CORT) levels. In summary, there were complex and sex-selective effects of mild chronic stress on seizure induction and GABA A receptors. Gaining a better understanding of mechanisms underlying interactions between sex and stress has important implications for addressing health concerns about stress in men and women.

[Dynamic changes of brain serotonergic and dopaminergic activities during development of anxious depression: experimental study].

Abstract: Chronic psychoemotional stress of social defeats produces development of experimental anxious depression in male mice similar to this disorder in humans. 5-HT and 5-HIAA levels, TPH and MAO A activities, 5-HT1A-receptors in different brain areas were investigated at different stages of development of experimental disorder. It has been shown that initial stage (3 days of social stress) is accompanied by increase of 5-HT level in some brain areas. Decreased 5-HIAA levels in the hippocampus, amygdala and nucleus accumbens were discovered at the stage of forming depression (10 days of social stress). Pharmacological desensitisation and decreased number of 5-HT1A-receptors were shown in frontal cortex and amygdala. At the stage of pronounced depression (20 days of stress), there were no differences in 5-HT and 5-HIAA levels in all brain areas (excluding hypothalamus) of depressive animals. However increased number of 5-HT1A-receptors and decreased affinity in amygdala and decreased TPH and MAOA activities in hippocampus were found in depressive mice. Hypofunction of serotonergic system is suggested at the stage of pronounced depression state in animals. Similar processes had place in brain dopaminergic systems. It is concluded that dynamic changes of brain monoaminergic activities accompany the development of anxious depression in animals. Various parameters of monoaminergic systems are differently changed depending on brain area, mediator system and stage of disorder.

The gall of subordination: changes in gall bladder function associated with social stress

Abstract: Diverse physiological and behavioural mechanisms allow animals to effectively deal with stressors, but chronic activation of the stress axis can have severe consequences. We explored the effects of chronic social stress on agonistic behaviour and gall bladder function, a critical but widely neglected component of stress-induced gastrointestinal dysfunction. Prolonged cohabitation with dominant individuals elicited behavioural modifications and dramatically increased bile retention in subordinate convict cichlid fish (Archocentrus nigrofasciatum). The key predictor of gall bladder hypertrophy was social subordination rather than status-related differences in food intake or body size. Stress-induced inhibition of gall bladder emptying could affect energy assimilation such that subordinate animals would not be able to effectively convert energy-rich food into mass gain. These results parallel changes in gall bladder function preceding cholesterol gallstone formation in humans and other mammals. Thus, social stress may be an important diagnostic criterion in understanding pathologies associated with gall bladder dysfunction.