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

This study was performed to investigate the influence of repeated psychological stress alone or combined with high NaCl intake on the function of the sympathetic nervous system. In addition, NPY levels have been measured in brain regions of potential importance in the central regulation of stress responses (ventrolateral and dorsomedial medulla, paraventricular and arcuate nucleus of the hypothalamus, and frontal cortex). Normotensive Wistar rats received a standard diet alone or supplemented with NaCl. To accentuate differences in sodium balance, rats on the high NaCl diet (HNa) were uninephrectomized. Half the animals on each diet were subjected to chronic stress using daily sessions (1 h) of immobilization stress. After 12 days, plasma levels of neuropeptide Y (NPY), norepinephrine (NE), and epinephrine (E) were measured basally and in response to acute footshock stress. HNa intake or chronic stress alone did not significantly alter either basal or stimulated plasma levels of NPY. However, combining the treatments produced a significant interaction, increasing the NPY response to footshock by 31% compared to HNa alone (p = 0.039) and by 98% compared to stress alone (p less than 0.001). Chronic stress increased basal levels of NE and enhanced the response to subsequent acute stress: combining the treatments did not yield further increases. Plasma levels of E were not significantly affected by the treatments. In the brain, stress alone had no effect on the NPY levels in the structures studied. HNa intake induced a significant increase in NPY levels of the arcuate nucleus, and produced a significant interaction with stress in the dorsomedial medulla. In a supplementary experiment, to evaluate the role of the autonomic nervous system in plasma NPY responses, treatment with the ganglion blocker hexamethonium was shown to significantly attenuate stress-induced changes in NPY, NE, and E.
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PMID:Central and peripheral effects of repeated stress and high NaCl diet on neuropeptide Y. 135 17

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

In summary, according to the proposed model, race is viewed as a sociocultural designation that denotes differential exposure to chronic social stressors. It is proposed that black Americans are exposed to significantly more chronic social stressors than are white Americans. Many of these chronic social stressors have been associated with hypertension prevalence in epidemiological studies. Furthermore, chronic stress has been shown to augment cardiovascular reactivity to acute stress in both animals and humans, and to increase sodium retention in spontaneously hypertensive rats. Acute stress has also been demonstrated to increase sodium retention in humans. The essential element of our model is that chronic social stressors that are represented more within the black American population due to historical factors are related to an increase in sodium sensitivity and retention. This altered sodium metabolism may be further augmented by biological, behavioral, and psychological risk factors for hypertension and modulated by stress coping resources. It is hoped that this model will serve as a stimulus for further research on the biopsychosocial aspects of autonomic reactivity and hypertension in blacks.
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PMID:Autonomic reactivity and hypertension in blacks: a review and proposed model. 184 32

The effect of acute stress, with and without pain, on serum and mononuclear cell cation content was studied in 205 healthy women in their last trimester of pregnancy or during normal labour, in patients with acute medical conditions in which pain was or was not present, in acute surgical conditions, and immediately prior to elective surgery. In all subjects there was a fall in serum sodium, potassium, magnesium and calcium concentrations during stress, with an apparent shift into the intracellular space. An inverse correlation was present between the severity of pain and the fall in serum cations.
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PMID:Serum and intracellular electrolytes in patients with and without pain. 186 34

The relationships between stress and hypertension have been evaluated extensively. Acutely, stress has been shown to increase blood pressure by increasing cardiac output and the heart rate without affecting total peripheral resistance. Acute stress has been found to increase levels of catecholamines, cortisol, vasopressin, endorphins and aldosterone, which may in part explain the increase in blood pressure. However, a primary role for the activation of the sympathetic nervous system has recently been suggested in several studies. Studies in the rat are beginning to determine specific central nervous system pathways which transform stressful stimuli into signals triggering a cardiovascular response without direct cortical participation. Furthermore, acute stress reduces renal sodium excretion, which contributes to an increase in blood pressure. Several studies suggest that prolonged stress may predispose people and animals to prolonged hypertension and certain populations are at risk for the development of stress-induced hypertension. It is likely that prolonged stress-induced hypertension is the result of neurohormonal trophic factors which cause vascular hypertrophy or atherosclerosis. Because stress can affect measurement of blood pressure due to the phenomenon of 'white-coat hypertension', ambulatory blood pressure monitoring is emerging as an important feature in the evaluation of patients with hypertension. Finally, relaxation techniques are being used increasingly in the treatment of patients with hypertension.
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PMID:Stress and hypertension. 225 76

