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

Plasma corticosterone and plasma and pituitary ACTH concentrations were determined during feeding and after application of an acute stress at various times after food and water presentation to male rats maintained on a restricted feeding and watering schedule. Both plasma corticosterone and ACTH concentrations fell after the presentation of food and water, and this fall was accompanied by increased levels of ACTH in the pituitary gland. In addition, a rise in plasma levels of ACTH was inhibited in response to an acute stress applied at 0--5 min after presentation of food and water, but ACTH synthesis was not. This inhibition of ACTH and corticosterone secretion in response to stress was transient and dissipated as a relatively linear function of the interval between food presentation and application of the stress. The results suggest that this feeding-induced, corticosteroid-independent inhibition of pituitary-adrenal activity involves active inhibitory mechanisms operating initially on ACTH secretory processes of the pituitary and later on the synthesis of ACTH or on the secretion of hypothalamic corticotropin-releasing factor.
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PMID:Inhibition of the pituitary-adrenal response to stress during deprivation-induced feeding. 22 27

Colisa fasciatus, a fresh water teleost, when exposed for 90 hrs to a sublethal concentration of 195 p.p.m. (0.87 of the 96 hrs LC50 value) cobalt elicited leucopenia due to reduction in the number of circulating small lymphocytes. The treatment also caused decline in blood clotting time with a concomitant increase in the abundance of circulating thrombocytes. No differences in total erythrocyte count, haematocrit, erythrocyte sedimentation rate, and haemoglobin values were found between the control and treated fish. The hepatosomatic index of fish increased significantly after exposure to cobalt. Results are discussed in terms of fish's reaction to acute stress.
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PMID:Haematological anomalies in a fresh water teleost, Colisa fasciatus, on acute exposure to cobalt. 43 10

A case of psychogenic polydipsia is presented that showed psychic decompensation and compulsive drinking under the acute stress of an imminent operation for ovarian cyst. Without any indication of an underlying organic disease process the patient developed acute water intoxication due to the uncontrolled intake of water from the tap, this caused hyponatremia, brain edema, coma and status epilepticus. The physiology of water intoxication is reviewed in relation to this case, which is also remarkable for the acute onset and the shortness of the polydipsic state.
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PMID:[Water intoxication and brain edema in psychogenic polydipsia (author's transl)]. 45 41

Glycogen is an essential substrate during myocardial anoxia. Since porpranolol may maintain myocardial glycogen levels after acute stress by blockade of catecholamine-induced glycogenolysis, we evaluated the effect of propranolol treatment in the isolated perfused isovolumic paced rat heart. Forty-one rats were studied after 10 min of ice-water immersion: half were pretreated with propranolol, 20 mg/kg/day x3, and half with saline. Glycogen content of unperfused propranolol-treated hearts exceeded controls by 46% (146 +/- 9 vs. 100 +/- 4 mumoles/g dry wt, p less than 0.02), and this difference persisted during aerobic perfusion. Propranolol did not affect adenine nucleotide concentration or left ventricular hemodynamics. Following 5 min of anoxic perfusion, propranolol hearts showed improved ventricular performance concomitant with enhanced glycogenolytic flux and lactate production. Propranolol augmented high energy phosphate production (ATP/AMP = 5.19 +/- 0.42 vs. 3.39 +/- 0.42, p less than 0.02) and increased coronary flow (22.1 +/- 1.6 vs. 16.6 +/- 1.4 ml/min, p less than 0.02) during anoxia. Thus, propranolol supported glycogen stores following acute stresses, enhanced glycogenolytic energy production, increased coronary flow, and improved ventricular function during subsequent anoxia.
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PMID:Protective role of increased myocardial glycogen stores induced by propranolol. 121 34

