Matricaria chamomilla CH12 decreases handling stress in Nelore calves

Matricaria chamomilla CH₁₂ is a phytotherapeutic or homeopathic product, which has been used to reduce stress. Here, we examined its effect on preventing handling stress in bovines. Sixty Nelore calves were randomly distributed into two equal groups. One group was administered Matricaria chamomilla CH₁₂ in diet and the other the 'control' was not. Animals in both groups were maintained unstressed for 30 days to adjust to the feeding system and pasture, and were then stressed by constraint on the 31th, 38th, 45th and 60th experimental days. Blood samples were taken on these days after animals had been immobilization in a trunk contention for 5 min. Stress was followed by analyzing serum cortisol levels. These peaked on the 45th day and then decreased, but not to baseline, on the 60th day. On the 45th day cortisol levels were significantly lower in animals fed Matricaria chamomilla CH₁₂, suggesting that this product reduces stress. These effects may be a consequence of its inhibiting cortisol production and its calming and anxiolytic effects.

The role of tumor necrosis factor-alpha in stress-induced worsening of cerebral ischemia in rats

Whereas stress is known to be one of the risk factors of stroke, few experimental studies have examined the possible mechanisms by which stress may affect stroke outcome. Most of the knowledge on the effects of stress on cerebrovascular disease in humans is restricted to catecholamines and glucocorticoids effects on blood pressure and/or development of atherosclerosis. By using an experimental paradigm consisting of the exposure of Fischer rats to repeated immobilization sessions (1 h daily during seven consecutive days) prior to permanent middle cerebral artery occlusion (MCAO), we have found that stress worsens behavioral outcome and increases infarct size after MCAO. These changes occur concomitantly to an increase in inducible nitric oxide synthase (iNOS) expression and to the accumulation of lipid peroxidation markers in brain tissue. The possible regulatory role of TNFalpha was studied by looking at the mechanisms of release of this cytokine as well as to the expression of its receptors (TNFR1 and 2). The results of the present study suggest an increase in TNFalpha expression and release after stress, as well as an increase in the expression of TNFR1. Pharmacological blockade of TNFalpha with anti-TNFalpha led to a decrease in the infarct size as well as in the oxidative/nitrosative biochemical parameters seen after ischemia. In summary, our results indicate that TNFalpha accounts, at least partly, for the worsening of MCAO consequences in brain of rats exposed to stress. Furthermore, the data presented here provide evidence that stress can increase brain ischemic damage and support a possible protective effect of treatment of stressful situations before and during the development of the brain ischemia.

Evaluation of adaptogenic activity profile of herbal preparation

The herbal formulation, AVM is a proprietary formula that consists of extracts of herbs that have been used in Indian traditional medicine to promote physical and mental health, improve defense mechanisms of the body and enhance longevity. AVM (500 and 1000 mg/kg) was tested for its adaptogenic activity by determining antistress, anabolic and immunomodulatory effects. In antistress activity, pretreatment with AVM significantly attenuated the changes in ascorbic acid (from blood and adrenal), cortisol (from plasma and adrenal) and adrenal gland weights induced due to restrain stress (physical immobilization). Its antistress effect at 1000 mg/kg was comparable to that of diazepam (5 mg/kg) treated group. Leucopenia, and anemia induced by cyclophosphamide (CYP) was shown to reduce significantly by AVM. Treatment of AVM + CYP had increased spleen and thymus weights significantly as compared to CYP alone treated group. The anabolic activity was evaluated by weight gain of the levator ani muscle, ventral prostrate gland and seminal vesicles in rats as compared to untreated control.

Effects of quetiapine on the brain-derived neurotrophic factor expression in the hippocampus and neocortex of rats

The effects of antipsychotics on the brain-derived neurotrophic factor (BDNF) expression have been controversial. This study aimed to investigate the effects of chronic quetiapine administration on the BDNF mRNA expression in hippocampus and neocortex of rats with or without immobilization stress. The chronic administration (21 days) of quetiapine (10 mg/kg) significantly attenuated the decreased BDNF mRNA expression in the both hippocampal and cortical regions of rats caused by immobilization stress, and significantly increased the BDNF mRNA expression in the dentate gyrus of rats even without the immobilization stress. These results could add some theoretical bases to explain why quetiapine may improve cognitive symptoms of schizophrenia by stimulating BDNF mRNA expression.

Limited brain diffusion of the glucocorticoid receptor agonist RU28362 following i.c.v. administration: implications for i.c.v. drug delivery and glucocorticoid negative feedback in the hypothalamic-pituitary-adrenal axis

The experiments described herein present a method for tracking diffusion of the glucocorticoid receptor agonist RU28362 in brain following i.c.v. drug administration. A useful property of glucocorticoid receptor is that it is primarily cytoplasmic when unbound and rapidly translocates to the nucleus when bound by ligand. Thus, removal of endogenous glucocorticoids by adrenalectomy allows us to identify brain regions with activated glucocorticoid receptor after i.c.v. glucocorticoid receptor agonist treatment by examining the presence or absence of nuclear glucocorticoid receptor immunostaining. We have previously demonstrated that an i.p. injection of 150 microg/kg RU28362 1 h prior to restraint stress is sufficient to suppress stress-induced hypothalamic-pituitary-adrenal axis hormone secretion [Ginsberg AB, Campeau S, Day HE, Spencer RL (2003) Acute glucocorticoid pretreatment suppresses stress-induced hypothalamic-pituitary-adrenal axis hormone secretion and expression of corticotropin-releasing hormone hnRNA but does not affect c-fos mRNA or fos protein expression in the paraventricular nucleus of the hypothalamus. J Neuroendocrinol 15:1075-1083]. We report here, however, that in rats i.c.v. treatment with a high-dose of RU28362 (1 microg) 1 h prior to stressor onset does not suppress stress-induced hypothalamic-pituitary-adrenal axis activity. We then performed a series of experiments to examine the possible differences in glucocorticoid receptor activation patterns in brain and pituitary after i.c.v. or i.p. treatment with RU28362. In a dose-response study we found that 1 h after i.c.v. injection of RU28362 (0.001, 0.1 and 1.0 microg) glucocorticoid receptor nuclear immunoreactivity was only evident in brain tissue immediately adjacent to the lateral or third ventricle, including the medial but not more lateral portion of the medial parvocellular paraventricular nucleus of the hypothalamus. In contrast, i.p. injection of RU28362 produced a uniform predominantly nuclear glucocorticoid receptor immunostaining pattern throughout all brain tissue. I.c.v. injection of the endogenous glucocorticoid receptor agonist, corticosterone (1 microg) also had limited diffusion into brain tissue. Time-course studies indicated that there was not a greater extent of nuclear glucocorticoid receptor immunostaining present in brain after shorter (10 or 30 min) or longer (2 or 3 h) intervals of time after i.c.v. RU28362 injection. Importantly, time-course studies found that i.c.v. RU28362 produced significant increases in nuclear glucocorticoid receptor immunostaining in the anterior pituitary that were evident within 10 min after injection and maximal after 1 h. These studies support an extensive literature indicating that drugs have very limited ability to diffuse out of the ventricles into brain tissue after i.c.v. injection, while at the same time reaching peripheral tissue sites. In addition, these studies indicate that significant occupancy of some glucocorticoid receptor within the paraventricular nucleus of the hypothalamus and pituitary is not necessarily sufficient to suppress stress-induced hypothalamic-pituitary-adrenal axis activity.

