Stress hormone-related psychopathology: pathophysiological and treatment implications

Depression gets old fast: do stress and depression accelerate cell aging?

Depression has been likened to a state of "accelerated aging," and depressed individuals have a higher incidence of various diseases of aging, such as cardiovascular and cerebrovascular diseases, metabolic syndrome, and dementia. Chronic exposure to certain interlinked biochemical pathways that mediate stress-related depression may contribute to "accelerated aging," cell damage, and certain comorbid medical illnesses. Biochemical mediators explored in this theoretical review include the hypothalamic-pituitary-adrenal axis (e.g., hyper- or hypoactivation of glucocorticoid receptors), neurosteroids, such as dehydroepiandrosterone and allopregnanolone, brain-derived neurotrophic factor, excitotoxicity, oxidative and inflammatory stress, and disturbances of the telomere/telomerase maintenance system. A better appreciation of the role of these mediators in depressive illness could lead to refined models of depression, to a re-conceptualization of depression as a whole body disease rather than just a "mental illness," and to the rational development of new classes of medications to treat depression and its related medical comorbidities.

Single-dose and chronic corticosterone treatment alters c-Fos or FosB immunoreactivity in the rat cerebral cortex

The aim of this study was to examine the effects of single-dose and chronic corticosterone treatment on the inducible transcription factor c-Fos and FosB, and thereby to estimate the effects of high-doses of corticosterone on calcium-dependent neuronal responses in the rat cerebral cortex. At the same time we investigated the distribution of interneurons containing calretinin (CR), vasoactive intestinal polypeptide (VIP) and neuropeptide Y (NPY) in chronically treated animals in order to collect data on the involvement of inhibitory neurons in this process. Adult male rats were injected subcutaneously with 10mg corticosterone, whereas controls received the vehicle (sesame oil). The animals were fixed by transcardial perfusion 12 and 24h following single corticosterone injection, and the brains were processed for c-Fos and FosB immunohistochemistry. To investigate the effects of repeated corticosterone administration, rats were daily treated with the same amount of corticosterone (10mg/animal, subcutaneously) for 21 days. Controls were injected with vehicle. At the end of the experiment, the rats were perfused and immunohistochemistry was used to detect the presence of the FosB protein, CR, VIP and NPY. Quantitative evaluation of immunolabelled cells was performed in the neocortex and the hippocampus. The number of immunoreactive nuclei per unit area was used as a quantitative measure of the effects of corticosterone. It was found that a single-dose administration of corticosterone resulted in a significant, time-dependent increase of c-Fos protein immunoreactivity in the granule cell layer of the dentate gyrus, as well as in regions CA1 and CA3 of the hippocampus 12 and 24h post-injection with respect to control animals. Significant enhancement of c-Fos immunoreactivity was also observed in the neocortex at 12 and 24h post-injection. Single-dose treatment did not significantly alter FosB immunolabelling. Repeated administration of corticosterone produced a complex pattern of changes in FosB immunolabelling: significant increase in FosB immunoreactivity was detected in the granule cell layer of the dentate gyrus, with no significant changes in the CA1 and CA3 layers of the hippocampus and in the neocortex. However, a significant decrease of FosB induction in the neocortex was observed in chronically treated rats in comparison to single-dose injected animals (12h before immunohistochemistry). Analysis of immunohistochemical detection of interneuronal markers revealed a significant reduction of the CR immunolabelling in the CA3 area of the hippocampus. No changes in VIP or NPY immunoreactivity were found in the Ammon's horn 3 weeks following daily corticosterone treatment. NPY immunoreactivity was significantly attenuated in the neocortex. The present data suggest that single-dose corticosterone treatment increases immunoreactivity of c-Fos protein in a time-dependent manner, 12 and 24h post-injection in the rat hippocampus and the neocortex, whereas chronic corticosterone treatment influences FosB immunoreactivity, primarily in the dentate gyrus. Chronic corticosterone administration seems to affect CR levels in the CA3 area of the hippocampus.

Protocol for an experimental investigation of the roles of oxytocin and social support in neuroendocrine, cardiovascular, and subjective responses to stress across age and gender

Background

Substantial empirical evidence has demonstrated that individuals who are socially isolated or have few positive social connections seem to age at a faster rate and have more chronic diseases. Oxytocin is a neurohypophyseal hormone hypothesized to coordinate both the causes and effects of positive social interactions, and may be involved in positive physiological adaptations such as buffering the deleterious effects of stress and promoting resilience. The proposed research will examine whether and how oxytocin influences responses to stress in humans and will consider effects in relation to those of social support.

Methods/Design

Experimental research will be used to determine whether exogenously administered oxytocin (intranasal) influences psychological and physiological outcomes under conditions of stress across gender and age in adulthood. Hypotheses to be tested are: 1) Oxytocin ameliorates the deleterious neuroendocrine, cardiovascular, and subjective effects of stress; 2) Oxytocin and social support have similar and additive stress-buffering effects; 3) Oxytocin effects are stronger in women versus men; and 4) Oxytocin effects are similar across a range of adult ages. Hypotheses will be tested with a placebo-controlled, double-blind study using a sample of healthy men and women recruited from the community. Participants are randomly assigned to receive either oxytocin or placebo. They undergo a social stress manipulation with and without social support (randomly assigned), and outcome measures are obtained at multiple times during the procedure.

Discussion

Understanding the determinants of healthy aging is a major public health priority and identifying effective measures to prevent or delay the onset of chronic diseases is an important goal. Experimental research on oxytocin, social relationships, and health in adulthood will contribute to the scientific knowledge base for maximizing active life and health expectancy. At conclusion of the study we will have solid evidence concerning the effects of oxytocin on stress response and whether it has similar effects across age and gender groups. A neurobiological understanding of resilience can inform efforts for both prevention and intervention of diseases or problems common in later life.

Trial registration

Clinical trial identification number is NCT01011465.

Neurobiological Pathways between Chronic Stress and Depression: Dysregulated Adaptive Mechanisms?

