Stress adaptation disorders play a role in rat gestational diabetes with oxidative stress and glucose transporter-4 expression

Stress adaptation disorder exists in gestational diabetes mellitus (GDM) women, this study was to investigate the impact of stress adaptation disorder on glucose disposal and skeletal muscle glucose transporter4 (GLUT4) expression in GDM rat model. Rats were assigned randomly to Normal control (NC) group and GDM group. We analyzed the levels of corticosterone, epinephrine (E), norepinephrine (NE), malondialdehyde (MDA) and superoxide dismutase (SOD), interleukin-6 (IL-6) and expression of GLUT4 were also detected. Homeostasis model assessment (HOMA-IR) was used to evaluate insulin resistance. Compared with NC group, E, NE and Corticosterone were increased significantly, SOD and MDA were higher and GLUT4 expression was significantly lower in GDM rats. Corticosterone was positively related to MDA, MDA was positively and SOD was negatively related to HOMA-IR in both groups, IL-6 showed significant positive correlations with HOMA-IR. NE and Corticosterone were negative related to GLUT4 in GDM group. Stress hormones (E, NE and Corticosterone), MDA and IL-6 were the risk factors of GDM, SOD was the protective factor of GDM. Changes of stress hormones indicate that stress adaptation disorder exists in GDM rats. Stress adaptation disorder increase oxidative stress injury and inflammation, decrease GLUT4 and lead to incline of glucose uptake, result in hyperglycemia. Gaining an insight into correlations of these changes may be beneficial to maternal and child health and is important for the prevention of glycemia-related diseases.

[THE ROLE OF THE ENDOGENOUS CANNABINOID SYSTEM IN THE FORMATION OF THE GENERAL ADAPTATION SYNDROME]

Nonopioid stress-induced analgesia is the consequence of activation of CB1 receptors by the increased level of 2-arachidonoyl glycerol, anandamide in the periaqueductal gray matter in the midbrain. The activation of cannabinoid CB1 receptors inhibits stress-induced ulcerogenesis due to the strengthening of the antioxidant defense of the gastric mucosa. CB1 receptor antagonists promote an increase in ACTH and corticosterone concentrations in the blood of intact animals, the knockout of the gene encoding the CB1 receptor exhibits the same effect. Antagonists of CB1 receptors enhance the stressor elevation of ACTH and corticosterone levels in the blood of experimental animals. It was found an increase in stress-induced elevation of corticosterone and ACTH levels in the blood of mice with a knockout of the gene encoding the CB1 receptor. An increase in the endogenous anandamide level or disturbance of the reuptake of endogenous cannabi-noids after application of pharmacological agents promotes reducing corticosterone level in stressed animals. Consequently, endogenous cannabinoids inhibit basal and suppress stress-induced activity of the hypothalamic-pituitary-adrenal axis. The indicated regulation is carried out on the level of the hypothalamus, pituitary and adrenal cortex. Stimulation of central cannabinoid receptors leads to an activation of the sympathetic system. The activation of peripheral CB1 receptors leads to inhibition of norepinephrine release from sympathetic terminals and epinephrine release from the adrenal glands. The endogenous CB1 receptor agonists play an anxiolytic role and prevent the occurrence of pathological anxiety.

HANS SELYE AND THE STRESS RESPONSE: FROM "THE FIRST MEDIATOR" TO THE IDENTIFICATION OF THE HYPOTHALAMIC CORTICOTROPIN-RELEASING FACTOR

Selye pioneered the stress concept that is ingrained in the vocabulary of daily life. This was originally build on experimental observations that divers noxious agents can trigger a similar triad of endocrine (adrenal enlargement), immune (involution of thymus) and gut (gastric erosion formation) responses as reported in a letter to Nature in 1936. Subsequently, he articulated the underlying mechanisms and hypothesized the existence of a "first mediator" in the hypothalamus able to orchestrate this bodily changes. However he took two generations to identify this mediator. The Nobel Laureate, Roger Guillemin, a former Selye's PhD student, demonstrated in 1955 the existence of a hypothalamic factor that elicited adrenocorticotropic hormone release from the rat pituitary and named it corticotropin releasing factor (CRF). In 1981, Wylie Vale, a former Guillemin's Ph Student, characterized CRF as 41 amino acid and cloned the CRF1 and CRF2 receptors. This paves the way to experimental studies establishing that the activation of the CRF signaling pathways in the brain plays a key role in mediating the stress-related endocrine, behavioral, autonomic and visceral responses. The unraveling of the biochemical coding of stress is rooted in Selye legacy continues to have increasing impact on the scientific community.