A centrally acting, anxiolytic angiotensin II AT1 receptor antagonist prevents the isolation stress-induced decrease in cortical CRF1 receptor and benzodiazepine binding

Long-term pretreatment with an angiotensin II AT1 antagonist blocks angiotensin II effects in brain and peripheral organs and abolishes the sympathoadrenal and hypothalamic-pituitary-adrenal responses to isolation stress. We determined whether AT1 receptors were also important for the stress response of higher regulatory centers. We studied angiotensin II and corticotropin-releasing factor (CRF) receptors and benzodiazepine binding sites in brains of Wistar Hannover rats. Animals were pretreated for 13 days with vehicle or a central and peripheral AT1 antagonist (candesartan, 0.5 mg/kg/day) via osmotic minipumps followed by 24 h of isolation in metabolic cages, or kept grouped throughout the study (grouped controls). In another study, we determined the influence of a similar treatment with candesartan on performance in an elevated plus-maze. AT1 receptor blockade prevented the isolation-induced increase in brain AT1 receptors and decrease in AT2 binding in the locus coeruleus. AT1 receptor antagonism also prevented the increase in tyrosine hydroxylase mRNA in the locus coeruleus. Pretreatment with the AT1 receptor antagonist completely prevented the decrease in cortical CRF1 receptor and benzodiazepine binding produced by isolation stress. In addition, pretreatment with candesartan increased the time spent in and the number of entries to open arms of the elevated plus-maze, measure of decreased anxiety. Our results implicate a modulation of upstream neurotransmission processes regulating cortical CRF1 receptors and the GABA(A) complex as molecular mechanisms responsible for the anti-anxiety effect of centrally acting AT1 receptor antagonists. We propose that AT1 receptor antagonists can be considered as compounds with possible therapeutic anti-stress and anti-anxiety properties.

Protective role of caffeic acid phenethyl ester in the liver of rats exposed to cold stress

Cold exposure can induce a form of environmental stress. Cold stress (CS) alters homeostasis, results in the creation of reactive oxygen species and leads to alterations in the antioxidant defense system. The caffeic acid phenethyl ester (CAPE), an active component of propolis, has an antioxidant capacity. We investigated the effect of CS on oxidative stress and antioxidant defense system and the possible protective effect of CAPE in rat liver tissue. Twenty-four female Wistar Albino rats were divided into four groups: Control, CAPE-treated, CS, and CAPE-treated CS (CS + CAPE) group. Catalase (CAT), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) activities and total glutathione (GSH) and malondialdehyde (MDA) levels were measured. In addition, histological changes in liver tissue were examined by light microscopy. SOD, CAT and GSH-Px activities and total GSH level were significantly declined in the CS group. In the CS + CAPE group, the activities of these three enzymes and GSH level significantly raised with regard to the CS group. MDA levels increased in the CS group and decreased in the CS + CAPE group. The tissues of the CS group showed some histopathological changes such as necrosis, hepatocyte degeneration, sinusoidal dilatation, hemorrhage and vascular congestion and dilatation. In the CS + CAPE group, the histopathological evidence of hepatic damage was markedly reduced. Histological parameters were consistent with biochemical parameters. In this study, CS increased oxidative stress in liver tissue. CAPE regulated antioxidant enzymes, inhibited lipid peroxidation and reduced hepatic damage.

Augmentation and proliferation of T lymphocytes and Th-1 cytokines by Withania somnifera in stressed mice

Stress has been associated with reports of both greater severity and prolongation of diseases in patients with the infectious origin as well as other immune-mediated diseases. Withania somnifera, an Indian medicinal plant used widely in the treatment of many clinical conditions in India, was investigated for its anti-stress properties using BALB/c mice subjected to chronic stress. The study aimed to investigate chronic stress-induced alterations on Th1 lymphocyte subset distribution and corresponding cytokine secretion patterns. Oral administration of chemically standardized and identified aqueous fraction of W. somnifera root (WS) at the graded doses of 25, 50, 100 and 200 mg/kg p.o. caused significant increase in the stress-induced depleted T-cell population and increased the expression of Th1 cytokines in chronically stressed mice.

Prolonged decrease in stress reactivity caused by dehydroepiandrosterone sulfate

In male rats exposed to repeated stress, the decrease in stress reactivity produced by subcutaneous injection of dehydroepiandrosterone sulfate (recorded by the decrease in stress-induced concentrations of corticosterone and adrenocorticotropic hormone in blood plasma) was observed 1-6 days postinjection and involved central regulatory mechanisms.