Stress-related diseases have been predicted to become major contributors to the Global Disease Burden within the next 20 years. Of these, depression is one of the principal identifiable sources of concern for public mental health, and has been hypothesized to be an outcome of prolonged stress. Examination of the hyper-responsiveness of the Hypothalamic-Pituitary-Adrenal axis, consequent elevated serum cortisol, plus the effects of this upon brain structure and function, provides a model for understanding how chronic stress may be a causal vector in the development of depression. Evidence from studies of the effectiveness of antidepressants aimed at reducing cortisol within depressed patients supports this model and suggests avenues for future research and treatment of stress-induced depression.

Glucocorticoids. Mood, memory, and mechanisms

Elevated circulating levels of glucocorticoids are associated with psychiatric symptoms across several different conditions. It remains unknown if this hormonal abnormality is a cause or an effect of the psychiatric conditions. For example, the hypercortisolemia observed in a subset of patients with depression may have a direct impact on the symptoms of depression, but it is also possible that the hypercortisolemia merely reflects the stress associated with depression. Further, rather than causing depression, hypercortisolemia could represent a homeostatic attempt to overcome glucocorticoid resistance. Each of these possibilities will be considered, and correlational and causal evidence will be reviewed. This article will focus on the relationships between glucocorticoids and psychiatric symptoms in Cushing's syndrome, major depression, and steroid psychosis/steroid dementia, as well as the effects of exogenously administered glucocorticoids in normal volunteers. Similarities and differences in the relationship of glucocorticoid hormones to psychiatric symptoms in these conditions will be reviewed. Possible mediators of glucocorticoid effects on the brain and behavior, as well as possible "pro-aging" effects of glucocorticoids in certain cells of the body, will be reviewed. The article concludes with a conceptual model of glucocorticoid actions in the brain that may lead to novel therapeutic opportunities.

Can meditation slow rate of cellular aging? Cognitive stress, mindfulness, and telomeres

Understanding the malleable determinants of cellular aging is critical to understanding human longevity. Telomeres may provide a pathway for exploring this question. Telomeres are the protective caps at the ends of chromosomes. The length of telomeres offers insight into mitotic cell and possibly organismal longevity. Telomere length has now been linked to chronic stress exposure and depression. This raises the question of mechanism: How might cellular aging be modulated by psychological functioning? We consider two psychological processes or states that are in opposition to one another-threat cognition and mindfulness-and their effects on cellular aging. Psychological stress cognitions, particularly appraisals of threat and ruminative thoughts, can lead to prolonged states of reactivity. In contrast, mindfulness meditation techniques appear to shift cognitive appraisals from threat to challenge, decrease ruminative thought, and reduce stress arousal. Mindfulness may also directly increase positive arousal states. We review data linking telomere length to cognitive stress and stress arousal and present new data linking cognitive appraisal to telomere length. Given the pattern of associations revealed so far, we propose that some forms of meditation may have salutary effects on telomere length by reducing cognitive stress and stress arousal and increasing positive states of mind and hormonal factors that may promote telomere maintenance. Aspects of this model are currently being tested in ongoing trials of mindfulness meditation.

Neurobiological and neuropsychiatric effects of dehydroepiandrosterone (DHEA) and DHEA sulfate (DHEAS)

DHEA and DHEAS are steroids synthesized in human adrenals, but their function is unclear. In addition to adrenal synthesis, evidence also indicates that DHEA and DHEAS are synthesized in the brain, further suggesting a role of these hormones in brain function and development. Despite intensifying research into the biology of DHEA and DHEAS, many questions concerning their mechanisms of action and their potential involvement in neuropsychiatric illnesses remain unanswered. We review and distill the preclinical and clinical data on DHEA and DHEAS, focusing on (i) biological actions and putative mechanisms of action, (ii) differences in endogenous circulating concentrations in normal subjects and patients with neuropsychiatric diseases, and (iii) the therapeutic potential of DHEA in treating these conditions. Biological actions of DHEA and DHEAS include neuroprotection, neurite growth, and antagonistic effects on oxidants and glucocorticoids. Accumulating data suggest abnormal DHEA and/or DHEAS concentrations in several neuropsychiatric conditions. The evidence that DHEA and DHEAS may be fruitful targets for pharmacotherapy in some conditions is reviewed.

Neurosteroid dehydroepiandrosterone exerts anti-apoptotic effects by membrane-mediated, integrated genomic and non-genomic pro-survival signaling pathways

Dehydroepiandrosterone (DHEA) protects neural crest-derived PC12 cells from serum deprivation-induced apoptosis via G protein-associated specific plasma membrane-binding sites (mDBS). Here, we studied the signaling pathways involved in the pro-survival effects of DHEA-mediated activation of the mDBS binding sites. Membrane impermeable DHEA-bovine serum albumin (BSA) conjugate induced an acute phosphorylation of the prosurvival kinases Src, protein kinase A (PKA), MEK1/2/ERK1/2, and PI3K/Akt in serum deprived PC12 cells in parallel to an elevation of intracellular cAMP. The physiological significance of these findings was further assessed in a series of experiments using several selective pro-survival kinase inhibitors. Our combined findings suggest that the following sequence of events may take place following activation of mDBS binding sites: DHEA-BSA induces an acute but transient sequential phosphorylation of the pro-survival kinases Src/PKC(a/b)/MEK1/2/ERK1/2 which, in their turn, activate transcription factors cAMP responsive element binding protein and nuclear factor kappa B which induce the expression of the anti-apoptotic Bcl-2 genes. In parallel, DHEA-BSA increases intracellular cAMP, and the subsequent phosphorylation of PKA kinase and of cAMP responsive element binding protein. Finally, DHEA-BSA induces phosphorylation of PI3K/Akt kinases which, subsequently, lead to phosphorylation/deactivation of the pro-apoptotic Bad. Our findings suggest that the neurosteroid DHEA affects neural crest-derived cell survival by multiple pro-survival signaling pathways comprising an integrated system of non-genomic and genomic mechanisms.

