Confusion and controversy in the stress field

Post-natal stress-induced endocrine and metabolic alterations in mice at adulthood involve different pro-opiomelanocortin-derived peptides

In previous investigations we added a physical stress (mild pain) to the "classical" post-natal psychological stress in male mice, and we found that this combination produced a series of dysmetabolic signs very similar to mild human type-2 diabetes. Here, for the first time we demonstrate that within this diabetes model at least two groups of signs depend on the unbalance of two different endogenous systems. Newborn male mice were daily exposed to stressful procedures for 21 days (brief mother separation plus sham injection). Other groups underwent the same procedure, and also received naloxone (Na) to block μ-δ endogenous receptors, or a phosphorothioate antisense oligonucleotide (AS) directed against pro-opiomelanocortin (POMC)-mRNA [to block adrenocorticotropin (ACTH)- and POMC-derived opioid peptides]. Adult mice which received only post-natal stress increased body weight (+7.5%), abdominal overweight (+74%), fasting glycemia (+43%), plasma corticosterone (+110%), plasma (+169%) and pituitary (+153%) ACTH levels. Conversely, hypothalamic ACTH and corticotropin-releasing hormone (CRH) were reduced (-70% and -75%, respectively). Neonatal AS administration reverted all parameters to control values. Neonatal naloxone had little or no influence on glucose, corticosterone, ACTH, CRH levels, whereas it prevented body overweight and abdominal overweight. We conclude that, within this type-2 diabetes model in male mice at least two endocrino-neurohumoral systems are damaged, one concerning the opioid system, and the other concerning HPA hormones. The use of the two drugs was of primary importance to demonstrate this statement, and to demonstrate that these two groups of signs could be defined as "separate entities" following our complex post-natal stress model.

The effect of meditation on physical and mental health in junior college students: a quasi-experimental study

BACKGROUND

Physical stress and mental stress are increasingly common phenomena in our rapidly changing and stressful modern society. Research has found meditation to produce positive and demonstrable stress reduction effects on brain and immune functions. This study is grounded in traditional Chinese philosophical mores that teach a process summarized by the keynote activities of "calm, still, quiet, consider, and get" and the potential of this process to reduce stress in adolescents.

PURPOSE

The purpose of this study was to examine the effects of meditation on the physical and mental health of junior college students.

METHODS

This research employed a quasi-experimental design. Participants included 242 freshmen from a junior college in Taiwan selected using a convenience sampling technique. Participants were then randomly separated into experimental (n = 119) and control (n = 123) groups. The project duration was 18 weeks, during which the experimental group received 2 hours of meditation treatment per week, for a total of 36 hours. Both groups completed pretest and posttest Life Adaptation Scale forms, which included questionnaires addressing information on physical and mental distress and positive and negative coping strategies. Data were analyzed using analysis of covariance.

RESULTS

Findings showed that the effect of the experiment treatment was significant when student physical and mental distress pretest scores were controlled. Physical and mental symptoms in the experimental group were lower than those in the control group.

CONCLUSIONS

Meditation can help students to adapt to life stressors. This study also provides support for traditional Chinese wisdom, which promotes meditation as one way to improve health.

Female sexual arousal disorder with and without a distress criterion: prevalence and correlates in a representative Czech sample

INTRODUCTION

Sexual medicine would benefit from large representative surveys examining the prevalence of genital female sexual arousal disorder (FSAD) symptoms (with and without the increasingly controversial distress criterion), as well as novel FSAD correlates and potential "protective" factors.

AIMS

To examine the extent to which genital FSAD symptoms, with and without a distress criterion, are associated with both historical and current aspects of sexual behavior.

METHODS

In a representative sample of the Czech population (aged 15-88), 1,000 women were asked whether they currently have impaired lubrication and vaginal swelling (and if so, if this produces marked distress or interpersonal difficulty). They provided details of vaginal orgasm (induced by penile-vaginal intercourse [PVI] without clitoral masturbation) consistency, feelings during their first PVI, estimates of their typical foreplay and PVI durations, their degree of mental focus on vaginal sensations during PVI, among other factors.

MAIN OUTCOME MEASURES

The current prevalence of FSAD with and without a distress criterion and their associations with current and antecedent sexual behaviors and responses.

RESULTS

The current prevalence of FSAD was 10.3% without, plus 7.5% with a distress criterion (which tended to be associated with more impairments than without distress). History of vaginal orgasm (odds ratio = 2.78), never masturbating (odds ratio = 2.4), not having felt pain and discomfort on first PVI (odds ratio = 2.27), and not having frequent anal intercourse are protective against FSAD with distress, but not without distress. Age (especially over 50) and inadequate focusing of mental attention on vaginal sensations during PVI are associated with increased FSAD risk both with and without distress.