Tumor necrosis factor (TNF), which was originally identified as a tumoricidal factor, is now regarded as one of the main regulators of inflammation and various immune systems. Thus it has been considered to be mobilized in case of emergency. However, we assume that TNF and the cytokine network driven by the monokine also function under normal condition for homeostasis of the animal body which is exposed to various kinds of physiological stress. To test this possibility, we exposed C3H/He mice for up to 3 days to five types of acute stress: food deprivation, drinking water deprivation, sleep deprivation, swimming, and physical restraint. After release from the stress, the level of priming for systemic production of TNF was examined using OK-432 (a streptococcal preparation) as a trigger. Priming of TNF production was not observed immediately after 2-day exposure to most of the stressors. Sleep deprivation alone tended to induce a primed state especially when the stress period was lengthened to 3 days. On the other hand, by keeping mice in a normal condition for a 2-day restorative interval after 2-day exposure to the stressors, systemic production of TNF was consistently primed for all the stress examined. The time course of the priming effect was examined in detail for water-deprivation stress. The effect was detected as early as 3 hours after release from stress, was sustained for 2 days, and returned to the basal level by 4 days after the release. Based on these results, we discussed the role of the TNF-driven cytokine circuit in adaptation to stress.
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PMID:Activation of the systemic production of tumor necrosis factor after exposure to acute stress. 142 Oct 11

The effect of hypoglycemic stress on the changes in water and electrolyte metabolism induced by head-down tilting (HDT) was studied. Six healthy men were subjected to postural changes (30 min standing, 2 h HDT, 1 h standing), with or without the intravenous administration of insulin at the beginning of HDT. When insulin was not given, antidiuretic hormone (ADH), cortisol, plasma renin activity (PRA), aldosterone, and catecholamine levels were decreased and atrial natriuretic polypeptide (ANP) levels increased during HDT. These changes were associated with 2.5- and 1.5-fold increases in urine flow and sodium excretion, respectively, when compared with the amounts before HDT. On the other hand, insulin-induced hypoglycemia during HDT produced increases in ADH, cortisol, PRA, aldosterone, and catecholamine levels. At the same time, an exaggerated ANP response by HDT was observed. These hormonal changes were associated with an abolishment of the increases in urine flow and sodium excretion. It is suggested that acute stress modifies the changes in fluid and electrolyte metabolism induced by HDT.
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PMID:Modification of water and electrolyte metabolism during head-down tilting by hypoglycemia in men. 147 52

The low doses of neuroleptics restored the ability of 1-DOPA treated rats to escape behaviour from acute stress situation (in the extrapolation escape test). Non-antipsychotic benzamides and phenothiazine, antidepressants and benzodiazepine tranquilizers were inactive. On the whole, the effectiveness of neuroleptics was in accordance with clinical data. The loss of ability to escape in 1-DOPA treated rats was accompanied by stereotypes hyperlocomotion in the water. Various psychotropic drugs decreased only hyperactivity without the influence on escape behaviour. Both forms of behavioral pathology were prevented by central aromatic acid decarboxylase inhibitor. However, the loss of ability to escape behavior only is selective and sensitive to neuroleptics action.
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PMID:[THe selective effect of neuroleptics on a dopamine-dependent behavioral disorder in rats in the extrapolation escape test]. 198 79

The purpose of this study was to determine if the state of physical training influences sympathetic neural activation during acute stress in humans. We recorded muscle sympathetic nerve activity (microneurography of the peroneal nerve), arterial blood pressure, and heart rate in 12 highly trained, endurance athletes (25 +/- 1 years, mean +/- SEM) and 12 untrained subjects (27 +/- 1 years) before (supine rest control) and during: 1) lower body negative pressure at -5, -10, -15, and -20 mm Hg (orthostatic stress); 2) isometric handgrip at 30% of maximum (exercise stress); and 3) hand immersion in ice water, that is, the cold pressor test (thermal stress). Body weight was not different in the two groups, but the athletes had a lower body fat content (8.9 +/- 1.3% versus 16.1 +/- 2.0%, p less than 0.05). During supine rest, muscle sympathetic nerve burst frequency (24 +/- 3 versus 24 +/- 2 bursts/min, athletes versus untrained subjects) and burst incidence (36 +/- 3 versus 44 +/- 4 bursts/100 heart beats) and arterial blood pressure were not different in the two groups, but heart rate was lower in the athletes (54 +/- 2 versus 67 +/- 3 beats/min, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Sympathetic neural adjustments to stress in physically trained and untrained humans. 198 81