Why egalitarianism might be good for your health: physiological thriving during stressful intergroup encounters

We compared how evaluations by out-group members and evaluations by in-group members affected participants' stress responses--their neuroendocrine reactivity, cognitive appraisals, and observed anxiety--and how participants' implicit racial bias moderated these responses. Specifically, White participants completed measures of racial bias prior to the experiment. During the experiment, participants performed speech and serial subtraction tasks in front of White or Black interviewers. Several saliva samples were obtained, and they were assayed for catabolic ("breaking down") and anabolic ("building up") hormones. Interviewers' race and participants' racial bias interacted in predicting stress responses. When interviewers were Black, lower racial bias was linked with more salutary stress responses: lower threat appraisals, less anxiety, and increased levels of anabolic hormones. When interviewers were White, no effect was found for threat appraisals or anabolic hormones, and the reverse effect was observed for anxiety. Egalitarianism may have physical and psychological benefits for people living in a diverse society.

The "steroid dementia syndrome": a possible model of human glucocorticoid neurotoxicity

Glucocorticoid medications cause neurotoxicity in animals under certain circumstances, but it is not known if this occurs in humans. We present the case of a 10-year-old boy with no prior psychiatric history and no prior exposure to glucocorticoid medication who received a single 5-week course of glucocorticoids for an acute asthma flare. Beginning during steroid treatment, and persisting for over 3 years after stopping treatment, he showed a significant decline from his pre-morbid academic performance and estimated IQ, verified by longitudinally administered testing and school records. Neuropsychological tests that are sensitive to glucocorticoid-induced cognitive impairments revealed global cognitive deficits consistent with primary hippocampal and prefrontal cortical dysfunction. The patient has a fraternal twin brother, who had previously achieved academic milestones in parallel with him; the patient began falling behind his twin in academic, developmental and social areas shortly after the steroid treatment. In the 3 years since stopping steroid medication, the patient has shown gradual but possibly incomplete resolution of his cognitive deficits. Quantitative brain magnetic resonance imaging (MRI), performed 38 months after steroid exposure revealed no gross abnormalities, but the patient's hippocampal volume was 19.5% smaller than that of his twin, despite the patient having a larger overall intracranial volume. Single photon emission computed tomography (SPECT) imaging, performed at the same time, suggested subtly decreased activity in the left posterior frontal and left parietal lobes. This case, along with others reported in the literature, suggests that certain individuals develop a "steroid dementia syndrome" after glucocorticoid treatment. Although this syndrome is uncommon, it is consistent with evolving theories of the neurotoxic or neuroendangering potential of glucocorticoids in some situations.

Neurosteroids as endogenous inhibitors of neuronal cell apoptosis in aging

The neuroactive steroids dehydroepiandrosterone (DHEA), its sulfate ester DHEAS, and allopregnanolone (Allo) are produced in the adrenals and the brain. Their production rate and levels in serum, brain, and adrenals decrease gradually with advancing age. The decline of their levels was associated with age-related neuronal dysfunction and degeneration, most probably because these steroids protect central nervous system (CNS) neurons against noxious agents. Indeed, DHEA(S) protects rat hippocampal neurons against NMDA-induced excitotoxicity, whereas Allo ameliorates NMDA-induced excitotoxicity in human neurons. These steroids exert also a protective role on the sympathetic nervous system. Indeed, DHEA, DHEAS, and Allo protect chromaffin cells and the sympathoadrenal PC12 cells (an established model for the study of neuronal cell apoptosis and survival) against serum deprivation-induced apoptosis. Their effects are time- and dose-dependent with EC(50) 1.8, 1.1, and 1.5 nM, respectively. The prosurvival effect of DHEA(S) appears to be NMDA-, GABA(A)- sigma1-, or estrogen receptor-independent, and is mediated by G-protein-coupled-specific membrane binding sites. It involves the antiapoptotic Bcl-2 proteins, and the activation of prosurvival transcription factors CREB and NF-kappaB, upstream effectors of the antiapoptotic Bcl-2 protein expression, as well as prosurvival kinase PKCalpha/beta, a posttranslational activator of Bcl-2. Furthermore, they directly stimulate biosynthesis and release of neuroprotective catecholamines, exerting a direct transcriptional effect on tyrosine hydroxylase, and regulating actin depolymerization and submembrane actin filament disassembly, a fast-response cellular system regulating trafficking of catecholamine vesicles. These findings suggest that neurosteroids may act as endogenous neuroprotective factors. The decline of neurosteroid levels during aging may leave the brain unprotected against neurotoxic challenges.

Therapy Insight: is there an imbalanced response of mineralocorticoid and glucocorticoid receptors in depression?

In severely depressed patients, emotional arousal, cognitive abnormality and vulnerability to psychotic episodes are linked to a hyperactive hypothalamic-pituitary-adrenal (HPA) axis and high levels of circulating cortisol. The susceptibility pathways underlying these disturbed brain functions are influenced by genetic factors, early-life priming experiences and later-life events. Cortisol is an important determinant in this so-called three hit model. The action of cortisol is protective, but can become harmful if exposure of susceptibility pathways to the stress hormone is excessive and sustained or inadequate. In this article we argue that this change in role of cortisol from protective into harmful depends on the functioning of the mineralocorticoid and glucocorticoid receptors and the context in which the organism experiences the stressor. Actions mediated by the mineralocorticoid and glucocorticoid receptors are complementary and operate in different time domains of the stress response: the mineralocorticoid receptor normally prevents stress-induced disturbances, but if such disturbances occur the glucocorticoid receptor helps the recovery process. An imbalance in these receptor-mediated actions is thought to increase vulnerability to stress-related psychiatric disorders in predisposed individuals. Correction of the imbalance between the mineralocorticoid receptor and the glucocorticoid receptor can, therefore, facilitate recovery processes still present in the diseased brain, provided that the right psychological context is offered to the individual.

Targeting 11β-hydroxysteroid dehydrogenase type 1 in brain: therapy for cognitive aging?