CONCLUSIONS

FSAD with and without distress appear to be different entities to some extent, with the distressed group showing more long-term signs of psychosexual impairment. We suggest that FSAD with and without distress be considered two different disorders.

Hypocretin/orexin in arousal and stress

Multiple lines of evidence indicate that hypocretin/orexin (HCRT) participates in the regulation of arousal and arousal-related process. For example, HCRT axons and receptors are found within a variety of arousal-related systems. Moreover, when administered centrally, HCRT exerts robust wake-promoting actions. Finally, a dysregulation of HCRT neurotransmission is associated with the sleep/arousal disorder, narcolepsy. Combined, these observations suggested that HCRT might be a key transmitter system in the regulation of waking. Nonetheless, subsequent evidence indicates that HCRT may not play a prominent role in the initiation of normal waking. Instead HCRT may participate in a variety of processes such as consolidation of waking and/or coupling metabolic state with behavioral state. Additionally, substantial evidence suggests a potential involvement of HCRT in high-arousal conditions, including stress. Thus, HCRT neurotransmission is closely linked to high-arousal conditions, including stress, and HCRT administration exerts a variety of stress-like physiological and behavioral effects that are superimposed on HCRT-induced increases in arousal. Combined, this evidence suggests the hypothesis that HCRT may participate in behavioral responding under high-arousal aversive conditions. Importantly, these actions of HCRT may not be limited to stress. Like stress, appetitive conditions are associated with elevated arousal levels and a stress-like activation of various physiological systems. These and other observations suggest that HCRT may, at least in part, exert affectively neutral actions that are important under high-arousal conditions associated with elevated motivation and/or need for action.

Teaching the interrelationship between stress, emotions, and cardiovascular risk using a classic paper by Walter Cannon

Classroom discussion of the classic article by Walter B. Cannon in 1914, entitled "The emergency function of the adrenal medulla in pain and the major emotions," is an excellent tool to teach graduate students the interaction between stress, emotions, and cardiovascular function. Using this article, we are able to review important early research by Dr. Cannon, including discussion of his scientific methods and results and how they hold true today. This article outlines how this classic paper is used to allow students to explore basics principles of cardiovascular control during stress. The teaching points that are presented illustrate how students can be directed to understand the interrelationship between chronic stress and cardiovascular disease.

The effects of stress and stress hormones on human cognition: Implications for the field of brain and cognition

In this review, we report on studies that have assessed the effects of exogenous and endogenous increases in stress hormones on human cognitive performance. We first describe the history of the studies on the effects of using exogenous stress hormones such as glucocorticoids as anti-inflammatory medications on human cognition and mental health. Here, we summarize the cases that led to the diagnosis of glucocorticoid-induced 'steroid psychosis' in human populations and which demonstrated that these stress hormones could thus cross the blood-brain barrier and access the brain where they could influence cognition and mental health. We then summarize studies that assessed the effects of the exogenous administration of glucocorticoids on cognitive performance supported by the hippocampus, the frontal lobes and amygdala. In the second section of the paper, we summarize the effects of the endogenous release of glucocorticoids induced by exposure to a stressful situation on human cognition and we further dissociate the effects of emotion from those of stress on human learning and memory. Finally, in the last section of the paper, we discuss the potential impact that the environmental context to which we expose participants when assessing their memory could have on their reactivity to stress and subsequent cognitive performance. In order to make our point, we discuss the field of memory and aging and we suggest that some of the 'age-related memory impairments' observed in the literature could be partly due to increased stress reactivity in older adults to the environmental context of testing. We also discuss the inverse negative correlations reported between hippocampal volume and memory for young and older adults and suggest that these inverse correlations could be partly due to the effects of contextual stress in young and older adults, as a function of age-related differences in hippocampal volume.