Catecholamines and stress

A brief survey is offering of debates on two long-standing questions in stress studies and theories: 1) question of stress nonspecificity (i.e. homo- or heterogeneity in stress responses), and 2) what is the functional role of central catecholamines in stress mechanisms, especially in stress signal-transduction and in the realization of stress responses.

[Role of hormonal regulation and stress in the interaction of sleep and biorhythms in aging]

The present work describes bibliographic analysis of ontogenetic changes in hormonal regulation of sleep and circadian biorhythms. It is suggested that two-stage, age-related dynamics of such changes may be related to differential occurrence registered by us earlier, of maxima of morbidity and mortality caused by a number of disorders, in middle-age and in senile period. It is proposed to concentrate future efforts on elaboration of mathematical models of ontogenetic regulation, on the basis of systems biomedicine.

One-year monitoring of core biomarker and digestive enzyme responses in transplanted zebra mussels (Dreissena polymorpha)

A 12-month active biomonitoring study was performed in 2008-2009 on the Vesle river basin (Champagne-Ardenne, France) using the freshwater mussel Dreissena polymorpha as a sentinel species; allochthonous mussels originating from a reference site (Commercy) were exposed at four sites (Bouy, Sept-Saulx, Fismes, Ardre) within the Vesle river basin. Selected core biomarkers (acetylcholinesterase (AChE) activity, glutathione-S transferase (GST) activity, metallothionein concentration), along with digestive enzyme activities (amylase, endocellulase) and energy reserve concentrations (glycogen, lipids), were monitored throughout the study in exposed mussels. At the Fismes and Ardre sites (downstream basin), metallic and organic contamination levels were low but still high enough to elicit AChE and GST activity induction in exposed mussels (chemical stress); besides, chemical pollutants had no apparent deleterious effects on mussel condition. At the Bouy and Sept-Saulx sites (upstream basin), mussels obviously suffered from adverse food conditions which seriously impaired individual physiological state and survival (nutritional stress); food scarcity had however no apparent effects on core biomarker responses. Digestive enzyme activities responded to both chemical and nutritional stresses, the increase in energy outputs (general adaptation syndrome-downstream sites) or the decrease in energy inputs (food scarcity-upstream sites) leading to mid- or long-term induction of digestive carbohydrase activities in exposed mussels (energy optimizing strategy). Complex regulation patterns of these activities require nevertheless the use of a multi-marker approach to allow data interpretation. Besides, their sensitivity to natural confounding environmental factors remains to be precised.

Stress reactivity and corticolimbic response to emotional faces in adolescents

OBJECTIVE

Adolescence is a critical period in the development of lifelong patterns of responding to stress. Understanding underpinnings of variations in stress reactivity in adolescents is important, as adolescents with altered stress reactivity are vulnerable to negative risk-taking behaviors including substance use, and have increased lifelong risk for psychopathology. Although both endocrinological and corticolimbic neural system mechanisms are implicated in the development of stress reactivity patterns, the roles of these systems and interactions between the systems in reactivity to social stimuli in adolescents are not clear. We investigated the relationship between cortisol response to a laboratory-based social stressor and regional brain responses to emotional face stimuli in adolescents.

METHOD

Changes in cortisol levels following the Trier Social Stress Test-Child version (TSST-C) were measured in 23 disadvantaged and chronically stressed adolescents who also participated in functional magnetic resonance imaging during processing of emotional faces and structural magnetic resonance imaging. The relationships between changes in cortisol following the TSST-C with regional brain activation during face processing, as well as with regional brain morphology, were assessed.

RESULTS

Cortisol change on the TSST-C showed a significant inverse relationship with left hippocampus response to fearful faces (p < .05, corrected); significant associations with volume were not observed.

CONCLUSIONS

Increased cortisol response to the Trier social stressor was associated with diminished response of the left hippocampus to faces depicting fear. This suggests that HPA-corticolimbic system mechanisms may underlie vulnerability to maladaptive responses to stress in adolescents that may contribute to development of stress-related disorders.