Dementia care costs exceed those of cardiovascular diseases and cancer combined. Milder forms of functionally significant cognitive decline add further to the staggering human, societal and economic costs. However, the underlying mechanisms are poorly understood and few treatments are available. Cumulative exposure to high glucocorticoid levels is a major hypothesis of decline in cognitive function with aging. Current manipulations to maintain low circulating glucocorticoid levels throughout life (adrenalectomy with low-dose corticosterone replacement and neonatal handling), although effective in preventing the emergence of memory deficits with age in rodent models, are not clinically applicable. By contrast, recent data in cells, mice and humans suggest that inhibition of the tissue-selective glucocorticoid-amplifying enzyme, 11β-hydroxysteroid dehydrogenase type 1, may be an effective novel approach.

Subjective effects and changes in steroid hormone concentrations in humans following acute consumption of alcohol

BACKGROUND

GABAA receptors are an important site of action of endogenous neurosteroids and an important mediator of several behavioral effects of alcohol. This study examined the effects of alcohol on plasma steroid hormone concentrations on the hypothesis that the endocrine effects mediate some of the subjective effects of alcohol.

METHODS

Thirty-two healthy subjects (17 men) with no history of a substance use disorder participated in this human laboratory study. All subjects consumed three standard drinks of grain alcohol. Subjective measures and blood samples for steroid concentrations were collected at baseline and 40 min after alcohol consumption.

RESULTS

Alcohol increased self-reported stimulation, alcohol liking, and desire for more alcohol. Alcohol also increased pregnenolone (PREG) and dehydroepiandrosterone (DHEA) concentrations, while it decreased progesterone (PROG) and allopregnanolone (ALLO) concentrations, as well as ALLO/PREG and PROG/PREG ratios. In men, the change in PREG concentration was significantly correlated with alcohol liking, while the alcohol-induced change in ALLO concentration correlated significantly with both alcohol liking and desire for more alcohol.

DISCUSSION

These findings provide preliminary support for the hypothesis that endogenous neurosteroids mediate some of the subjective effects of alcohol. Efforts to replicate these findings should aim to specify more clearly the nature and time course of the effects.

Neuroactive steroids, negative affect, and nicotine dependence severity in male smokers

RATIONALE

Nicotine administration alters neuroactive steroids in rodent models, and serum levels of the neuroactive steroid DHEAS (dehydroepiandrosterone sulfate) appear to be higher in smokers. These molecules may be relevant to tobacco addiction and affective symptoms.

OBJECTIVES

This study aims to investigate DHEAS, allopregnanolone, pregnenolone, and other steroids in male smokers to determine potential associations with nicotine dependence severity and negative affect.

MATERIALS AND METHODS

Allopregnanolone and pregnenolone serum levels were determined by gas chromatography/mass spectrometry, while DHEAS and other steroid levels were determined by radioimmunoassay in 28 male smokers. Correlational analyses were performed to determine potential associations with rating measures, including the Fagerstrom Test for Nicotine Dependence (FTND), the addiction subscale of the Ikard Smoking Motivation Questionnaire (ISMQ), the craving item on the Reasons to Smoke (RTS) Questionnaire, and the negative affect and craving subscales of the Shiffman-Jarvik Withdrawal Questionnaire.

RESULTS

DHEAS levels were inversely correlated with the negative affect subscale of the Shiffman-Jarvik Withdrawal Questionnaire (r=-0.60, p=0.002) and the RTS craving item (r=-0.43, p=0.03), and tended to be inversely correlated with the FTND scores (r=-0.38, p=0.067) and the ISMQ addiction subscale (r=-0.38, p=0.059), adjusting for age. Allopregnanolone levels were positively correlated with cotinine levels (r=0.57, p=0.006); pregnenolone levels tended to be positively correlated with cotinine levels (r=0.40, p=0.066).

CONCLUSIONS

DHEAS levels were inversely correlated with negative affect and craving measures, and may predict nicotine dependence severity. Allopregnanolone levels were positively correlated with cotinine levels, suggesting that this neuroactive steroid may be upregulated in smokers. Neuroactive steroids may represent novel smoking cessation agents.

Neuroactive steroids are altered in schizophrenia and bipolar disorder: relevance to pathophysiology and therapeutics

Evidence suggests that neuroactive steroids may be candidate modulators of schizophrenia pathophysiology and therapeutics. We therefore investigated neuroactive steroid levels in post-mortem brain tissue from subjects with schizophrenia, bipolar disorder, nonpsychotic depression, and control subjects to determine if neuroactive steroids are altered in these disorders. Posterior cingulate and parietal cortex tissue from the Stanley Foundation Neuropathology Consortium collection was analyzed for neuroactive steroids by negative ion chemical ionization gas chromatography/mass spectrometry preceded by high-performance liquid chromatography. Subjects with schizophrenia, bipolar disorder, nonpsychotic depression, and control subjects were group matched for age, sex, ethnicity, brain pH, and post-mortem interval (n = 14-15 per group, 59-60 subjects total). Statistical analyses were performed by ANOVA with post-hoc Dunnett tests on log transformed neuroactive steroid levels. Pregnenolone and allopregnanolone were present in human post-mortem brain tissue at considerably higher concentrations than typically observed in serum or plasma. Pregnenolone and dehydroepiandrosterone levels were higher in subjects with schizophrenia and bipolar disorder compared to control subjects in both posterior cingulate and parietal cortex. Allopregnanolone levels tended to be decreased in parietal cortex in subjects with schizophrenia compared to control subjects. Neuroactive steroids are present in human post-mortem brain tissue at physiologically relevant concentrations and altered in subjects with schizophrenia and bipolar disorder. A number of neuroactive steroids act at inhibitory GABA(A) and excitatory NMDA receptors and demonstrate neuroprotective and neurotrophic effects. Neuroactive steroids may therefore be candidate modulators of the pathophysiology of schizophrenia and bipolar disorder, and relevant to the treatment of these disorders.