A Single-Bead Analysis on a Disk-shaped Microfluidic Device Using an Antigen-immobilized Bead

A disk-shaped microfluidic device (lab-on-a-Disk) was developed to allow the evaluation of mental stress. As a standard sample, secretory immunoglobulin A (sIgA), which is a candidate marker of mental stress, was measured by a heterogeneous enzyme immunoassay (EIA) on the lab-on-a-Disk. Centrifugal force provided a microfluidic control on the lab-on-a-Disk. We examined the relationship between the rotational speed, the channel profile, and the position of the microfluidic chambers from the center of rotation to manipulate sample solutions into each reaction reservoir through microchannels sequentially, i.e., retain in a reservoir or flow into a subsequent reservoir. A single glass bead with immobilized sIgA on its surface was injected into a reservoir for a competitive antigen-antibody reaction, and applied to a specific surface in a heterogeneous assay. It is expected that the lab-on-a-Disk would be suitable for miniaturization and automation of the processes in EIA compared with a conventional EIA using a titer plate.

Relationship between Transportation Stress and Polymorphonuclear Cell Functions of Bottlenose Dolphins, Tursiops truncatus

Dolphins in a captive environment are exposed to various kinds of stresses. Handling and transportation are stressful events for terrestrial mammals, and such stress may affect immune system function and increase susceptibility to infectious diseases. The same phenomenon could occur in dolphins, however, few studies have reported this in dolphins. The objective of this study was to evaluate the relationship between stress and polymorphonuclear (PMN) cell function of dolphins during transportation. Four bottlenose dolphins (Tursiops truncatus) were transported for 6 hr by truck. Serum cortisol levels, leukograms, phagocytosis, and superoxide production of PMN cells were evaluated during handling and transportation compared to resting values. The mean serum cortisol level was significantly increased during handling and transportation (p<0.05) when compared with the resting values. White blood cell (WBC) counts, eosinophil counts, phagocytosis, and superoxide production of PMN cells during handling and transportation stages decreased significantly in comparison with the resting stage (p<0.05). The concentration of serum cortisol was significantly correlated with the results of the WBC counts, eosinophil counts, superoxide production, and phagocytosis (p<0.01, p<0.05, p<0.05, and p<0.001, respectively). The present results indicate that handling and transportation are stressful events for dolphins and could affect their PMN cell functions, thereby leading to the impairment of the immune system.

d24-hour changes in circulating prolactin, follicle-stimulating hormone, luteinizing hormone and testosterone in male rats subjected to social isolation

BACKGROUND: This work analyzes the effect of social isolation (a mild stressor) on the 24-h variation of pituitary-testicular function in young Wistar rats, assessed by measuring circulating levels of prolactin, FSH, LH and testosterone. METHODS: Animals were either individually caged or kept in groups (4-5 animals per cage) under a 12:12 h light-dark cycle (lights on at 0800 h) for 30 days starting on day 35 of life. Rats were killed at 4-h intervals during a 24-h cycle, beginning at 0900 h. RESULTS: Isolation brought about a decrease in prolactin, LH and testosterone secretion and an increase of FSH secretion. In isolated rats the 24-h secretory pattern of prolactin and testosterone became modified, i.e., the maximum in prolactin seen in control animals at the beginning of the activity span was no longer detected, whereas the maximum in circulating testosterone taking place at 1700 h in controls was phase-delayed to 2100 h in isolated rats. CONCLUSION: Social isolation affects the 24-h variation of pituitary-testicular function in young rats. Secretion of prolactin, LH and testosterone decreases, and secretion of FSH increases, in isolated rats. The maximum in prolactin seen in group-caged rats at the beginning of the activity span is not observed in isolated rats. The maximum in circulating testosterone taking place at the second part of the rest span in controls is phase-delayed to the light-dark transition in isolated rats.

The impact of self-hypnosis and Johrei on lymphocyte subpopulations at exam time: a controlled study

In a prospective randomised controlled trial, 48 students were randomly assigned to stress reduction training before exams with self-hypnosis, Johrei or a mock neurofeedback relaxation control. Peripheral blood lymphocyte subpopulations and self-reported stress (Perceived Stress Scale) were measured before training and 1-2 months later as exams approached. Absolute number and percentages of CD3(+)CD4(+) and CD3(+)CD8(+) T lymphocytes, CD3(-)CD56(+) Natural Killer cells (NK cells) and NK cell cytotoxic activity was measured from venous blood. Stressed participants showed small but significant declines in both CD3(-)CD56(+) NK cell percentages and NK cell cytotoxic activity levels while CD3(+)CD4(+) T cell percentages increased, changes supported by correlations with perceived stress. The effects of stress were moderated in those who learned Johrei at exam time; 11/12 showed increases in CD3(-)CD56(+) NK cell percentages with decreased percentages of CD3(+)CD4(+) T cells, effects not seen in the relaxation control group. Stress was also buffered in those who learned and practised self-hypnosis in whom CD3(-)CD56(+) NK cell and CD3(+)CD4(+) T cell levels were maintained, and whose CD3(+)CD8(+) T cell percentages, shown previously to decline with exams, increased. The results compliment beneficial effects on mood of self-hypnosis and Johrei. The results are in keeping with beneficial influences of self-hypnosis and provide the first evidence of the suggestive value of the Japanese Johrei procedure for stress reduction, which clearly warrants further investigation.