Heat shock proteins (chaperones) in fish and shellfish and their potential role in relation to fish health: a review

Heat shock proteins (HSPs), also known as stress proteins and extrinsic chaperones, are a suite of highly conserved proteins of varying molecular weight (c. 16-100 kDa) produced in all cellular organisms when they are exposed to stress. They develop following up-regulation of specific genes, whose transcription is mediated by the interaction of heat shock factors with heat shock elements in gene promoter regions. HSPs function as helper molecules or chaperones for all protein and lipid metabolic activities of the cell, and it is now recognized that the up-regulation in response to stress is universal to all cells and not restricted to heat stress. Thus, other stressors such as anoxia, ischaemia, toxins, protein degradation, hypoxia, acidosis and microbial damage will also lead to their up-regulation. They play a fundamental role in the regulation of normal protein synthesis within the cell. HSP families, such as HSP90 and HSP70, are critical to the folding and assembly of other cellular proteins and are also involved in regulation of kinetic partitioning between folding, translocation and aggregation within the cell. HSPs also have a wider role in relation to the function of the immune system, apoptosis and various facets of the inflammatory process. In aquatic animals, they have been shown to play an important role in health, in relation to the host response to environmental pollutants, to food toxins and in particular in the development of inflammation and the specific and non-specific immune responses to bacterial and viral infections in both finfish and shrimp. With the recent development of non-traumatic methods for enhancing HSP levels in fish and shrimp populations via heat, via provision of exogenous HSPs or by oral or water administration of HSP stimulants, they have also, in addition to the health effects, been demonstrated to be valuable in contributing to reducing trauma and physical stress in relation to husbandry events such as transportation and vaccination.

[Stress-protective activity of the CH3CO-Lys-Lys-Arg-Arg-NH2 synthetic peptide (protektin)]

The CH3CO-Lys-Lys-Arg-Arg-NH2 peptide (the author has named it protectin) was synthesized, and its activity was studied during different stress actions. Protectin was found to normalize the content of corticosterone and adrenalin in adrenal glands and blood after its intranasal administration to rats one day before a cold or heat shock, or hypobaric hypoxia at doses of 1-10 microg/animal and after its intravenous administration just after acute hemorrhage at doses of 0.5-2 microg/animal. The intranasal administration of protectin at doses of 1-10 microg/rat one day before the heat or cold shock was also shown to prevent a change in the content of free histamine and the activity of diamine oxidase in myocardium, which was induced by the dramatic change in the activity of the enzyme after the temperature actions.

[Hemodynamics, the autonomic nervous system and water metabolism as criteria for developing the general adaptation syndrome in pregnant women]

By taking into account the fact that the autonomic nervous and cardiovascular systems (ANS and CVS) are the major links of development of the general adaptation syndrome in pregnancy, which are affected by all the processes involved in the development of the syndrome, the author analyzed the state of these systems in healthy non-pregnant and pregnant women (HNPW and HPW) and in pregnant women with gestosis. HNPW were found to have already a prerequisite for impairing pregnancy adaptive processes as ANS and CVS dysfunction. In HPW, these impairments were more pronounced. In the pregnant women, impaired adaptive processes manifested themselves as excess sympathicotonia in 72% and parasympathicotonia in 23% of cases despite the treatment performed, which was accompanied by hypokinetic hemodynamics in 53 and 50%, respectively. In hyper- and eukinetic hemodynamics, there were no physiologically required decreases in total peripheral vascular resistance while in hypokinetic hemodynamics, there was its pathological increase. Such disorders enhance the significance of abdominal compartment syndrome, aortocaval compression, ischemia-reperfusion, hydrodynamic and membranogenic (capillary leakage) factors of impaired water metabolism, which contributes to adaptation derangement. Based on the findings, the authors have created a developmental modulation algorithm for the general adaptation syndrome by completed pregnancy and surgical delivery.

[Pregnancy in the context of general adaptation syndrome]

Based on their own findings and the data available in the literature on pregnancy including that complicated by gestosis, the authors consider these conditions in the context of Selye's general adaptation syndrome. They identify its basic links (the autonomic nervous and cardiovascular systems) the function of which is affected by all the physiological and pathophysiological processes involved in its development. There is a high likelihood of baseline impaired adaption processes in these links, which may lead to an inability to accommodate (dysadaptation) by the moment of delivery. The paper gives the current interpretation of functional disorders, called Zangemeister'a triad in 1913, from the present-day points of view of the evaluation of pregnancy as the systemic inflammatory response syndrome and, probably, adaptation disease. Based on the results of analyzing the data available in the literature, the authors indicate physiologically the basic trends in the modulation of impaired development processes of the general adaptation syndrome towards the completion of pregnancy and surgical delivery.