The relevance of neurosteroids to clinical psychiatry: from the laboratory to the bedside

Neurosteroids are important neuroactive molecules with suggested central involvement in several neurophysiological and psychiatric disease processes. The discovery of neurosteroids followed the revelation that the brain exhibited the capacity to synthesize its own steroids in situ and thus be a potential site of steroidogenesis. In contrast to some steroids that exhibit traditional genomic steroid actions, most neurosteroids appear to regulate neuronal function by means of "non-genomic" mechanisms influencing neuronal excitability. Neurosteroids are synthesized either from CNS cholesterol or from peripheral steroid precursors and exhibit a wide range of modulatory effects on neurotransmitter receptor activity, most notably at the gamma-aminobutyric acid A (GABA(A)) receptor. Neurosteroids play an important role in neurodevelopment and neuroprotective effects, many aspects of which may have particular applicability to psychiatric disorders including various gender differences. Neurosteroids appear to be relevant to the pathophysiology and pharmacological treatment of many psychiatric disorders including the most notable mood and anxiety disorders, but also psychotic, childhood, eating, dementia, stress and postpartum disorders. It has been suggested that neurosteroids may become potential targets for pharmacological intervention in the future with further neurosteroid investigation contributing to a more comprehensive understanding of human behavior and psychopathology.

Differential effects of predator stress and the antidepressant tianeptine on physiological plasticity in the hippocampus and basolateral amygdala

Stress can profoundly affect memory and alter the functioning of the hippocampus and amygdala. Studies have also shown that the antidepressant tianeptine can block the effects of stress on hippocampal and amygdala morphology and synaptic plasticity. We examined the effects of acute predator stress and tianeptine on long-term potentiation (LTP; induced by 100 pulses in 1 s) and primed burst potentiation (PB; a low threshold form of LTP induced by only five physiologically patterned pulses) in CA1 and in the basolateral nucleus (BLA) of the amygdala in anesthetized rats. Predator stress blocked the induction of PB potentiation in CA1 and enhanced LTP in BLA. Tianeptine blocked the stress-induced suppression of PB potentiation in CA1 without affecting the stress-induced enhancement of LTP in BLA. In addition, tianeptine administered under non-stress conditions enhanced PB potentiation in the hippocampus and LTP in the amygdala. These findings support the hypothesis that acute stress impairs hippocampal functioning and enhances amygdaloid functioning. The work also provides insight into the actions of tianeptine with the finding that it enhanced electrophysiological measures of plasticity in the hippocampus and amygdala under stress, as well as non-stress, conditions.

Stress response and binge eating disorder

In clinical practice, obese patients report stress as a primary trigger for binge eating. However, the biological mechanism underlying this relationship is poorly understood. This paper presents, a theoretical overview of how cortisol secretion, a major component of the stress response, could play a role in binge eating, given that exogenous glucocorticoids can lead to obesity by increasing food intake. I will discuss findings from recent studies demonstrating links between laboratory stress, cortisol, food intake and abdominal fat in humans. Cortisol is elevated following laboratory stressors in women with anorexia nervosa (AN), bulimia nervosa (BN), and obesity, but has not been widely studied in women with binge eating disorder (BED). Additionally, I will review recent findings demonstrating a greater cortisol response to stress in obese women with BED compared to non-BED.

Desensitization of 5-HT2A receptor function by chronic administration of selective serotonin reuptake inhibitors

We have previously shown that chronic treatment with selective serotonin reuptake inhibitors (SSRIs), fluvoxamine and paroxetine, attenuated m-chlorophenylpiperazine (mCPP)-induced hypolocomotion in rats. The effect of these SSRIs on the response to mCPP is thought to be caused by the desensitization of 5-HT2C receptor function. In the present study, we investigated whether chronic administration of SSRI could reduce another pharmacological response to mCPP in rats, i.e., the induction of the secretion of corticosterone. The mCPP-induced increase in the serum concentration of corticosterone was not blocked by the 5-HT2C antagonist SB242084, but was blocked by the 5-HT2A antagonist ketanserin. Chronic treatment with fluvoxamine and paroxetine attenuated the response to mCPP, while these SSRIs had no effects in control rats. These results suggest that the desensitization of 5-HT2A receptor function occurs in the same way as that of 5-HT2C receptor function through chronic treatment with either fluvoxamine or paroxetine as a consequence of prolonged exposure to elevated levels of serotonin. The hypersensitivity of 5-HT2A receptors is observed in depressed patients, and chronic treatment with many antidepressants such as tricyclic antidepressants have been reported to reduce 5-HT2A receptor density and/or efficacy. The desensitization of 5-HT2A receptor function might contribute to the therapeutic mechanism of action of these SSRIs, as seen with other classes of antidepressants.

Cortisol level predicts executive and memory function in depression, symptom level predicts psychomotor speed

OBJECTIVE

On a group level depression is related to hypercortisolism and to psychomotor retardation, executive dysfunction and memory impairment. However, intra-group heterogeneity is substantial. Why some are impaired while others remain in the normal range, is not clear. The present study aims at discerning the relative contribution of present symptom severity and hypercortisolism to impairment in the three domains of cognition.

METHOD

Morning saliva cortisol was measured in 26 subjects with recurrent major depression prior to a neuropsychological examination with tests known to be sensitive to cognitive impairment in depression.

RESULTS

Cortisol level correlated with executive dysfunction and post-encoding memory deficits, but not with processing speed. Depression level correlated with processing speed. These patterns remained significant after controlling for confounders through partial correlations.

CONCLUSION

The association between cortisol and cognition is not an artifact of psychiatric symptom load. High level of saliva cortisol is associated with aspects of cognition that can be dissociated from psychomotor retardation, which is dependent on symptom load.

Depressive symptoms and 24-hour urinary norepinephrine excretion levels in patients with coronary disease: findings from the Heart and Soul Study

OBJECTIVE

Depressive symptoms are associated with an increased risk of cardiac events in patients with heart disease. Elevated catecholamine levels may contribute to this association, but whether depressive symptoms are associated with catecholamine levels in patients with heart disease is unknown.