Immobilization stress causes extra-cellular oxidant-antioxidant imbalance in rats: restoration by L-NAME and vitamin E

Stress has been shown to be associated with altered homeostasis that may lead to oxidant-antioxidant imbalance. Non-enzymatic antioxidants are important regulators of reactive oxygen species produced in extra-cellular milieu and represent the first line of defense against them. Extra-cellular non-enzymatic antioxidants may be disturbed by the production of superoxide and nitric oxide and this has not been studied in stressful situation previously. In the present study, effects of immobilization stress (IS), both acute (IS x 1) and repeated (IS x 7) were assessed on extra-cellular total antioxidant capacity measured as plasma ferric reducing antioxidant power (FRAP) and protein sulfhydryls, and oxidative stress measured as leukocyte superoxide generation, plasma nitric oxide production (total nitrates and nitrites, NOx) and lipid peroxides in rats. Effects of pretreatment with nitric oxide synthase (NOS) inhibitors and vitamin E were also studied on these biochemical parameters. The results showed that both IS x 1 and IS x 7 resulted in extra-cellular oxidant-antioxidant imbalance as oxidant generation was increased and non-enzymatic antioxidants were depleted. Pretreatment either with NOS inhibitors or vitamin E restored stress-induced extracellular oxidant-antioxidant imbalance implying their potential role as antioxidants. Our data suggest that there is extra-cellular oxidant-antioxidant imbalance in the stressed rats, with greater magnitude of severity in repeated stress paradigm. Augmentation of antioxidant defenses might be beneficial in long-term stress.

Clonidine-ephedrine combination reduces pain on injection of propofol and blunts hemodynamic stress responses during the induction sequence

STUDY OBJECTIVES

To evaluate the effects of clonidine and ephedrine on propofol-induced pain and on hemodynamic changes during the induction sequence.

DESIGN

This was a prospective, randomized, double-blind study.

SETTING

The study was conducted at a university hospital.

PATIENTS

200 ASA physical status I or II adult patients scheduled for elective surgery.

INTERVENTIONS

Patients were randomly allocated to one of 4 groups (50 patients per group): clonidine-ephedrine (CE), clonidine-saline (CS), diazepam-ephedrine (DE), and diazepam-saline (DS). Thirty seconds after the administration of ephedrine or saline, propofol 2 mg/kg was infused at a rate of 18.3 mL/min.

MEASUREMENTS

Patients were asked whether they had pain due to propofol injection. A blinded investigator evaluated the pain score: 0 = no pain, 1 = mild pain, 2 = severe pain without behavioral signs such as grimace or arm withdrawal movement, and 3 = severe pain accompanied by behavioral signs. Mean arterial blood pressure (MAP) and heart rate (HR) were measured at 1-minute intervals from just before the administration of ephedrine or saline to 5 minutes after the tracheal intubation.

MAIN RESULTS

Median pain score in CE was significantly lower than those in the other groups (P < 0.0001). Pain scores in CS and DE were significantly lower than that in DS (P < 0.05). Ephedrine increased HR in CE and DE (P < 0.05), but clonidine did not augment the effect. Mean arterial blood pressure before tracheal intubation decreased to comparable values in all groups. After the intubation, mean arterial blood pressure and HR in CE and CS were significantly lower than those in DE and DS (P < 0.05).

CONCLUSIONS

Combination of clonidine and ephedrine effectively reduced propofol-induced pain, but did not prevent propofol-induced hypotension. Clonidine did not augment low dose of ephedrine-induced increase in HR and produced stable hemodynamic condition during the induction sequence.

Ephedrine-caffeine mixture in wet-cold stress

Our investigations were aimed at studying the possibility of enhancement of homeostatic processes protecting against excessive body cooling by using thermogenic drugs. We studied the influence of ephedrine (1 mg/kg) and caffeine (2.5 mg/kg) mixture in males immersed in cold water (12 degrees C) on core temperature and plasma catecholamines, cortisol, energy substrates and chosen cognitive functions in subjects without or after previous submission to short cold acclimation procedure by five repeated brief cold-water immersions. The tested drugs did not significantly influence core temperature during immersion both in acclimated and non-acclimated subjects, however, they enhanced metabolic response. There were observed faster mobilization and higher increase in energy substrates, more pronounced in acclimated subjects (free fatty acids, glucose). Tested drugs slightly improved some psychosomatic reactions. Although the results of our study suggest that a single application of ephedrine-caffeine mixture might probably support physiological mechanisms protecting against excessive body cooling when used in people in wet-cold conditions, further research is needed to confirm the clinical significance.

Gonadal steroids in critical illness

Gonadal steroids are metabolized in target cells and then interact with specific receptors to exert genomic and nongenomic effects. Complex feedback loops that involve the immune-neuroendocrine axis, limbic system, and gonadal steroids play a vital role in the adaptation to critical illness. Preclinical studies demonstrate adverse physiological effects of androgens on the cardiovascular and immune systems despite its purported anabolic effects. Similar models also demonstrate salutary effects of estrogens on these systems. Thus, during the catabolic phases of acute and chronic critical illness, estrogen, and not androgen, therapy may prove to be a valuable intervention. However, during the post-critical illness recovery phase, when anabolism is critical, androgen therapy may still be useful and safe.

Changes within the thyroid axis during critical illness

Pronounced alterations in plasma thyroid stimulating hormone and thyroid hormone levels occur during critical illness without any evidence for thyroid disease. Plasma T3 decreases and plasma rT3 increases within a few hours after the onset of disease, and the magnitude of these changes is related to the severity and the duration of the disease. This article reviews the mechanisms behind the observed changes, and focuses on the regulation of thyroid hormone deiodination and transport, as well as the potential positive or negative effects for both the acute and the chronic phase of critical illness.

Catecholamines and vasopressin during critical illness

In critical care medicine, catecholamines are most widely used to reverse circulatory dysfunction and thus to restore tissue perfusion. However, catecholamines not only influence systemic and regional hemodynamics, but also exert a variety of significant metabolic, endocrine, and immunologic effects. Arginine vasopressin is a vasomodulatory hormone with potency to restore vascular tone in vasodilatory hypotension. Although the evidence supporting the use of low doses of vasopressin or its analogs in vasodilatory shock is increasing, lack of data regarding mortality and morbidity prevent their implementation in critical care protocols.

Correction of cerebral ischemia in low-resistant animals with an antistress drug Deltaran

Deltaran decreased the amplitude of EEG slow waves and restored neuronal reactivity after carotid artery occlusion in Wistar rats sensitive to cerebral ischemia. Deltaran had no effect on local cerebral blood flow. This drug increased blood supply to a unit of neuronal activity in the brain of intact animals during the acute stage of cerebral ischemia, provided 100% survival rate of rats with cerebral ischemia, and prevented the development of neurological symptoms in survivors. Animal experiments proved the possibility of correcting cerebral ischemia with antistress drug Deltaran.

