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Query: UMLS:C0848237 (acute stress)
 4,619 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The cortisol stress response to capture was investigated in two species of fish (Perca flavescens and Esox lucius) from sites polluted by high levels of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and mercury, and from reference sites in the St. Lawrence river system. Fish from the reference sites exhibited the normal elevation of serum cortisol in response to the acute stress of capture and had large pituitary corticotropes. In contrast, fish from the most polluted sites were unable to increase their serum cortisol in response to the acute stress of capture and their pituitary corticotropes were atrophied. These results suggest that a life-long exposure to chemical pollutants may lead to an exhaustion of the cortisol-producing endocrine system, possibly as a result of prolonged hyperactivity of the system.
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PMID:Impaired cortisol stress response in fish from environments polluted by PAHs, PCBs, and mercury. 161 12

Experiments were conducted on rats to study the dynamics of changes of the heart contractile function (CF) and some indices of myocardial energy metabolism during adaptation to moderate continuous 15-day stress. After 24 hours of stress a complex of shifts typical of an acute stress syndrome (mobilization of CF, reduction of the content of glycogen and creatine phosphate, increase of phosphorylase activity) was recorded. After 5 days of stress the absolute CF value reduced, particularly at rest (doubled), as a consequence of which the relative values of the maximally developing CF on the 5th second of an isometric load induced by compression of the aorta were 1.5 times those in the controls. The content of glycogen and creatine phosphate and the activity of phosphorylase were reduced by 25-30%. After 15 days the CF and the values of myocardial energy metabolism were normalized. Exclusion of the vagal tonus by atropine on the 5th day of stress showed that the low level of CF and reduced phosphorylase activity are not consequent upon heart exhaustion but are regulatory mechanisms.
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PMID:[Contractile function and some parameters of energy metabolism of the myocardium in the process of adaptation to the effect of moderate continuous stress]. 188 2

Measurements were sought for assessment of stress during investigations of welfare in intensively housed poultry. Immobilization was used as a stressor in experiments involving 64 cockerels of various ages. Two parameters were found to be related to acute stress: plasma triiodothyronine (T3) concentration, which fell markedly, and plasma corticosterone concentration, which rose considerably, in all birds during severe stress. Concurrently, plasma thyroxine (T4) concentration also fell in most, but not all, birds. Thyrotrophin releasing hormone (TRH) injected intravenously after immobilization caused increases in T3 and T4 levels, suggesting that the fall in T3 and T4 during acute stress was not caused by exhaustion of hormone production by the thyroid gland but rather by inhibition of release of TRH at the hypothalamic level.
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PMID:Stress by immobilization, with food and water deprivation, causes changes in plasma concentration of triiodothyronine, thyroxine and corticosterone in poultry. 715 95

The General Adaptation Syndrome is characterized by three stages: Alarm Reaction - Adaptation - Exhaustion. Results of animal experiments and clinical observations indicate that both central nervous and peripheral systemic reactions to acute stress - e.g. noise - can be accentuated by magnesium deficiency and reduced by mild hypermagnesemia, respectively. Concerning long term suboptimal magnesium supply, experimental data indicate that a stage of adaptation might be achieved during a certain period of time, preceded and followed by stages of markedly decreased resistance.U
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PMID:Stress and magnesium. 730 67