METHOD

The authors examined the association between depressive symptoms (defined by a Patient Health Questionnaire score > or =10) and 24-hour urinary norepinephrine, epinephrine, and dopamine excretion levels in 598 subjects with coronary disease.

RESULTS

A total of 106 participants (18%) had depressive symptoms. Participants with depressive symptoms had greater mean norepinephrine excretion levels than those without depressive symptoms (65 microg/day versus 59 mug/day, with adjustment for age, sex, body mass index, smoking, urinary creatinine levels, comorbid illnesses, medication use, and cardiac function). In logistic regression analyses, participants with depressive symptoms were more likely than those without depressive symptoms to have norepinephrine excretion levels in the highest quartile and above the normal range. Depressive symptoms were not associated with dopamine or epinephrine excretion levels.

CONCLUSIONS

In patients with coronary disease, depressive symptoms are associated with elevated norepinephrine excretion levels. Future longitudinal studies are needed to determine whether elevations in norepinephrine contribute to adverse cardiac outcomes in patients with depressive symptoms.

Stress responses at birth: determinants of cord arterial cortisol and links with cortisol response in infancy

OBJECTIVE

To investigate (A) the determinants of infant stress response at delivery and (B) test the hypothesis that stress at birth, as reflected by cord arterial cortisol, influences cortisol response to vaccination at two months.

DESIGN

Prospective observational study.

SETTING

Tertiary referral maternity hospital.

POPULATION

One hundred and seventy-two primiparous women with uncomplicated singleton pregnancies.

METHODS

Women were recruited antenatally. At birth, cord arterial blood and obstetric data were collected. Saliva was collected from infants immediately before and after vaccination at two months. Cortisol was analysed from cord blood and saliva by radio-immunoassay.

MAIN OUTCOME MEASURES

Stress response at birth, as demonstrated by cord arterial cortisol; association with saliva cortisol response to vaccination at two months.

RESULTS

Cord arterial cortisol varied with mode of delivery, combined spinal/epidural use and pH. Salivary cortisol response at two months correlated with cord arterial cortisol (r= 0.24, P < 0.05). Infants with the highest and lowest cord arterial cortisol had markedly different cortisol responses at two months (P= 0.017). These groups had different modes of delivery with caesarean rates of <8% in the high cortisol response group and 83% in the low cortisol response group (P < 0.0001).

CONCLUSION

Babies born vaginally mount greater cortisol responses at birth than those delivered by caesarean section. Stress at delivery may influence the infant HPA axis response for up to two months.

Hypothalamic-pituitary-adrenal axis activity and sleep in posttraumatic stress disorder

Alterations of the hypothalamic-pituitary-adrenal (HPA) axis and sleep disturbances have been described separately in post-traumatic stress disorder (PTSD). It is not known if HPA alterations and sleep disturbances are associated in PTSD. This study examined sleep and HPA activity in 20 male medication-free subjects with PTSD and 16 matched healthy controls. Two nights of polysomnography were obtained and 24-h urinary cortisol was collected during day 2. Subjects self-administered a low-dose (0.5 mg) salivary dexamethasone test at home. Compared with controls, PTSD subjects had higher 24-h urinary microg cortisol/g creatinine (mean+/-SD 40+/-17 vs 28+/-12, p=0.03) but not significantly higher 24-h urinary cortisol (mean+/-SD 52+/-15 microg/day vs 43+/-23, p=0.19). PTSD subjects showed a trend towards less cortisol suppression after dexamethasone (73%+/-18 vs 83%+/-10, p=0.06). In the combined sample, delta sleep was significantly and negatively correlated with 24-h urinary cortisol (r=-0.36, p=0.04), and with 24-h urinary cortisol/g creatinine on a trend level (r=-0.34, p=0.06). Our results suggest that increased cortisol is negatively associated with delta sleep. This may contribute to sleep abnormalities in conditions associated with elevated cortisol, possibly including PTSD. Future studies should explore the temporal relationship between HPA activity, sleep disturbances, and psychopathology after a traumatic event.

Pubertal neuromaturation, stress sensitivity, and psychopathology

Normal adolescent development is often accompanied by transient emotional and behavioral problems. For most individuals with postpubertal-onset adjustment problems, there is a resolution by early adulthood and relative stability through the adult life span. But for a minority, adjustment problems escalate during adolescence and portend the development of serious mental illness in adulthood. In this article, we explore adolescent behavioral changes and neurodevelopmental processes that might contribute to stress sensitivity and vulnerability for the emergence of the mental disorders. Of particular interest is the role that hormonal changes might play in the expression of genetic vulnerabilities for psychopathology. Drawing on recent findings from clinical research and behavioral neuroscience, we describe the ways in which postpubertal hormones might alter brain function and, thereby, behavior. It is concluded that there are both activational and organization effects of hormones on the adolescent brain, and these contribute to developmental discontinuities in behavioral adjustment. Implications for adult psychopathology and preventive intervention are discussed.

Stress model for research into preterm delivery among black women

The disparity between black and white infant mortality rates increased over the last decade, despite overall improvement in infant survival. Because most black infant deaths are related to preterm delivery, the discovery of the cause of premature birth in general and excess premature birth for black infants in particular is of paramount importance for reproductive health research. Substantial theoretic support exists for maternal stress as a risk factor for preterm birth. Traumatic events early in life may sensitize the adult to contemporary stresses and increase her vulnerability to stress-induced neuroendocrine or infection/inflammatory pathways to early parturition. In addition, an individual may prematurely age as a result of cumulative stress or a major traumatic event. This "stress age," which is synonymous with the concept of weathering and similar to the concept of allostatic load, may affect parturition through chronic conditions (such as hypertension) and in poorly understood pathophysiologic mechanisms that are related to increased chronologic age. One potential measure of stress age is maternal serum dehydroepiandrosterone sulfate. Maternal stress is a potential explanatory factor for excess preterm delivery among black women because of their exposure to racism-associated stress. However, few studies have addressed this question, and results are mixed. Future etiologic research must take into account the complexities of the measurement of stress age and past and current exposures to stress, which includes internalized racism and interpersonal racism.