[Tofisopam and melatonin attenuate the reorganization of circadian locomotor rhythm in rats under injection-induced stress conditions]

Repeated saline injections induce reorganization of the circadian locomotor rhythm in rats, which is manifested by increased amplitude, enhanced instability of the acrophase, and changed spectral characteristics. The benzodiazepine anxiolytic tofisopam (grandaxin, 10 mg/kg) and the pineal hormone melatonin (0.1 mg/kg) prevented the stress-induced changes in the circadian rhythm. The hormone exhibited a more optimal chronotropic activity than grandaxin.

Effects of repeated tianeptine treatment on CRF mRNA expression in non-stressed and chronic mild stress-exposed rats

Accumulating evidence suggests that dysregulation of corticotropin-releasing factor (CRF) may play a role in depression and that this dysregulation may be corrected by antidepressant drug treatment. Here, we examined whether chronic mild stress (CMS) alters CRF mRNA levels in stress-related brain areas including the bed nucleus of the stria terminalis (BNST) and the central nucleus of amygdala (CeA), and whether repeated tianeptine treatment can attenuate CMS-induced changes in CRF mRNA levels. Male rats were exposed to CMS for 19 days, and control animals were subjected to brief handling. Both groups were injected daily with tianeptine or saline. CMS significantly increased CRF mRNA levels in the dorsal BNST (dBNST), but not in other areas. Repeated tianeptine treatment prevented the CMS-induced increase in CRF mRNA levels in the dBNST, and reduced CRF mRNA levels in dBNST in non-stressed controls. Moreover, repeated tianeptine treatment significantly decreased CRF mRNA levels in the ventral BNST and CeA of non-stressed controls as well as CMS-exposed rats. These results show that CMS induces a rather selective increase of CRF mRNA in the dBNST. In addition, these results suggest that repeated tianeptine treatment diminishes the basal activity of CRF neurons and reduces their sensitivity to stress.

Stress-inducing effect of hypoxia of different origin and its correction with Inula Helenium L. tincture

In order to evaluate the severity of stress, the effects of single and repeated exposure to hypoxia of different origin (hemic, tissue, and circulatory) on the classical parameters of the Selye triad, cytological characteristics of lymphoid organs, and karyometric parameters (nucleus diameters) were studied in all adrenal zones, and analysis of correlations was carried out. The corrective effect of Inula helenium L. tincture manifested in prolongation of the life-span and normalization of somatic and morphological parameters.

Association between Adrenal Insufficiency and Ventilator Weaning

RATIONALE

Adrenal insufficiency is a common disorder in critically ill patients with mechanical ventilation and is usually associated with higher mortality and poor clinical outcome.

OBJECTIVES

To determine whether stress dose corticosteroid supplementation can improve ventilator weaning and clinical outcome in patients with adrenal insufficiency.

METHODS

A prospective, randomized, placebo controlled, double-blinded study was conducted in the intensive care unit of a tertiary teaching hospital. A total of 93 mechanically ventilated patients were enrolled in the ventilator weaning trial. Adrenal function was assessed in all patients. Patients with adrenal insufficiency were randomized to the treatment group (50 mg intravenous hydrocortisone every 6 h) and the placebo group.

MEASUREMENTS AND MAIN RESULTS

The successful ventilator weaning percentage was significantly higher in the adequate adrenal reserve group (88.4%) and in the stress dose hydrocortisone treatment group (91.4%) than in the placebo group (68.6%). The weaning period was shorter in the hydrocortisone treatment group than in the placebo group. No significant adverse effects were observed in the corticosteroid treatment group.

CONCLUSIONS

For patients with respiratory failure, early identification of adrenal insufficiency and appropriate supplementation with stress dose hydrocortisone increase the success of ventilator weaning and shortens the weaning period.

Glutamine: do the data support the cause for glutamine supplementation in humans?

This review examines the preclinical rationale for using glutamine supplements and reviews the prospective randomized trials using glutamine to improve outcomes in patients. A special role for glutamine in gut physiology and in management of a variety of serious illnesses has been suggested, because it is the most abundant extracellular amino acid, and is used at high rates by the gut, liver, central nervous system, and immune cells. A state of relative Gln deficiency has been postulated in humans based on the decrease in plasma Gln in acute critical illness, but the decrease in plasma Gln is not specific for that amino acid, predicts only poorer outcome, and has not been validated to identify a deficiency state. Current evidence does not necessarily predict a special need or role for Gln in critical illness. Clinical efficacy of supplemental Gln has been difficult to demonstrate, possibly related to the lack of a Gln deficiency state, the wide range of end points used that reflect the lack of certainty of the predicted effect of supplementation, the heterogeneous patient populations studied, the lack of stable clinical course during the study, the lack of adequate power, and the relatively short follow-up period. Prospective randomized clinical trials of Gln supplementation were reviewed in patients with short-bowel syndrome, during cancer chemotherapy and in bone marrow transplantation, and in surgical, burn, and intensive care unit patients. No firm recommendation can be made at this time. Future studies should seek to develop a more standard and stable design for intervention in sufficiently powered studies.

St john's wort (Hypericum perforatum) counteracts deleterious effects of the chronic restraint stress on recall in rats

This study aimed at verifying a hypothesis that St. John's wort (Hypericum perforatum) alleviates stress-induced memory impairments. Administration of Hypericum perforatum (350 mg kg(-1) daily for 21 days) significantly enhanced recall of passive avoidance behavior (PAB), but had no effect on the acquisition of conditioned avoidance responses (CARs). Rats stressed chronically (2 h daily for 21 days) displayed diminished recall of the PAB and this effect was abolished by St John's wort. Chronic administration of the "equivalent" to the stress dose of exogenous corticosterone (5 mg kg(-1) daily for 21 days) also impaired recall of PAB, and this effect was also reversed by Hypericum perforatum. None of our treatments produced significant motor coordination impairments as tested in a 'chimney' test. It appears that H. perforatum prevents stress-induced deterioration of memory in rats.

Hippocampal neurogenesis: Opposing effects of stress and antidepressant treatment

The hippocampus is one of several limbic brain structures implicated in the pathophysiology and treatment of mood disorders. Preclinical and clinical studies demonstrate that stress and depression lead to reductions of the total volume of this structure and atrophy and loss of neurons in the adult hippocampus. One of the cellular mechanisms that could account for alterations of hippocampal structure as well as function is the regulation of adult neurogenesis. Stress exerts a profound effect on neurogenesis, leading to a rapid and prolonged decrease in the rate of cell proliferation in the adult hippocampus. In contrast, chronic antidepressant treatment up-regulates hippocampal neurogenesis, and could thereby block or reverse the atrophy and damage caused by stress. Recent studies also demonstrate that neurogenesis is required for the actions of antidepressants in behavioral models of depression. This review discusses the literature that has lead to a neurogenic hypothesis of depression and antidepressant action, as well as the molecular and cellular mechanisms that underlie the regulation of adult neurogenesis by stress and antidepressant treatment.