The impact of stress on addiction

This article will review data obtained from both clinical and preclinical investigations demonstrating that exposure to stress has a significant impact on drug addiction. The preclinical literature suggests that stress increases reward associated with psychomotor stimulants, possibly through a process similar to sensitization. While it is not conclusive that a similar process occurs in humans, a growing clinical literature indicates that there is a link between substance abuse and stress. One explanation for the high concordance between stress-related disorders and drug addiction is the self-medication hypothesis, which suggests that a dually diagnosed person often uses the abused substance to cope with tension associated with life stressors or to relieve symptoms of anxiety and depression resulting from a traumatic event. However, another characteristic of self-administration is that drug delivery and its subsequent effects on the hypothalamo-pituitary-adrenal (HPA) axis are under the direct control of the individual. This controlled activation of the HPA axis may result in the production of an internal state of arousal or stimulation that is actually sought by the individual (i.e., the sensation-seeking hypothesis). During abstinence, exposure to stressors or drug-associated cues can stimulate the HPA axis to remind the individual about the effects of the abused substance, thus producing craving and promoting relapse. Continued investigations into how stress and the subsequent activation of the HPA axis impact addiction will result in the identification of more effective and efficient treatment for substance abuse in humans. Stress reduction, either alone or in combination with pharmacotherapies targeting the HPA axis may prove beneficial in reducing cravings and promoting abstinence in individuals seeking treatment for addiction.

The association between psychological distress and musculoskeletal symptoms experienced by Chinese high school students

STUDY DESIGN

A cross-sectional nonexperimental study.

OBJECTIVES

To determine the prevalence of musculoskeletal symptoms during a 6-month period and explore the contributing factors associated with these symptoms in Chinese senior class high school students. We also explored the relationship between psychological distress and musculoskeletal symptoms in this population.

BACKGROUND

Musculoskeletal symptoms with no underlying identifiable pathology are a management puzzle to medical professionals. Finding the prevalence of musculoskeletal symptoms is the first step in the prevention of further chronic pain syndromes in young adults. No study, however, has directly measured the prevalence of musculoskeletal symptoms in this population. Investigations of the contributing factors to these symptoms, though rare, can provide information to assist in the prevention of further injuries.

METHODS

The Musculoskeletal Symptom Questionnaire (MSQ) and the 12-question version of the Chinese Health Questionnaire (CHQ-12) were randomly distributed to students (n = 550) in 4 different high schools in the Tainan area of Taiwan. Of these, 471 students returned the questionnaires for analysis. Descriptive statistics were computed for means, standard deviations, and frequencies. Chi-square statistics were used for analysis of the association between psychological distress and musculoskeletal symptoms.

RESULTS

The most frequent complaints of musculoskeletal symptoms among the adolescent Chinese student population were reported as being located in the following anatomical areas: neck (56%), shoulder (45%), and back (37%). Based on the results from the CHQ-12, all of the participants were divided into 2 groups: a high psychological (CHQ-12 score > or = 5) and a low psychological (CHQ-12 score < 5) distress group. There were significant differences of prevalence of musculoskeletal symptoms between these 2 groups (P < .05), especially for the neck region (P = .003).

CONCLUSION

The results showed that the prevalence of musculoskeletal symptoms was high in this adolescent population and demonstrated a certain association with psychological distress. We suggest that surveys of this type may serve as preclinical detectors of future musculoskeletal disorders and may permit early interventions. Developing an intervention that addresses both physical and psychological problems may be beneficial for this population.