We tested the hypothesis that endurance training is associated with altered basal levels of muscle sympathetic nerve activity (MSNA) and responses to acute stress in healthy older adults. MSNA (peroneal microneurography) and plasma norepinephrine (NE) concentrations were measured during supine rest, a cold pressor test, and isometric handgrip (40% maximal voluntary force to exhaustion) in 16 older masters endurance athletes [10 men, 6 women; 66 +/- 1 (SE) yr] and 15 healthy normotensive untrained control subjects (9 men, 6 women; 65 +/- 1 yr). The athletes had higher levels of estimated daily energy expenditure and maximal oxygen uptake and lower levels of resting heart rate and body fat than the control subjects (all P < 0.05). MSNA during supine rest was elevated in the athletes whether expressed as burst frequency (43 +/- 2 vs. 32 +/- 3 bursts/min, respectively; P < 0.05) or burst incidence (75 +/- 4 vs. 52 +/- 5 bursts/100 heartbeats, respectively; P < 0.01). These whole group differences were due primarily to markedly higher levels of MSNA in the athletic vs. untrained women (48 +/- 4 vs. 25 +/- 3 bursts/min, 82 +/- 3 vs. 38 +/- 3 bursts/100 heartbeats, respectively, P < 0.001). In contrast, basal plasma NE concentrations were not significantly different in the athletes vs. control subjects. The MSNA and plasma NE responses to acute stress tended to be greater in the athletes. These findings indicate that vigorous regular aerobic exercise is associated with an elevated level of MSNA at rest and a tendency for an enhanced response to acute stress in healthy normotensive older humans.
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PMID:Endurance exercise training is associated with elevated basal sympathetic nerve activity in healthy older humans. 783 41

It has been proposed that enkephalins play a role in stress phenomena. However, little is known concerning the effect of stress on the enzymes that may control the enkephalinergic activity. In the present paper we report the changes, after acute and chronic swimming-to-exhaustion stressor, of Tyr-aminopeptidase (which cleave the Tyr-Gly amide-bond) in discrete areas of the rat brain. After acute stress, only significant decreases in the striatum were observed. After chronic application, decreases in the striatum and increases in the hypothalamus and the medulla were seen.
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PMID:Effect of swimming-to-exhaustion stress on the Tyr-aminopeptidase activity in different brain areas of the rat. 808

The effects of a 7-day period of daily physical stress (chasing until exhaustion) on the beta-adrenergic response of the rainbow trout (Oncorhynchus mykiss) red blood cell (rbc) were examined in vitro. Physical stress was associated with pronounced increases in the circulating levels of the catecholamine hormones (adrenaline and noradrenaline) measured on days 1, 3 and 7 of the stress regime. After 7 days, the numbers of high-affinity cell surface beta-adrenoceptors were reduced in the physically stressed fish when measured in vitro under conditions of normoxia (20 % reduction) or hypoxia (30 % reduction). Under hypoxic conditions, the binding affinity of the rbc beta-adrenoceptor was significantly higher in the stressed fish. Although the stressed fish had fewer beta-adrenoceptors, rbc adrenergic responsiveness was enhanced after 7 days of physical stress as determined from dose-response curves relating noradrenaline concentration to water and Na+ accumulation (indices of rbc adrenergic Na+/H+ exchange activity). The EC50 values (concentrations yielding half-maximal responses) for noradrenaline were lowered significantly by 1.7- to 3.9-fold in the blood from physically stressed fish. The enhanced adrenergic responsiveness of the rbcs appeared to be unrelated to changes in the initial steps of the beta-adrenergic signal transduction pathway leading to cyclic AMP production because physical stress was without effect on the magnitude or the dose-dependency of rbc cyclic AMP accumulation. To determine whether post-cyclic-AMP events were affected by physical stress, water and Na+ accumulation were measured in rbcs that had been incubated with the permeable cyclic AMP analogue 8-bromo cyclic AMP. The EC50 values for 8-bromo cyclic AMP were lowered by 1.6- to 1.7-fold in the blood from stressed fish. These experiments demonstrate that repeated physical stress significantly enhances the adrenergic responsiveness of the rainbow trout rbc, presumably by modifying the sensitivity of the Na+/H+ exchanger (or the steps immediately preceding exchanger activation) to cyclic AMP. The results are discussed with respect to the interrelationships between chronic and acute stress responses in fish.
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PMID:The effects of repeated physical stress on the b-adrenergic response of the rainbow trout red blood cell 931 46