Immobilization stress induces cell death through production of reactive oxygen species in the mouse cerebral cortex

Prolonged stress has been shown to impair brain function and increase vulnerability to neuronal injury. To elucidate the in vivo response of neuronal cells to induced stress, we immobilized mice by binding their legs. Levels of reactive oxygen species (ROS) in the cerebral cortex were increased after stress induction. NADPH oxidase, interleukin-1beta (IL-1beta) and cyclooxygenase 2 mRNA (COX-2) expression levels were upregulated, and Fas levels were also increased. The increased expression of these factors was associated with neuronal death, which was confirmed by TUNEL and NeuN staining. OX42 staining was also evident around the TUNEL-stained lesions. From these findings, it appears that immobilization stress induces neuronal death in the mouse cerebral cortex, a process mediated by NADPH oxidase, IL-1beta, COX-2, ROS and Fas. However, this could be inhibited by pretreating the animals with antioxidants such as ebselen or pyrrolidine dithiocarbamate.

Treatment with GH and IGF-1 in Critical Illness

Trauma, sepsis, and surgery are associated with global hypercatabolism and a negative nitrogen balance. When critical illness is prolonged the relentless loss of lean tissue becomes functionally important. Protein catabolism in the critically ill patient is associated with complex changes in the growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis. Many small clinical studies indicate that treatment with recombinant human (rh) GH would be a safe and effective means of limiting the deleterious effects of the catabolic response. Unexpectedly, however, two large prospective randomized controlled trials (PRCTs) demonstrated that administration of rhGH to long-stay critically ill adults increases morbidity and mortality. Some progress has been made in understanding the mechanisms underlying this observation.

Quetiapine and venlafaxine synergically regulate heme oxygenase-2 protein expression in the hippocampus of stressed rats

HO-2 is a constitutive isoform of heme oxygenase (HO), a microsomal enzyme that catalyzes the cleavage of the heme ring to form ferrous iron, carbon monoxide, and biliverdin. In contrast to HO-1, which is inducible, HO-2 is not responsive to stimuli tested to date except for prolonged exposure to the adrenal glucocorticoids (GCs). Previous studies have shown that high GC concentrations or stress damage or kill hippocampal neurons. In the present study, it was found that chronic restraint stress decreased HO-2 protein levels in hippocampal neurons, as demonstrated by immunohistochemistry and Western blot analysis. Moreover, our results showed that the combination of 2.5mg/kg of venlafaxine and 5mg/kg of quetiapine effectively prevented the HO-2 protein decrease in hippocampal neurons of stressed rats, whereas either of the drugs alone did not show any effect. At higher dose levels, both quetiapine (10mg/kg) and venlafaxine (5mg/kg) produced significant effects comparable to that of their combination. Quetiapine is an atypical antipsychotic and venlafaxine an antidepressant. In previous studies, these two drugs have been shown to prevent or protect against the stress-induced decrease in hippocampal neurogenesis and BDNF expression. These data suggest that both quetiapine and venlafaxine share the hippocampus as their common target by enhancing hippocampal resilience, which may be impaired in patients with schizophrenia or depression.

Nociceptin/orphanin FQ: pain, stress and neural circuits

First isolated some 10 years ago as the endogenous ligand for the "orphan opioid receptor" (ORL-1, now designated NOP), nociceptin/orphanin FQ (N/OFQ) has proved to be a potent inhibitory neuropeptide found across the neuraxis. Because of the homologies between opioids and N/OFQ, functional studies of this peptide have focused most heavily on pain and analgesia. This behavioral literature has been marked by a lack of consistency across laboratories, but much of the data can be explained by considering the potent inhibitory actions of N/OFQ in well-defined modulatory circuits. Presently, the most closely studied such circuit is the rostral ventromedial medulla (RVM), where administration of N/OFQ can block opioid analgesia (by inhibiting opioid-activated pain-inhibiting neurons), but under other conditions produces apparent hypoalgesia (by inhibiting pain-facilitating neurons). The net behavioral effect of N/OFQ in the RVM thus depends on whether experimental conditions are such that the pain-facilitating or pain-inhibiting neurons are active at the time the peptide is given. An important recent finding is that N/OFQ antagonists have antinociceptive properties when given supra-spinally. Although the likelihood of interactions between stress and analgesia systems must be considered in interpreting these data, they suggest that N/OFQ antagonists have potential as clinically useful analgesic drugs.

Effects of lactoferrin on the immune response modified by the immobilization stress

Effects of orally administered lactoferrin (LF) on the cellular and humoral immune responses in mice subjected to immobilization stress (IS) were investigated. Here, we demonstrate that long-term IS induced significant suppression of cellular and humoral immune responses in CBAmice. The suppression was attenuated by LF given to mice in drinking water as determined by the number of antibody-forming cells (AFC) in the spleen and the magnitude of delayed type of hypersensitivity (DTH). On the other hand, LF lowered the elevated DTH response in mice exposed to short-term IS (5 h only) on the day of elicitation of the DTH reaction. We also showed that LF up-regulated spontaneous transforming growth factor beta (TGF-beta) production in the cultures of mesenteric lymph node cells derived from short-term stressed mice. This is the first report on the regulatory effect of LF on the immune response modified by the psychic stress and is consistent with other reports on antinociceptive and analgesic actions of LF in experimental animals.