Neurosteroids in the context of stress: implications for depressive disorders

Animal models indicate that the neuroactive steroids 3alpha,5alpha-THP (allopregnanolone) and 3alpha,5alpha-THDOC (allotetrahydroDOC) are stress responsive, serving as homeostatic mechanisms in restoring normal GABAergic and hypothalamic-pituitary-adrenal (HPA) function following stress. While neurosteroid increases to stress are adaptive in the short term, animal models of chronic stress and depression find lower brain and plasma neurosteroid concentrations and alterations in neurosteroid responses to acute stressors. It has been suggested that disruption in this homeostatic mechanism may play a pathogenic role in some psychiatric disorders related to stress. In humans, neurosteroid depletion is consistently documented in patients with current depression and may reflect their greater chronic stress. Women with the depressive disorder, premenstrual dysphoric disorder (PMDD), have greater daily stress and a greater rate of traumatic stress. While results on baseline concentrations of neuroactive steroids in PMDD are mixed, PMDD women have diminished functional sensitivity of GABA(A) receptors and our laboratory has found blunted allopregnanolone responses to mental stress relative to non-PMDD controls. Similarly, euthymic women with histories of clinical depression, which may represent a large proportion of PMDD women, show more severe dysphoric mood symptoms and blunted allopregnanolone responses to stress versus never-depressed women. It is suggested that failure to mount an appropriate allopregnanolone response to stress may reflect the price of repeated biological adaptations to the increased life stress that is well documented in depressive disorders and altered allopregnanolone stress responsivity may also contribute to the dysregulation seen in HPA axis function in depression.

[Dependence of the pharmacokinetics of captopril on the type of adaptation reactions in the organism]

The dependence of the pharmacokinetic profiles (PhP) of captopril in the phase of adaptation reactions in the organism has been studied within the framework of randomized, comparative, double cross research of bioeqivalency of captopril (Aspharma Co, Anzhero-Sudzhensk) and capoten (Bristol Myers Squibb Co.; official Russian producer, Akrikhin KhimFarmKombinat). It is established that the maximum bioaccessibility and high concentration of captopril in the blood plasma is determined on the background of physiologically optimum reactions of training and in the zone of quiet activation. These characteristics decrease during the reactions of general adaptation syndrome according to the type of increased activation and reactivation.

[The inhibitor of free radical processes decrease of protein biosynthesis in gun short wound tissues and weaken development of the general adaptation syndrome]

The dynamics of total protein biosynthesis and procollagen biosynthesis in skeletal muscle of injury tissues with the antioxidant BHT (dibunol) treatment and with common healing were studied. The obtained date indicate that the AO treatment reduce the rate of biosynthesis both the total proteins and procollagen at the 3th day of healing. Dibunol also considerably reduce the protein biosynthesis in adrenals and brake of corticosteroids biogenesis as measured by ESR-signals intensity of reduced adrenodoxine. AO treatment also reduce the protein biosynthesis in thymus, spleen and bone marrow. The lowering of functional activity of endocrine and immune systems indicate that the AO significantly inhibit the systemic reactions of organism induced by acute wound affect. It was suggested that as "primary mediator" of stress-reaction may be considered lipoperoxide radicals and decay products of lipohydroperoide.

[Stress in the etiology of radiation injury. Role of regulatory mechanisms]

Radiation damage as stress is regarded in the review. The place of lipid peroxidation in the starting of stress reaction and the possibility of the application of antioxidants and thymus preparations as factors which lower the hardness of radiation damage are considered.

Stress-induced arrhythmic disease of the heart--Part I

This review deals with the following principal concepts: (1) Heart injuries in single severe stress episodes manifested primarily in disturbances of membrane lipid bilayer, sarcolemmal Na, K-pump, and sarcoplasmic Ca-pump with concurrent limited disturbances of the heart energy supply, namely, of the creatine kinase and glycolysis systems. These disturbances cause small focal myocardial lesions and reduce cardiac electrical stability: the fibrillation threshold falls and ectopic activity increases. In repeated stress, this damage, localized mainly in the richly innervated conduction system, accumulates to cause even more pronounced disturbances of electrical stability and severe arrhythmias. (2) Severe stress and beta-adrenergic effects on the heart regularly result in coronary vasodilation and increased coronary blood flow. However, the entire primary complex of stress-induced injuries and disturbances of the heart's electrical stability occurs despite the increased coronary blood flow. Thus, beta-adrenergic stress-induced injuries may indeed develop as primary stress damage to cardiomyocytes without any relation to ischemia. (3) The main factor determining high vulnerability or, on the contrary, resistance of the heart to stress is the state of stress-limiting systems, namely, the opioidergic, GABAergic, cholinergic, adenosinergic, and other systems. Activation of these systems by adaptation to repeated stress or other factors prevents serious injuries to the heart in severe stress. Conversely, genetically determined or acquired dysfunction of these systems predisposes to severe arrhythmias and sudden death. Thus, in stress-induced arrhythmic disease as well as in ischemic heart disease, the main pathogenetic links are outside the heart, but they differ from those observed in ischemia. (4) The clinical picture of stress-induced arrhythmic disease, that is, alterations in electrocardiogram, coronarogram, and patient responses to stress, physical loads, and tranquilizers differ, as do pathologic alterations in the heart. These differences are summarized at the end of this review.