Fischer-344 rat pups were injected with either 10 mg/kg delta 9-tetrahydrocannabinol (THC) or vehicle on postnatal days 4,6 and 8. Pups were then allowed to mature. On day 129 of age rats were exposed to a stress paradigm which consisted of inescapable electric foot-shock administered at 1 mA for 15 sec daily for 8 days. Analgesia induced by foot-shock was measured by tail withdrawal from 55 degree C water. On the 9th day rats were exposed to the shock environment only. Fifteen minutes following measurement of tail withdrawal, animals were sacrificed. Plasma corticosterone and prolactin were measured. Levels of norepinephrine, dopamine and 5-hydroxytryptamine and metabolites were determined in frontal cortex, hippocampus and hypothalamus. Neonatal exposure to THC produced an increase in baseline tail withdrawal latency. No effect of THC exposure was seen on acute stress-induced analgesia. Rats exposed to THC required a greater number of conditioning trials to develop conditioned analgesia than animals treated neonatally with vehicle. The conditioned stress increased plasma corticosterone without affecting prolactin. Stress increased hypothalamic 5HT and 5HIAA while decreasing 5HT turnover in this area. Dopamine and DOPAC levels in the hypothalamus and frontal cortex were increased by stress; dopamine turnover in the frontal cortex was elevated by stress. Neonatal THC and stress elevated norepinephrine above control levels in the hypothalamus, while increasing 5HT in the hippocampus and frontal cortex. The stress-induced increase in DOPAC in the frontal cortex was decreased by THC exposure. These data suggest that long-term neurochemical changes may occur with neonatal administration of THC.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Neonatal administration of delta-9-tetrahydrocannabinol (THC) alters the neurochemical response to stress in the adult Fischer-344 rat. 244 11

The triathlon is an endurance contest in which contestants must compete in 3 consecutive events, usually swimming, cycling and running. Success in a triathlon depends upon the ability of the triathlete to perform each of the sequential events at optimal pace without creating fatigue that will hinder performance in the next event. The successful triathlete must, therefore, have highly developed oxygen transport and utilisation systems as well as the ability to efficiently produce a high energy output for prolonged periods without creating metabolic acidosis. Accordingly, mean VO2max values for groups of triathletes during treadmill running have been reported to range from 52.4 to 72 ml/kg/min in men; 58.7 to 65.9 ml/kg/min in women. VO2max values during cycle ergometry were 3 to 6% less than treadmill running values; tethered swimming maximums 13 to 18% less. Predictable and well-known adaptations occur in the cardiovascular systems of triathletes. Structural adaptations of the heart that have been documented in triathletes include increased left ventricular cavity size or wall thickness, or both. Morphological characteristics of the triathlete's heart appear to be unrelated to success in triathlon races. Following the acute stress of triathlon competition, alterations in both systolic and diastolic function have been observed. Heart muscle fatigue is the most likely reason for these changes, since there is a rapid return to normal with rest. Like the cardiovascular system, the musculoskeletal system responds to triathlon training. Peripheral adaptations occur that lead to increased muscle respiratory capacity and to modifications in substrate utilisation. The musculoskeletal system is the site of most injuries to triathletes, and non-traumatic overuse injuries account for 80 to 85% of the musculoskeletal injuries. Maintenance of fluid and electrolyte balance is of primary importance for the triathlete both in day-to-day training and during races. Water may be an adequate replacement fluid for short distance triathlons, but some combination of carbohydrate, electrolyte and fluid replacement is necessary for longer races. Although the physiological bases for success in a triathlon are not well understood at present, the ability to maintain minimal alterations in the homeostasis of cardiovascular, haemodynamic, thermal, metabolic, and musculoskeletal functions are of obvious importance.
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PMID:Applied physiology of a triathlon. 269 16


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