Management of adrenal insufficiency in different clinical settings

Adrenal insufficiency is a rare disease, but its prevalence is increasing. The most frequent cause of primary adrenal insufficiency in western countries is autoimmune adrenalitis, whereas secondary adrenal insufficiency is most often caused by pituitary tumours and their treatment (e.g., surgery). Chronic glucocorticoid replacement consists of hydrocortisone 15-25 mg/day in divided doses and dose monitoring is largely based on clinical judgement. Fludrocortisone 0.05-0.2 mg/day is given for substitution in mineralocorticoid deficiency aiming at normotension, normokalaemia and a plasma renin activity in the upper normal range. It has recently been shown that, despite adequate glucocorticoid and mineralocorticoid replacement well being in patients with adrenal insufficiency is still impaired. Several studies have demonstrated that dehydroepiandosterone 25-50 mg/day p.o. may improve mood, fatigue, well-being and, in women, also sexuality, suggesting that dehydroepiandosterone should become part of the standard treatment regime. However, large Phase III trials of dehydroepiandosterone for adrenal insufficiency are still lacking and it has not yet been approved for the treatment of this disease. Patients with adrenal insufficiency are at risk of adrenal crisis, usually precipitated by major stress, such as severe infection or surgery. Early dose adjustments are required to cover the increased glucocorticoid demand in stress. Careful and repeated education of patients and their partners is the best strategy to avoid this life-threatening emergency. Some recent studies suggest that during sepsis some patients with intact adrenal function may develop transient relative adrenal insufficiency and benefit from administration of hydrocortisone plus fludrocortisone. However, the pathophysiology and diagnosis criteria of relative adrenal insufficiency and its treatment remain unsettled issues.

Neurotrophic factors and regulation of mood: role of exercise, diet and metabolism

Results from basic and clinical studies demonstrate that stress and depression decrease neurotrophic factor expression and neurogenesis in brain, and that antidepressant treatment blocks or reverses these effects, leading to a neurotrophic hypothesis of depression. Neurotrophic factor expression and neurogenesis are also decreased during aging and could be risk factors for depression. In contrast, exercise and enriched environment increase neurotrophic support and neurogenesis, which could contribute to the blockade of the effects of stress and aging and produce antidepressant effects. A brief overview of this work and the specific neurotrophic factors involved are discussed in this review.

Agmatine attenuates stress- and lipopolysaccharide-induced fever in rats

Physiological stress evokes a number of responses, including a rise in body temperature, which has been suggested to be the result of an elevation in the thermoregulatory set point. This response seems to share similar mechanisms with infectious fever. The aim of the present study was to investigate the effect of agmatine on different models of stressors [(restraint and lipopolysaccharide (LPS)] on body temperature. Rats were either restrained for 4 h or injected with LPS, both of these stressors caused an increase in body temperature. While agmatine itself had no effect on body temperature, treatment with agmatine (20, 40, 80 mg/kg intraperitoneally) dose dependently inhibited stress- and LPS-induced hyperthermia. When agmatine (80 mg/kg) was administered 30 min later than LPS (500 microg/kg) it also inhibited LPS-induced hyperthermia although the effect became significant only at later time points and lower maximal response compared to simultaneous administration. To determine if the decrease in body temperature is associated with an anti-inflammatory effect of agmatine, the nitrite/nitrate levels in plasma was measured. Agmatine treatment inhibited LPS-induced production of nitrates dose dependently. As an endogenous molecule, agmatine has the capacity to inhibit stress- and LPS-induced increases in body temperature.

Free Radical Oxidation in Rat Brain during Chronic Stress and Pharmacological Regulation of This Process

We studied free radical oxidation in the brain and blood serum from experimental animals exposed to chronic stress and receiving psychotropic drugs (phenazepam, Atarax, Fluanxol, and valerian). Chronic stress was accompanied by activation of free radical oxidation, which could be modulated by psychotropic drugs.

Brain angiotensin II: new developments, unanswered questions and therapeutic opportunities

1. There are two Angiotensin II systems in the brain. The discovery of brain Angiotensin II receptors located in neurons inside the blood brain barrier confirmed the existence of an endogenous brain Angiotensin II system, responding to Angiotensin II generated in and/or transported into the brain. In addition, Angiotensin II receptors in circumventricular organs and in cerebrovascular endothelial cells respond to circulating Angiotensin II of peripheral origin. Thus, the brain responds to both circulating and tissue Angiotensin II, and the two systems are integrated. 2. The neuroanatomical location of Angiotensin II receptors and the regulation of the receptor number are most important to determine the level of activation of the brain Angiotensin II systems. 3. Classical, well-defined actions of Angiotensin II in the brain include the regulation of hormone formation and release, the control of the central and peripheral sympathoadrenal systems, and the regulation of water and sodium intake. As a consequence of changes in the hormone, sympathetic and electrolyte systems, feed back mechanisms in turn modulate the activity of the brain Angiotensin II systems. It is reasonable to hypothesize that brain Angiotensin II is involved in the regulation of multiple additional functions in the brain, including brain development, neuronal migration, process of sensory information, cognition, regulation of emotional responses, and cerebral blood flow. 4. Many of the classical and of the hypothetical functions of brain Angiotensin II are mediated by stimulation of Angiotensin II AT1 receptors. 5. Brain AT2 receptors are highly expressed during development. In the adult, AT2 receptors are restricted to areas predominantly involved in the process of sensory information. However, the role of AT2 receptors remains to be clarified. 6. Subcutaneous or oral administration of a selective and potent non-peptidic AT1 receptor antagonist with very low affinity for AT2 receptors and good bioavailability blocked AT1 receptors not only outside but also inside the blood brain barrier. The blockade of the complete brain Angiotensin II AT1 system allowed us to further clarify some of the central actions of the peptide and suggested some new potential therapeutic avenues for this class of compounds. 7. Pretreatment with peripherally administered AT1 antagonists completely prevented the hormonal and sympathoadrenal response to isolation stress. A similar pretreatment prevented the development of stress-induced gastric ulcers. These findings strongly suggest that blockade of brain AT1 receptors could be considered as a novel therapeutic approach in the treatment of stress-related disorders. 8. Peripheral administration of AT1 receptor antagonists strongly affected brain circulation and normalized some of the profound alterations in cerebrovascular structure and function characteristic of chronic genetic hypertension. AT1 receptor antagonists were capable of reversing the pathological cerebrovascular remodeling in hypertension and the shift to the right in the cerebral autoregulation, normalizing cerebrovascular compliance. In addition, AT1 receptor antagonists normalized the expression of cerebrovascular nitric oxide synthase isoenzymes and reversed the inflammatory reaction characteristic of cerebral vessels in hypertension. As a consequence of the normalization of cerebrovascular compliance and the prevention of inflammation, there was, in genetically hypertensive rats a decreased vulnerability to brain ischemia. After pretreatment with AT1 antagonists, there was a protection of cerebrovascular flow during experimental stroke, decreased neuronal death, and a substantial reduction in the size of infarct after occlusion of the middle cerebral artery. At least part of the protective effect of AT1 receptor antagonists was related to the inhibition of the Angiotensin II system, and not to the normalization of blood pressure. These results indicate that treatment with AT1 receptor antagonists appears to be a major therapeutic avenue for the prevention of ischemia and inflammatory diseases of the brain. 9. Thus, orally administered AT1 receptor antagonists may be considered as novel therapeutic compounds for the treatment of diseases of the central nervous system when stress, inflammation and ischemia play major roles. 10. Many questions remain. How is brain Angiotensin II formed, metabolized, and distributed? What is the role of brain AT2 receptors? What are the molecular mechanisms involved in the cerebrovascular remodeling and inflammation which are promoted by AT1 receptor stimulation? How does Angiotensin II regulate the stress response at higher brain centers? Does the degree of activity of the brain Angiotensin II system predict vulnerability to stress and brain ischemia? We look forward to further studies in this exiting and expanding field.