Corticosteroids: sculptors of the hippocampal formation

The influence of corticosteroids on hippocampus-dependent learning and memory processes is now indisputable. On the other hand, closer scrutiny of early studies together with interpretations from newer studies would suggest that the proposition that corticosteroid-induced hippocampal cell death accounts fully for the associated cognitive deficits is only partially correct. Firstly, it is now clear that a specific sub-population of hippocampal neurons, the granule cells of the dentate gyrus, is more sensitive to changes in the corticosteroid environment; this fact raises the interesting question of what might be the unique properties of granule cells that render them more vulnerable to these hormones, since virtually all hippocampal cells express corticosteroid receptors. Secondly, from a critical analysis of the available data, the picture that emerges is that corticosteroids, by acting through two distinct receptors, influence not only cell birth and death, but probably also cell differentiation. Mineralocorticoid receptor (MR) occupation appears to be essential for the survival of existing and newly generated granule neurons. In contrast, while glucocorticoid receptors (GR) can induce loss of neurons in the absence of MR activation, it appears that their occupation usually results in less drastic effects involving only dendritic atrophy and loss of synaptic contacts. This revised scheme of corticosteroid actions on hippocampal structure should explain earlier observations that many of the cognition- impairing effects of corticosteroids are reversible.

Illness attributions and myocardial infarction: the influence of gender and socio-economic circumstances on illness beliefs

AIM

To present findings from a study conducted between 1996 and 1998 to investigate participants' perceptions of illness causation following a myocardial infarction.

RATIONALE

The underlying assumption of many practitioners is that perceptions of illness causation will influence emotions and adjustment to illness.

DESIGN

Phenomenology was the research methodology used to examine perceptions of illness causation. A convenience sample was taken of 24 men and women who were admitted to a regional hospital in Victoria, Australia, with a provisional diagnosis of myocardial infarction. Participants were interviewed shortly after hospitalization, and interviews were taped, transcribed and thematically analysed.

FINDINGS

Stress was the most commonly cited cause of illness. Men and women demonstrated distinct differences in illness attribution. Participants who verbalized concerns about their loss of autonomy and their subsequent ability for self-management were predominantly female and uniformly members of the lowest socio-economic group

CONCLUSION

The article concludes with a discussion of implications of the findings for practice.

Stress-related eating and drinking behavior and body mass index and predictors of this behavior

BACKGROUND

Earlier studies on stress and obesity have not considered coping in situations involving stress. This study examines the associations between stress-related eating and drinking and obesity and the factors predicting this behavior. Predictive factors include risk factors for adult obesity, longitudinal socioeconomic status, and perceived social support.

METHODS

A longitudinal, population-based study of 2,359 men and 2,791 women born in 1966 in Northern Finland was conducted.

RESULTS

The body mass index at 31 years was highest among stress-driven eaters and drinkers, especially among women. Stress-driven eaters tended to eat sausages, hamburgers and pizza, and chocolate more frequently than other people. Stress-driven eaters consumed more alcohol than other people. The best predictors of stress-related eating and drinking among men age 31 years were being single or divorced, a long history of unemployment, an academic degree, and a low level of occupational education. Among women, the best predictor was a lack of emotional support.

CONCLUSION

Programs aimed at preventing and treating obesity should cover the way in which people deal with emotions, ways of achieving greater emotional support, and strategies for handling stress caused by unemployment or work.

The specificity of stress responses to different nocuous stimuli: neurosteroids and depression

The role that adrenal cortex and neurosteroid hormones may have in the etiology and/or maintenance of depressive diseases is discussed. Selye's concept of stress as the summation of unspecific body responses of the autonomic central nervous system (CNS) and hypothalamic pituitary adrenal axis (HPAA) as the main characteristic of it is contrasted with Mason's view of stress responses as being specific for different stimuli, i.e., the neuroendocrine system responds with the production of a hormonal profile individualized and characteristic for the various stimuli applied. The data reviewed provides support for Mason's interpretation of stress as fundamentally a behavioral response. In turn, the high relevance of emotional factors in the determination of stress responses led to a reconsideration of cognitive-affective interactions in nervous systems. Recent results revealed that improvement in depression treated with antidepressants (ADs) is associated with an increase in the neurosteroid 3alpha 5alpha tetrahydroprogesterone, both in the blood and cerebrospinal fluid of recovered patients. The increase occurs with both selective serotonin reuptake inhibitors and tricyclic ADs. An evaluation of the possible and putative roles for neurosteroids in the CNS is presented and suggestions for enhancing the type of supporting data from the laboratory diagnosis of depressions are advanced.

Psychosocial stressors and mammary tumor growth: an animal model

Stressful life events and the ability to cope with stress may play a role in the progression of breast cancer; however, the complex relationship between stressors and tumor growth is difficult to investigate in humans. Our studies have utilized the androgen-responsive Shionogi mouse mammary carcinoma (AR SC115) in male mice to investigate the effects of social housing condition on tumor growth rates and responses to chemotherapy. We demonstrate that, depending on social housing condition, mammary tumor growth and response to chemotherapy can both increase and decrease. We have examined the possible role(s) of 1) psychosocial variables, 2) testosterone and corticosterone, hormones altered by stress and known to stimulate SC115 cells in vivo and in vitro, 3) NK cells, one of the body's first lines of defense against tumor cells, 4) stress proteins, in mediating the differential tumor growth rates observed in our model. This review discusses the investigations we have undertaken to elucidate the mechanisms through which a psychosocial stressor, social housing condition, can alter tumor growth rate.

