Psychoneuroendocrinology
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Psychoneuroendocrinology · Jul 2006
Comparative StudyThe four-dimensional stress test: psychological, sympathetic-adrenal-medullary, parasympathetic and hypothalamic-pituitary-adrenal responses following inhalation of 35% CO2.
Hypercapnia is a threat to homeostasis and results in neuroendocrine, autonomic and anxiogenic responses. The inhalation of carbon dioxide (CO2) may, therefore, provide a good paradigm for exploring the pathways by which stress can lead to increased susceptibility to ill-health through physiological and psychological stress reactivity. The current study was designed, therefore, to assess the psychological and physiological responses to the inhalation of CO2. ⋯ Inhalation of 35% CO2 reliably stimulated the key mechanisms involved in the human stress response. The inter-individual differences in the reactivity of the hypothalamic-pituitary-adrenal axis were also related to differences in the perception of the test.
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Psychoneuroendocrinology · Feb 2006
ReviewThe effects of sex and hormonal status on the physiological response to acute psychosocial stress.
Whether one is male or female is one of the most important determinants of human health. While males are more susceptible to cardiovascular and infectious disease, they are outnumbered by women for many autoimmune disorders, fibromyalgia and chronic pain. Recently, individual differences in the physiological response to stress have emerged as a potentially important risk factor for these disorders. ⋯ The pronounced and multi-faceted sex differences in stress responsiveness suggest that they are a product of a strong evolutionary pressure. We hypothesise that this has to a great deal been driven by the need to protect the fetus from the adverse effects of maternal stress responses, in particular excess glucocorticoid exposure. Studying this hypothesis may have a fundamental impact on our understanding about how adult health is set during early life and how adult disease could be prevented in men and women.
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Psychoneuroendocrinology · Jan 2006
Randomized Controlled TrialSalivary alpha amylase as marker for adrenergic activity during stress: effect of betablockade.
Free salivary cortisol is an established non-invasive marker of hypothalamus pituitary adrenal (HPA) axis activity. In contrast, such a well-characterized salivary marker for activity of the sympatho-adrenal medullar (SAM) system is still missing. As one potential candidate salivary alpha amylase (sAA) has been suggested. ⋯ During the scanning procedure, in which participants were confronted with highly negative emotional pictures, the significant increase in sAA levels in the PL group compared to the BB group persisted. No additional change was noticed in heart rate or blood pressure during scanning in the PL or BB group. The current pharmacological study in the human provides direct evidence for the sensitivity of sAA to changes in adrenergic activation, specifically in reaction to psychological stress.
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Psychoneuroendocrinology · Jan 2006
Clinical TrialStress-induced changes in human salivary alpha-amylase activity -- associations with adrenergic activity.
The salivary enzyme alpha-amylase has been proposed to indicate stress-reactive bodily changes. A previous study by the authors revealed marked increases in salivary alpha-amylase following psychosocial stress, indicating a stress-dependent activation of salivary alpha-amylase. Salivary alpha-amylase has been suggested to reflect catecholaminergic reactivity. ⋯ Analysis of cardiovascular parameters indicates a positive relationship between amylase and sympathetic tone (LF/HF) during stress. Salivary alpha-amylase is sensitive to psychosocial stress. Since it does not seem to be closely related to other biological stress markers such as catecholamines and cortisol, salivary alpha-amylase may be a useful additional parameter for the measurement of stress.
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Psychoneuroendocrinology · Jan 2006
Comparative StudySex and ovarian steroids modulate brain-derived neurotrophic factor (BDNF) protein levels in rat hippocampus under stressful and non-stressful conditions.
Abnormal levels of brain-derived neurotrophic factor (BDNF) are associated with major depression, a disorder with a higher incidence in women than men. Stress affects BDNF levels in various brain regions and thus, a heightened stress response in females could contribute to the development of depression. As well, ovarian hormones directly affect brain levels of BDNF mRNA and protein. ⋯ Thus, stress increased BDNF levels in EP-treated rats but decreased BDNF levels in vehicle-treated rats. Reduced trophic support in DG in the presence of estrogen and progesterone could jeopardize neurogenesis and under certain conditions could be a contributing factor to the hippocampal atrophy associated with stress-induced affective disorders. These results emphasize the need to consider sex, gonadal steroids, and hippocampal subregion when examining the effects of stress on the brain.