[Indices of lipid free-radical oxidation and of antiradical protection of the brain--the neurochemical correlates of the development of the general adaptation syndrome]

The stage of rat long-term adaptation to chronic emotional-pain stress is characterized by an increase of superoxide dismutase brain activity and superoxide-scavenging blood serum activity, accumulation of fluorescent products of free-radical oxidation, reduction of phospholipids and cholesterin contents in the brain lipid extracts. In the process of prolonged adaptation to the continuing chronic emotional-pain stress three periods are singled out, each of which with a definite correlation of characteristics of vegetative functions, behaviour, intensity of free-radical oxidation and antiradical defence.

[Effect of stress, infarction and adaptation to brief exposure to stress on opioid peptide levels in the brain]

Content of beta-endorphine, Met- and Leu-encephalines was studied in various brain regions and in adrenal glands after long-term immobilization stress, after myocardial infarction and during prolonged gradual adaptation to short-term stressory affects. Acute stressory conditions, myocardial infarction or, especially distinct adaptation to short-term stressory affects were shown to cause an accumulation of opioid peptides in brain structures and in adrenal glands. This increase in opioid peptides accumulated as a tissue reserve appears to elevate the body resistance to subsequent injuring affects.

[Energy metabolism during stressful exposures (ionizing radiation), its self-regulation and correction]

Normal hormonal regulation of energy metabolism is mainly realized by glucocorticoids and insulin, their physiological antagonist. Under the effect of different extremal factors (including ionizing radiation) there arises non-specific stress, a syndrome the main component of which is the hyperfunction of glucocorticoids--the intermediate hormonal link in the stress reaction. Stimulation of hypercorticism by administering hydrocortisone to intact animals as well as its stimulation by administering this preparation to irradiated animals causes development and intensification of inhibition and uncoupling of the oxidative phosphorylation as well as disturbance in adenylic nucleotides metabolism. The administered insulin, softening the reaction of hypercorticism and changing the ratio of the hormone levels in favour of insulin, weakens essentially the stress (ray) disturbances in the energy metabolism.

[Blood lipid and blood glucose changes during single, multiple and repeated stress]

As soon as various stressors exceed specific thresholds they induce marked metabolic changes in the organism. In a number of studies these facts have been verified experimentally. In our investigations we were able to demonstrate that the pattern of stress-induced changes differs after single and multiple stress exposures and that metoblic alterations in repeated stress situations are modified by habituative and adaptative processes respectively. Stress-induced metabolic mechanisms differently develop for blood lipid fractions and blood glucose. The described mechanisms are explained according to the functions of these blood parameters during stress exposures. The differential analysis of these alterations may be important for the prevention of stress-induced metabolic disorders.

[General adaptation syndrome (Selye) in the calf. 5. Effect of increased glucocorticosteroid values on the phagocytosis activity of luekocytes, the function of RHS and the morphology of lymphatic organs]

Studies were conducted with the view to elucidating the correlations between increased glucocorticosteroid levels in the blood and the defense potential of calf organism against infectious diseases. The test animals were exposed to several substances (ACTH, cortisol, colibacteria, coliendotoxin), and even one to two days of increased 11-OHKS values were followed by marked decline in phagocytosis activity of leucocytes. In addition, RHS function was considerably reduced, after ten to thirteen days of application had elapsed, since at that point the disappearance of intravenously applied bacteria from circulating blood of test animals took place at rates which were much lower than those recorded from untreated calves. Differentiated length of stress or action (four to thirteen days) was followed by conspicuous changes in the lymphatic tissue of calf organism, with severe involution of thymus and follicular atrophy of intestine-associated lymphatic tissue having been the major findings. The results seem to suggest that rise in adrenocortical hormone level under stress may reduce potential organic defense to infection.