Stress-induced behaviors require the corticotropin-releasing hormone (CRH) receptor, but not CRH

Corticotropin-releasing hormone (CRH) is a central regulator of the hormonal stress response, causing stimulation of corticotropin and glucocorticoid secretion. CRH is also widely believed to mediate stress-induced behaviors, implying a broader, integrative role for the hormone in the psychological stress response. Mice lacking the CRH gene exhibit normal stress-induced behavior that is specifically blocked by a CRH type 1 receptor antagonist. The other known mammalian ligand for CRH receptors is urocortin. Normal and CRH-deficient mice have an identical distribution of urocortin mRNA, which is confined to the region of the Edinger-Westphal nucleus, and is absent from regions known to mediate stress-related behaviors. Since the Edinger-Westphal nucleus is not known to project to any brain regions believed to play a role in anxiety-like behavior, an entirely different pathway must be postulated for urocortin in the Edinger-Westphal nucleus to mediate these behaviors in CRH-deficient mice. Alternatively, an unidentified CRH-like molecule other than CRH or urocortin, acting through the CRH receptors in brain regions believed to mediate stress-induced behaviors, may mediate the behavioral response to stress, either alone or in concert with CRH.

Nursing Students' Stress During the Initial Clinical Experience

The purpose of this exploratory longitudinal study was to identify nursing students' perceptions of stress in their initial clinical experiences in a hospital setting. Guided by the relational view of stress, a Nursing Student's Stress Scale (NSSS) was developed to include six subscales: adequate knowledge, close supervision, averse sights, causing pain, insufficient resources, and reality conflict. The NSSS was administered three times during the clinical experience to 46 nursing students. Results showed significant differences between the students' preclinical expected stress levels and the actual levels of stress in the clinical setting. Theoretical, methodological, and practical implications of the findings are discussed. Nurse educators are encouraged to acknowledge students' perceptions of stressful situations as a basis for stress reduction intervention. Students must first cope with their own stress in the clinical reality before being expected to deal with patients' stress.

Natural steroids counteracting some actions of putative depressogenic steroids on the central nervous system: potential therapeutic benefits

Psychological similarities in the symptomatology of Cushing's and depressive diseases led to repeated attempts of treatment of the affective disease by suppression of adrenocortical secretion. While successful in many patients, all drugs employed-metyrapone, ketoconazole and aminoglutethimide-carry the danger of inducing adrenal insufficiency. In addition, their undesirable side effects were also a main reason for treatment suspension. In our 1990 proposal for the treatment of depression through control of adrenal steroid levels, we set as one of the goals the identification of steroids which can antagonize each other on their effects on the central nervous system. Specifically, we looked first at steroids that could counter each other's effects on long-term potentiation, a putative memory mechanism in the central nervous system. One reason for this was the consensus that memory mechanisms are affected in both Cushing's and depressive patients. Another was the fact that cortisol-type hormones which underlie, at least in part, the depressogenic actions of adrenal steroids also have inhibitory effects on LTP. We conjectured, then, that a steroid with opposite effects, one that could enhance long-term potentiation and, further, that could counter the depressant effects of corticosterone on long-term potentiation, could be of use in the treatment of depression. Dehydroepiandrosterone sulfate increases long-term potentiation in a dose-related manner, and preliminary data suggest that it also counteracts the depressant effects of corticosterone on long-term potentiation when injected simultaneously on experimental animals. Potentially at least, rather than resort to total suppression of adrenocortical activity, it may be possible to treat depression just by counteracting some of the effects of cortisol-like hormone actions in the central nervous system. Further, both in clinical trials as well as in experimental animals, dehydroepiandro-sterone sulfate has been shown to enhance performance in memory-requiring tasks.