Child maltreatment and HPA axis dysregulation: relationship to major depressive disorder and post traumatic stress disorder in females

A history of child maltreatment increases the vulnerability to the development of Major Depressive Disorder (MDD) and/or Posttraumatic Stress Disorder (PTSD), especially in females. Both MDD and PTSD are associated with a dysregulation of the Hypothalamic-Pituitary-Adrenal (HPA) axis. Dysregulation of the HPA axis may be an important etiological link between child maltreatment and subsequent psychiatric disorder, yet little is known about the relationship between exposure and outcome. The aim of this review is to explore the role of HPA axis dysregulation in the link between child maltreatment and MDD/PTSD among women. Studies of females with MDD frequently indicate a hyperactivity of the HPA axis, and contribute to our understanding of the underlying mechanisms involved in mood dysregulation. Evidence for HPA axis dysregulation in PTSD is less convincing and suggests that timing of the stressful experience as well as the type of the trauma may influence the outcome. The strongest evidence to date suggesting that the development of the HPA axis may be affected by early life stressful experiences comes from pre-clinical animal studies. Together these studies add to our understanding of the role of the HPA axis in psychiatric disorders in relation to stress. The literature on HPA axis function in both children and adults following child maltreatment further highlights the potential relevance of early stress to later onset of major psychiatric disorders. Such knowledge may also contribute to the development of early interventions targeted at primary prevention.

A meta-analysis of cortisol response to challenge in human aging: importance of gender

An increased cortisol response to challenge is associated with a variety of age-related disorders such as Alzheimer's disease, depression, diabetes, metabolic syndrome, and hypertension. Among the healthy elderly, an increased cortisol response to challenge may be a risk factor for developing these age-related disorders. We searched Pubmed, Embase, PsychInfo, Biosis, and Digital Dissertations (January 1966-June 2003) and included 45 parallel-group (young vs. old subjects) studies that used either a pharmacological or psychological challenge in healthy volunteers and measured cortisol response to challenge. We calculated effect sizes (Cohen's d) for the standardized mean differences between groups. Compared to younger controls (n=670, mean age 28 years +/-5), older subjects (n=625, 69+/-6) showed a larger cortisol response to challenge defined as stronger response to stimulation or less inhibition after a suppression test (d=0.42, 95% confidence interval (CI), 0.26-0.57). The effect of age on cortisol release was significantly stronger in women (d=0.65, 95% CI 0.34-0.97) than men (d=0.24, 95% CI 0.02-0.47). Our results demonstrate that aging increases the cortisol response to challenge. This effect of age on cortisol response is almost three-fold stronger in women than men. Prospective studies should explore whether the higher cortisol response in the elderly is a risk factor for developing neuropsychiatric and medical disorders.

Effects of Hatha yoga and African dance on perceived stress, affect, and salivary cortisol

BACKGROUND

Dance and yoga have been shown to produce improvements in psychological well-being.

PURPOSE

The aim of this study was to examine some of the psychological and neuroendocrine response to these activities.

METHODS

Sixty-nine healthy college students participated in one of three 90-min classes: African dance (n = 21), Hatha yoga (n= 18), or a biology lecture as a control session (n = 30). Before and after each condition participants completed the Perceived Stress Scale (PSS), completed the Positive Affect and Negative Affect Schedule, and provided a saliva sample for cortisol.

RESULTS

There were significant reductions in PSS and negative affect (ps < .0001) and Time x Treatment interactions (ps < .0001) such that African dance and Hatha yoga showed significant declines, whereas there was no significant change in biology lecture. There was no significant main effect for positive affect (p = .53), however there was a significant interaction effect (p < .001) such that positive affect increased in African dance, decreased in biology lecture, and did not change significantly in Hatha yoga. There was a significant main effect for salivary cortisol (p < .05) and a significant interaction effect (p < .0001) such that cortisol increased in African dance, decreased in Hatha yoga, and did not change in biology. Changes in cortisol were not significantly related to changes in psychological variables across treatments. There was 1 significant interaction effect (p = .04) such that change in positive affect and change in cortisol were negatively correlated in Hatha yoga but positively correlated in Africa dance and biology.

CONCLUSIONS

Both African dance and Hatha yoga reduced perceived stress and negative affect. Cortisol increased in African dance and decreased in Hatha yoga. Therefore, even when these interventions produce similar positive psychological effects, the effects may be very different on physiological stress processes. One factor that may have particular salience is that amount of physiological arousal produced by the intervention.

Endocannabinoid signaling negatively modulates stress-induced activation of the hypothalamic-pituitary-adrenal axis

Activation of the hypothalamic-pituitary-adrenal (HPA) axis is critical for the adaptation and survival of animals upon exposure to stressful stimuli, and data suggest that endocannabinoid (eCB) signaling modulates neuroendocrine function. We have explored the role of eCB signaling in the modulation of stress-induced HPA axis activation. Administration of the CB1 receptor antagonist/inverse agonist SR141716 (0.01, 0.1, 1, and 5 mg/kg, i.p.) to male mice produced a small, dose-dependent increase in the serum corticosterone (CORT) concentration. Despite this effect, the highest dose of SR141716 did not significantly increase neuronal activity within the paraventricular nucleus of the hypothalamus, as measured by the induction of Fos protein. Similarly, exposure of mice to 30 min of restraint increased serum CORT concentrations, but did not produce a consistent, statistically significant increase in Fos expression within the PVN. However, pretreatment of mice with SR141716 before restraint stress robustly potentiated restraint-induced CORT release and Fos expression within the PVN. Pretreatment of mice with either the CB1 receptor agonist CP55940, the eCB transport inhibitor AM404, or the fatty acid amide hydrolase inhibitor URB597 significantly decreased or eliminated restraint-induced CORT release. Upon exposure to acute restraint, hypothalamic 2-arachidonylglycerol content was reduced compared with the control value; however, after 5 d of restraint exposure (which resulted in an attenuated CORT response), the hypothalamic 2-arachidonylglycerol content was increased compared with the control value. These data indicate that eCB signaling negatively modulates HPA axis function in a context-dependent manner and suggest that pharmacological augmentation of eCB signaling could serve as a novel approach to the treatment of anxiety-related disorders.