Acute mental and physical stress lead to a marked lymphocytosis, with circulating natural killer cell numbers showing the most prominent increase. Many studies have linked these acute stress effects on lymphocytes with an increase in catecholamine levels. However, the molecular mechanisms which mediate this redistribution of lymphocytes from lymphocyte reservoirs into the circulation remain unknown. We hypothesized that this form of lymphocytosis was in part due to shedding of cell adhesion molecules from the cell surface and a subsequent detachment of lymphocytes adhering to the vascular endothelium in lymphocyte reservoirs. In this study, healthy human volunteers (n = 12) were exercised on a treadmill until exhaustion. The circulating levels of the soluble cell adhesion molecules ICAM-1 and E-Selectin were determined by ELISA. The subjects were then randomly assigned to treatment with either propranolol or metoprolol and repeated the exercise protocol after 1 week of treatment. Prior to drug treatment, soluble ICAM-1 levels rose from 258 +/- 19 to 321 +/- 28 ng/ml following exercise and returned to approximate baseline levels of 263 +/- 22 ng/ml after 1 h of rest. This highly significant effect of exercise on circulating ICAM-1 levels (p < .005) was mitigated after treatment with the beta-adrenergic antagonists. Soluble E-Selectin levels were not significantly affected by exercise. These results suggest that dynamic exercise leads to shedding of the cell adhesion molecule ICAM-1 via adrenergic mechanisms. We believe that these findings will contribute to the understanding of how physical and mental stress modulate lymphocyte migration and adhesion.
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PMID:Dynamic exercise leads to an increase in circulating ICAM-1: further evidence for adrenergic modulation of cell adhesion. 951 20

This review article integrates empirical findings from various scientific disciplines into a proposed psychoneuroimmunological (PNI) model of the acute coronary syndrome (ACS). Our starting point is an existing, mild, atherosclerotic plaque and a dysfunctional endothelium. The ACS is triggered by three stages. (1) Plaque instability: Pro-inflammatory cytokines (IL-1, IL-6, TNF-alpha) and chemoattractants (MCP-1, IL-8) induce leukocyte chemoattraction to the endothelium, and together with other triggers such as the CD40L-CD40 co-stimulation system activate plaque monocytes (macrophages). The macrophages then produce matrix metalloproteinases that disintegrate extra-cellular plaque matrix, causing coronary plaque instability. Acute stress, hostility, depression and vital exhaustion (VE) have been associated with elevated pro-inflammatory cytokines and leukocyte levels and their recruitment. (2) Extra-plaque factors promoting rupture: Neuro-endocrinological factors (norepinephrine) and cytokines induce vasoconstriction and elevated blood pressure (BP), both provoking a vulnerable plaque to rupture. Hostility/anger and acute stress can lead to vasoconstriction and elevated BP via catecholamines. (3) Superimposed thrombosis at a ruptured site: Increases in coagulation factors and reductions in anticoagulation factors (e.g. protein C) induced by inflammatory factors enhance platelet aggregation, a key stage in thrombosis. Hostility, depression and VE have been positively correlated with platelet aggregation. Thrombosis can lead to severe coronary occlusion, clinically manifested as an ACS. Thus, PNI processes might, at least in part, contribute to the pathogenesis of the ACS. This chain of events may endure due to lack of neuroendocrine-to-immune negative feedback stemming from cortisol resistance. This model has implications for the use of psychological interventions in ACS patients.
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PMID:Molecular and cellular interface between behavior and acute coronary syndromes. 1223 62

The associations between vital exhaustion (long-term stress), temperament, and cardiac reactivity were studied during an experimentally induced stress in a sample of 76 healthy subjects. Vital exhaustion was assessed with the Maastricht Questionnaire(MQ), and temperament with Cloninger's Temperament and Character Inventory (TCI). Cardiac reactivity was measured in terms of heart rate, respiratory sinus arrhythmia, and pre-ejection period. They were continuously measured during three stressors, i.e. mental arithmetic, reaction time, and giving speech. Results showed that vital exhaustion (long-term stress) was first of all associated with parasympathetic withdrawal. In addition, among exhausted persons the initial parasympathetic tone had no effect on task-induced parasympathetic reactivity, whereas in non-exhausted subjects parasympathetic reactivity was greatest when initial parasympathetic tone was high. Vital exhaustion interacted with temperament and gender: exhausted, persistent women expressed the highest level of physiological stress reactivity. Findings suggest that background stress may diminish one's capacity to cope with acute stress.
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PMID:Vital exhaustion, temperament, and cardiac reactivity in task-induced stress. 1470 35


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