Definitions of stress and sympathetic neuronal responses

1. The precise physical definitions of stress as a force per unit area and of strain as the deformation of a solid subjected to that force are conceptually similar to the demands placed upon living organisms and the responses of organisms to those demands. 2. Cannon recognized that a "breaking strain" at a "critical stress" level can overwhelm homeostatic mechanisms and suggested that such a state is signaled by appearance of "secondary, irrelevant effects." The primary mechanisms of maintaining homeostasis are highly specific; and compensatory responses are mediated by the autonomic nervous system, and the less specific responses are mediated by the adrenal medullary hormone, epinephrine. 3. Selye extended this concept to include other hormonal responses, particularly of the hypothalamic-pituitary-adrenal axis, as components of a stereotypic response common to all stresses. He redefined stress as a state in which this stereospecific response has been evoked and popularized the notion that a variety of diseases are produced as a result of excessive or deficient adaptive processes during the stress response. 4. Both Cannon and Selye recognized that the responses to stresses differ among individuals and that such differences are due to genetic differences as modified by experience (Selye called these "conditioning factors"). Both attributed highly specific homeostatic responses to nervous control and both recognized that hormonal responses are necessarily less specific than neuronal responses. 5. Selye's concept of a single stereotypic syndrome that results from any demand upon the body, however, needs to be modified to reflect differences in the pattern of responses to various stresses. Data on responses to several stresses show that when homeostatic mechanisms do not predominate, the pattern of nonspecific, particularly hormonal, responses may differ among stresses. The essential fact, however, that most demands upon the body, when exceeding a critical level, elicit an array of complex neuroendocrine responses, and that these responses may have harmful effects, remains a landmark contribution.

[Occupation and hypertension]

Scientific reports on Arterial Blood Hypertension for the period from 1970 to 1989 are reviewed, with special reference to its epidemiological focusing among workers. The knowledge gained and the theoretical and methodological advances associated with it are assessed.

Evidence for two different afferent pathways carrying stress-related information (noxious and amygdala stimulation) to the bed nucleus of the stria terminalis

The bed nucleus of the stria terminalis (BNST) is an important nucleus involved in mediating amygdala-regulated endocrine effects. Since the amygdala is important in mediating the endocrine response to noxious somatosensory stimuli and olfactory stimulation, this experiment studies whether noxious input (tail pinch, TP) and stress-related input (amygdala stimulation, AmygS) will modulate BNST neuronal activity. One hundred and fifty-eight BNST neurons were studied following AmygS, TP and cutaneous stroke. AmygS was effective in 66% of BNST neurons and produced one of the following five responses: oligosynaptic excitation (43%), polysynaptic excitation (5%), time-locked inhibition (4%), generalized increase in firing rate (8%), or generalized decrease in firing rate (6%). TP produced an increase in firing rate in 27% of BNST neurons tested. Analysis of a contingency table constructed to determine the degree of correspondence between neurons responsive to AmygS and neurons responsive to TP showed that the distributions of reactivity to these stimuli in BNST neurons are independent of each other. This suggests that although AmygS and TP are both capable of altering the firing rate of BNST neurons, the pathways by which they reach BNST differ.

Shock induces a long-lasting elevation of blood glucose in Aplysia

Glucose, and not trehalose, was found to be the main blood sugar in Aplysia californica. Changes in blood glucose in response to stress produced by electric shock were measured in blood obtained both from animals dissected within ten minutes of shocking and from catheterized animals at various intervals, up to two and a half hours after the shock. Electric shock increased blood glucose levels. The rise in blood sugar continued as long as two and a half hours after shock.

Restraint and stimulation of bed nucleus of the stria terminalis produce similar stress-like behaviors

Restraint stress, electrical stimulation of the bed nucleus of the stria terminalis (BNST), and the combination of restraint stress and BNST stimulation were studied using a computerized animal activity monitoring system. Both restraint and the combination of restraint and BNST stimulation produced increases in locomotor, exploratory and stereotypic activity all of which returned to baseline within an hour while BNST stimulation alone also increased measurements of locomotor and exploratory behavior some of which remained elevated throughout the three-hour period of measurement. BNST stimulation also produced vigorous escape behavior and biting which were not seen with restraint alone. Thus electrical stimulation of BNST produces behavior which is qualitatively similar to the behavior produced by stress but differs in time course.

Failure of industrial noise to change the patterns of vanilmandelic acid and 17-hydroxycorticosteroids in the urine of the female weavers with hearing loss

The field experiments were undertaken on two consecutive working days on seven female weavers with noise-induced hearing loss (NIHL), and a control group of seven sewers with normal hearing. The first day, urine was collected during the shift (06:00-14:00 h) and at home (17:00-05:00 h) for measurements of 17-hydroxycorticosteroids (17-OH) levels. The following day, the procedure was repeated, but for vanilmandelic acid (VMA) analysis. No significant changes in the hormone levels were found, both concerning the different occupational noise exposure and the periods of a working day.