Depression and 24-hour urinary cortisol in medical outpatients with coronary heart disease: The Heart and Soul Study

BACKGROUND

In patients with coronary heart disease (CHD), depression leads to worse cardiovascular outcomes. Depression has been associated with increased cortisol in medically healthy patients, suggesting that cortisol may act as a mediator in the pathway between depression and cardiovascular events. However, it is not known whether depression is associated with elevated cortisol levels in patients with CHD.

METHODS

We examined the association between depression (assessed by the Computerized Diagnostic Interview Schedule) and 24-hour urinary cortisol in 693 medical outpatients with known CHD.

RESULTS

Of 693 participants, 138 (20%) had current depression. Depressed participants had greater mean cortisol levels than those without depression (42 +/- 25 vs. 36 +/- 20 microg/day, p <.01). With each increasing quartile of cortisol concentration the frequency of depression increased (p <.01). Participants in the highest quartile of cortisol had a twofold increased odds of having depression, compared with those in the lowest quartile (odds ratio [OR] 2.1, 95% confidence interval [CR] 1.2-3.6, p =.01). This association remained strong after adjusting for potential confounding variables (OR 2.4, 95% CI 1.3-4.4, p <.01). In this cross-sectional analysis, elevated cortisol was not associated with worse cardiac function.

CONCLUSIONS

In patients with CHD,depression is associated with elevated cortisol levels.

Dehydroepiandrosterone and allopregnanolone protect sympathoadrenal medulla cells against apoptosis via antiapoptotic Bcl-2 proteins

The neuroactive steroids dehydroepiandrosterone (DHEA), its sulfate ester DHEA sulfate (DHEAS), and allopregnanolone (Allo), produced by the CNS and the adrenals, appear to exert a protective effect in hippocampal and cortical neuron ischemia- and excitotoxicity-induced injury. We hypothesized that they may also play a protective role on the adrenal medulla, an important part of the sympathetic nervous system, and the tissue adjacent to their primary site of production. DHEA, DHEAS, and Allo protected rat chromaffin cells and the rat pheochromocytoma PC12 cell line, an established model for the study of adrenomedullary cell apoptosis and survival, against serum deprivation-induced apoptosis. Their effects were time- and dose-dependent, with EC50 1.8, 1.1, and 1.5 nM, respectively. The antiapoptotic effect of DHEA DHEAS and Allo was compared to that of a long list of structurally related compounds and was found to be structure-specific, confined mainly to conformation 3beta-OH-Delta5 for androstenes and 3alpha-OH for pregnanes. Indeed, 3-keto, Delta4, or C7 hydroxylated androstenes and 3beta pregnanes were ineffective. The prosurvival effect of DHEA(S) and Allo was N-methyl-D-aspartate-, GABAA-, sigma1-, or estrogen receptor-independent. It involved the antiapoptotic Bcl-2 proteins, their role being sine qua non for their action because Bcl-2 antisense oligonucleotides reversed their effects. Finally, DHEA(S) and Allo activated cAMP response element-binding protein and NF-kappaB, upstream effectors of antiapoptotic Bcl-2 protein expression. They also activated the antiapoptotic kinase PKCalpha/beta, a posttranslational activator of Bcl-2 protein. Our findings suggest that decline of DHEA(S) and Allo during aging or stress may leave the adrenal medulla unprotected against proapoptotic challenges.

Stress in the brain: implications for treatment of depression

A fundamental question in stress research is when the glucocorticoid stress hormone (cortisol in man) stops being neuroprotective and becomes harmful to the brain with negative consequences for cognition and mood. To address this question Section 1 focuses on the action mechanism of glucocorticoids. These hormones act via high and low affinity nuclear receptors, which regulate gene transcription in a coordinate manner. The receptors are expressed abundantly in hippocampus, amygdala and frontal cortex involved in cognitive processes. In Section 2 hypercortisolism is considered a potential disease factor for about 50% of the patients suffering from major depression. Recent data show that these patients recover within a few days when excess cortisol action is blocked with high doses of an antiglucocorticoid. Section 3 concerns animal models with 'depression-like' features of hypercorticism generated by manipulation of gene X environment inputs. Using gene expression profiling technology in the hippocampal transcriptome of these animals we identified about 700 potential targets for antidepressants out of 30 000 detectable gene products. One of our models is based on early life programming of the stress system. Rats exposed as pups to maternal deprivation display at senescence an enhanced individual difference in cognitive performance. The maternally deprived senescent animals age either successfully or become senile, at the expense of the average performance of non-deprived controls. The essay is concluded with the notion that the new generation of antidepressants ameliorates specific psychic dysfunctions (e.g. cognitive performance) linked to aberrant stress hormone action in discrete brain regions.

Antiglucocorticoid drugs in the treatment of depression

A confluence of evidence indicates that prolonged elevation in gluco-corticoid level may result in disturbances of mood and cognition. In Cushing's syndrome, hypersecretion of cortisol is associated with a high incidence of depression, impairment in memory and hippocampal atrophy. Pharmacological usage of glucocorticoids is similarly productive of mood change and memory deficit. In patients with endogenous depression, hypercortisolaemia is associated with cognitive dysfunction and possibly a decrease in hippocampal volume. In each of these conditions, reduction of glucocorticoid level, either through discontinuation of steroid treatment or through usage of agents that block glucocorticoid synthesis, ameliorates the adverse behavioural effects. Traditional antidepressant agents may, in addition, stabilise mood through actions on the hypothalamic-pituitary adrenocortical (HPA) system. Although clinical usage of the currently available antiglucocorticoid drugs is limited by significant adverse side effect profiles, development of drugs specifically targeting the glucocorticoid receptor may lead to innovative strategies in the treatment of mood disorders.