Amygdalar inactivation blocks stress-induced impairments in hippocampal long-term potentiation and spatial memory

Electrolytic lesions to the amygdala, a limbic structure implicated in stress-related behaviors and memory modulation, have been shown to prevent stress-induced impairments of hippocampal long-term potentiation (LTP) and spatial memory in rats. The present study investigated the role of intrinsic amygdalar neurons in mediating stress effects on the hippocampus by microinfusing the GABA(A) receptor agonist muscimol into the amygdala and examining stress effects on Schaffer collateral/commissural-CA1 LTP and spatial memory. The critical period of the amygdalar contribution to stress effects on hippocampal functions was determined by applying muscimol either before stress or immediately after stress. Our results indicate that intra-amygdalar muscimol infusions before uncontrollable restraint-tailshock stress effectively blocked stress-induced physiological and behavioral effects. Specifically, hippocampal slices prepared from vehicle-infused stressed animals exhibited markedly impaired LTP, whereas slices obtained from muscimol-infused stressed animals demonstrated robust LTP comparable with that of unstressed animals. Correspondingly, vehicle-infused stressed animals displayed impaired spatial memory (on a hidden platform version of the Morris water maze task), whereas muscimol-infused stressed animals revealed unimpaired spatial memory. In contrast to prestress muscimol effects, however, immediate poststress infusions of muscimol into the amygdala failed to interfere with stress impairments of LTP and spatial memory. Together, these results suggest that the amygdalar neuronal activity during stress, but not shortly after stress, is essential for the emergence of stress-induced alterations in hippocampal LTP and memory.

Attenuation of stress-elicited brain catecholamines, serotonin and plasma corticosterone levels by calcined gold preparations used in Indian system of medicine

Problems associated with mental health have increased tremendously in modern times. The search for effective and safe alternatives should, therefore, be pursued vigorously. Forced immobilization is one of the best explored models of stress in rats and the role of corticosterone, serotonin (5-HT) and catecholamines, i.e. norepinephrine, epinephrine, dopamine is well documented. We investigated the therapeutic potential of two gold preparations (Ayurvedic Swarna Bhasma and Unani Kushta Tila Kalan) in restraint induced stress at different time points of 1 hr, 2 hr and 4 hr. We pretreated rats with two gold preparations, Ayurvedic Swarna Bhasma and Unani Kushta Tila Kalan (25 mg/kg, orally for 10 days) prior to restraint stress. Brain catecholamine, serotonin and plasma corticosterone levels were determined following 1, 2 and 4 hr restraint stress, using HPLC and also plasma corticosterone using luminescence spectrophotometry. Gold preparations restored restraint stress-induced elevation in levels of brain catecholamines (norepinephrine, epinephrine and dopmine), 5-HT and plasma corticosterone to near normal levels. Gold, widely used in modern medicine for the treatment of rheumatoid arthritis, is highly valued for various medicinal uses in Indian systems of medicine. Traditional gold preparations are attributed with tonic/rejuvenating and antioxidant properties. Our earlier studies revealed interesting analgesic, immunostimulant, adaptogenic and glycogen sparing properties in these preparations, but their effects in stress and depression have not been investigated yet. Significant restoration of altered values to near normal levels suggest potentials for gold preparations in stress and depression.

Effects of melatonin on 3-nitrotyrosine formation and energy charge ratio in guinea pig kidney in LPS-induced stress

The aim of this study was to evaluate the effects of Escherichia coli-derived lipopolysaccharide on guinea pig kidney by measuring the energy charge ratio and 3-nitrotyrosine levels. In addition the possible protective role of melatonin against lipopolysaccharide-mediated peroxynitrite formation and energy depletion of kidney was determined. Guinea pigs were either pretreated with melatonin or saline (for the control) followed by intraperitoneal administration of E. coli. Six hours after the administration of E. coli, guinea pig kidney ATP, ADP, AMP and 3-nitrotyrosine levels were measured by reverse-phase high performance liquid chromatography. There was a significant increase in the formation of 3-nitrotyrosine and decrease in energy charge in the endotoxin-induced group. However melatonin administration prevented 3-nitrotyrosine formation while failing to prevent or restore changes in the energy charge ratio of the kidney.

Transport stress in Southern chamois (Rupicapra pyrenaica) and its modulation by acepromazine

Chamois have been translocated for more than 100 years but their stress response to transport remains to be elucidated. In this study, 21 free-ranging Southern chamois were captured, physically restrained and then transported. The animals were randomly injected intramuscularly with acepromazine (nine adult males, one adult female and one yearling male) or saline (five adult males, two adult females and three yearling males). Heart rate and body temperature were monitored with telemetric devices, and blood samples were obtained at capture, immediately before and immediately after transport to determine haematological and serum biochemical parameters. Heart rate and blood parameters (erythrocytes, haemoglobin, packed cell volume, leukocytes, monocytes, band neutrophils, lactate, muscular enzymes and creatinine) indicated that transport was more stressful than previous physical restraint. Acepromazine reduced the adverse consequences of transport stress, as demonstrated by heart rate, body temperature, cortisol, creatinine, muscular enzymes, urea, sodium and potassium.