Psychophysiological processes of stress in chronic physical illness: a theoretical perspective

This paper proposes a theoretical framework and conceptual model for clinicians and investigators working with people who have a chronic physical illness. The framework is based upon nursing theory and classical propositions from psychology and physiology. The major premise of the model is that individuals with limited psychosocial attributes and a preponderance of unmet basic needs are more likely to perceive events as threatening and experience a maladaptive stress response, such as heightened symptoms and acute exacerbations of their illness. Conversely, those with strong attributes and a perception of need satisfaction are more likely to view events as challenging, thus avoiding symptomatic discomfort and enhancing personal growth. Implications for nursing practice and research are addressed.

The cycle of stress--a circular model for the psychobiological response to strain and stress

A circular model is presented for the stress reaction. The model is composed of four phases that follow successively one after the other. The circular model which is called the stress cycle incorporates various concepts and terminologies that traditionally have been used in the stress field. The uniqueness of this stress cycle is that it will enable researchers to quantitate several parameters of the cycle such as the frequency, the amplitude and duration of the cycle. The importance of these parameters for stress management education and coping mechanisms are discussed.

A physiological analysis of stress and chronic illness

Hans Selye's theoretical propositions and empirical findings provided many of the principles currently used in stress research, and are often cited as scientific bases for nursing theory, research and practice. His General Adaptation Syndrome (GAS) has been a useful model for realizing the physiologic processes involved in the relationship between stress and acute illness, and the evolution of diseases such as cancer. The GAS can also serve as a useful paradigm for understanding the symptomatic expression and progression of a chronic physical illness, however. This paper analyses the physiologic processes of stress from this perspective, proposing that individuals with a chronic illness are at risk for experiencing acute symptomatic distress and/or exacerbations of their illness in response to stress. Specific examples involving chronic disease are cited and several additional insights gained from this approach are proposed.

Personality hardiness, occupational stress, and burnout in critical care nurses

Personality hardiness, occupational stress, and burnout were investigated in 100 critical care nurses. Hardiness was predictive of occupational stress and burnout. Hierarchical multiple regressions revealed that one of the three dimensions of hardiness, commitment to work, was the only variable to account for significant amounts of variance (up to 24%) across three of four measures of burnout. The study did not provide support for the stress buffering effect of hardiness. That is, an interaction term, hardiness x occupational stress, was not convincingly predictive of burnout in nurses. The findings are discussed in terms of other research on burnout in critical care nurses and recent issues on the conceptualization of hardiness.

Effects of daytime noise load on the sleep-wake cycle and endocrine patterns in man: II. 24 hours secretion of anterior and posterior pituitary hormones and of cortisol

The present study examines the effects of auditory stress on the plasma levels of pituitary hormones and cortisol. Each of twelve healthy male subjects participated in two experimental series; during one of them they were exposed to 85 dB(A) industrial noise from 9:00 to 21:00 h. Blood samples were taken by an indwelling venous catheter for 24 h at intervals of 20 min from 8:00 to 8:00 h. The plasma levels of ACTH, growth hormone, prolactin, oxytocin, vasopressin and cortisol were determined. In all subjects except one noise stress affected the profiles of the pituitary hormones but the responses were interindividually different. The oxytocin level was significantly elevated (p less than .01), ACTH also responded but less clearly, whereas the other hormones reacted only in individual cases. During the subsequent night sleep only PRL concentrations were elevated above the baseline plateau in several subjects. It was concluded that in humans the pituitary responses to noise stress are highly individual.

Hematological changes following repetitive decompressions during simulated extravehicular activity

A study was performed to evaluate decompression procedures suggested for use prior to Space Shuttle extravehicular activity. Hematological parameters were measured in 12 male human subjects before and after exposure in an altitude chamber to a 3-day staged decompression schedule, with simulated extravehicular activity. Following the exposure, significant increases occurred in white blood cell count and activated partial thromboplastin time, and platelet aggregate ratio was significantly decreased. Pre-exposure samples from subjects who were susceptible to formation of venous gas emboli (VGE) exhibited a significantly lower degree of ADP-induced platelet aggregation and a significantly higher amount of lymphocyte blastogenic transformation in response to the mitogen phytohemagglutinin than samples from VGE-resistant subjects. The results indicate that, following this decompression profile, small but significant changes occur in several hematological parameters, and that levels of certain parameters may be related to susceptibility to VGE formation during decompression.