[Arctic teleost fishes with canceled accelerated senescence program are a potential source of stress protectors and cancer drugs]

A new approach to the development of natural cancer drugs from hydrobionts selected for longevity and stress resistance is analyzed. The accelerated senescence program was successfully canceled in holarctic stickleback Gasterosteus aculeatus by crossing the marine and freshwater forms in ponds and selection of hybrids. Prolongation of fish life was accompanied by an increased production of the antistress exocrine secretion by the renal epithelium of male sticklebacks (glycoproteins, peptides, and mucoids), required for successful egg development. Trials of the biologic prepared from this secretion in salmons with epithelioma, guinea pigs with affected skin, and mice with transplantable tumors demonstrated a good therapeutic effect of the biologic.

Remodeling chromatin and stress resistance in the central nervous system: histone deacetylase inhibitors as novel and broadly effective neuroprotective agents

Acetylation and deacetylation of histone protein plays a critical role in regulating gene expression in a host of biological processes including cellular proliferation, development, and differentiation. Accordingly, aberrant acetylation and deacetylation resulting from the misregulation of histone acetyltransferases (HATs) and/or histone deacetylases (HDACs) has been linked to clinical disorders such as Rubinstein-Taybi syndrome, fragile X syndrome, leukemia, and various cancers. Of significant import has been the development of small molecule HDAC inhibitors that permit pharmacological manipulation of histone acetylation levels and treatment of some of these diseases including cancer. In this Review we discuss evidence that aberrant HAT and HDAC activity may also be a common underlying mechanism contributing to neurodegeneration during acute and chronic neurological diseases, including stroke, Huntington's disease Amyotrophic Lateral Sclerosis and Alzheimer's disease. With this in mind, a number of studies examining the use of HDAC inhibitors as therapy for restoring histone acetylation and transcriptional activation in in vitro and in vivo neurodegenerative models are discussed. These studies demonstrate that pharmacological HDAC inhibition is a promising therapeutic approach for the treatment of a range of central nervous system disorders.

St John's wort (Hypericum perforatum) diminishes cognitive impairment caused by the chronic restraint stress in rats

In this study we tested the hypothesis that St John's wort (Hypericum perforatum) may counteract stress-induced memory impairment. Object recognition test and Morris water maze were used to determine whether administration of H. perforatum (350 mg kg(-1) for 21 days), standardized to 0.3% hypericin content, protects against non-spatial and/or spatial memory impairments due to chronic restraint stress (2h daily for 21 days). A group of rats administered the exogenous corticosterone at the dose of 5 mg kg(-1) daily for 21 days, yielding its similar plasma levels as these observed in stress was run in parallel. In the first experiment all rats were tested for recognition memory in the object recognition test. On the following day, the animals were tested in open field and elevated "plus" maze to control for the contribution of respectively, motor and emotional effects of our treatments to the memory tests. In the second experiment, new group of stressed animals was tested for spatial memory in the water maze. We observed that H. perforatum prevented the deleterious effects of both chronic restraint stress and long-term corticosterone on learning and memory as measured in both, the object recognition and the water maze tests. The herb not only prevented stress- and corticosterone-induced memory impairments, but it significantly improved recognition memory (p<0.01) in comparison to control. These results suggest that H. perforatum has a potential to prevent stress memory disorders.

Effect of bosentan (ETA/ETB receptor antagonist) on metabolic changes during stress and diabetes

Elevated plasma ET-1 levels have been reported in several conditions such as stress and diabetes. ET-1 is found to cause insulin resistance and to stimulate liver glycogenolysis. The question arises whether ET-1 has a role in the metabolic changes occurring in such conditions. To test this, we studied the possible effect of the endothelin receptor antagonist, bosentan (50 and 100 mg kg(-1)) on serum glucose and insulin levels as well as on liver glycogen contents in normoglycemic stressed animals. In addition, the effect of bosentan on serum glucose and insulin levels in both mild and severely diabetic rats and its effect on insulin-induced hypoglycemia were also determined. Restraining water immersion stress was used as a model for severe stress reported to elevate plasma ET-1 level. Mild diabetes was induced in rats by intraperitoneal injection of a low dose of streptozotocin (38 mg kg(-1)) while severe diabetes was induced by intraperitoneal injection of a higher dose of streptozotocin (45 mg kg(-1)). Bosentan partially prevented stress-induced both hyperglycemia and decrease in glycogen content while it completely blocked the stress-induced decrease in insulin level in normoglycemic stressed rats. Bosentan also decreased serum glucose level without any effect on insulin secretion in mild diabetic rats and potentiated the hypoglycemic action of insulin.

Influence of medetomidine on stress-related neurohormonal and metabolic effects caused by butorphanol, fentanyl, and ketamine administration in dogs

OBJECTIVE

To examine stress-related neurohormonal and metabolic effects of butorphanol, fentanyl, and ketamine administration alone and in combination with medetomidine in dogs.

ANIMALS

10 Beagles.

PROCEDURE

5 dogs received either butorphanol (0.1 mg/kg), fentanyl (0.01 mg/kg), or ketamine (10 mg/kg) IM in a crossover design. Another 5 dogs received either medetomidine (0.02 mg/kg) and butorphanol (0.1 mg/kg), medetomidine and fentanyl (0.01 mg/kg), medetomidine and ketamine (10 mg/kg), or medetomidine and saline (0.9% NaCI) solution (0.1 mL/kg) in a similar design. Blood samples were obtained for 6 hours following the treatments. Norepinephrine, epinephrine, cortisol, glucose, insulin, and nonesterified fatty acid concentrations were determined in plasma.

RESULTS

Administration of butorphanol, fentanyl, and ketamine caused neurohormonal and metabolic changes similar to stress, including increased plasma epinephrine, cortisol, and glucose concentrations. The hyperglycemic effect of butorphanol was not significant. Ketamine caused increased norepinephrine concentration. Epinephrine concentration was correlated with glucose concentration in the butorphanol and fentanyl groups but not in the ketamine groups, suggesting an important difference between the mechanisms of the hyperglycemic effects of these drugs. Medetomidine prevented most of these effects except for hyperglycemia. Plasma glucose concentrations were lower in the combined sedation groups than in the medetomidine-saline solution group.

CONCLUSIONS AND CLINICAL RELEVANCE

Opioids or ketamine used alone may cause changes in stress-related biochemical variables in plasma. Medetomidine prevented or blunted these changes. Combined sedation provided better hormonal and metabolic stability than either component alone. We recommend using medetomidine-butorphanol or medetomidine-ketamine combinations for sedation or anesthesia of systemically healthy dogs.