The effect of maternal strain on reactivity to acute stress was studied in F1 reciprocals produced by crossing the spontaneously hypertensive rat (SHR) with its normotensive progenitor, the Wistar-Kyoto (WKY). This F1 generation, known as the borderline hypertensive rat (BHR), is genetically predisposed to develop hypertension in response to chronic stress or high dietary sodium. Reciprocals, considered to be genetically equivalent aside from sex-linked traits, differ in strain of dam during intrauterine and preweanling development. At 17 weeks of age, reciprocal F1 males did not differ in open-field behavior (squares crossed, rearings, and defecation measured over 3 days in 15-min sessions) or in home-cage measurements of mean arterial pressure (MAP) and heart rate (HR). However, different patterns of cardiovascular reactivity were displayed to transfer and footshock. While WKY-mothered rats reacted with graded pressor responses, SHR-mothered rats responded maximally to transfer, showed no additional increase to footshock, and maintained peak responding after footshock was terminated. Such reactivity differences may mediate the impact of environmental variables on the genetic disposition to hypertension.
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PMID:Dam strain affects cardiovascular reactivity to acute stress in BHR. 232 28

The effects of dietary Na+, K+, and Cl- and of acute stress on plasma levels of Na+, K+, aldosterone, and corticosterone were evaluated in vivo in birds. The dietary effects were studied in growing White Rock chicks, whereas the larger turkey was preferred for the acute stress study. Although plasma corticosterone remained unaffected, plasma aldosterone concentration decreased with increasing levels of dietary Na+ reaching a minimum at a dietary level of 72 meq/kg. Plasma Na+ remained unchanged when dietary Na+ levels increased up to 72 meq/kg but then rose with increasing Na+ intake. Plasma K+ was slightly depressed by high levels of dietary Na+ and increased by dietary K+. Neither plasma Na+ nor circulating adrenal hormones were affected by dietary K+ or dietary Cl-. Acute stress stimulated both aldosterone and corticosterone without any effect on the levels of the plasma minerals. The results suggest that of the two main corticoids, only aldosterone responds to dietary Na+ in chicks. This is in contrast to the indiscriminate stimulation of both hormones by stress, indicating different pathways of stimulation. The results also suggest that aldosterone is involved in the regulation of plasma Na+ only at low intakes of Na+ and that dietary K+ and Cl- are not involved in the aldosterone-Na+ feedback relationship.
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PMID:Concentration of adrenocortical hormones in relation to cation homeostasis in birds. 360 85

Plasma levels of corticosterone and aldosterone were determined by radioimmunoassay in ducks consuming diets containing different concentrations of sodium and potassium. Compared with control diet birds, maintenance on a high-Na+ diet for 5 days caused a 2-fold increase in the basal plasma corticosterone concentration, while adaptation for 8 days to a low-Na+ diet resulted in a 2.6-fold increase in the basal plasma concentration of aldosterone. Both corticosterone and aldosterone basal plasma levels were greatly elevated in birds denied access to drinking water for 4 days. Adaptation to a high-Na+ diet or deprivation of water resulted in hyperosmolality and hypernatremia, while the high-K+, low-Na+/low-K+, and low-Na+ diets did not significantly alter the plasma sodium or potassium levels from the control levels. In addition, birds were stressed by semi-immobilization to determine the effects of acute stress-induced ACTH secretion on the adrenocortical response following changes in dietary sodium and potassium intake. In ducks adapted to low-Na+/low-K+, high-Na+, and low-Na+ diets, stress-induced adrenocorticotrophic hormone (ACTH) increased the aldosterone, but not the corticosterone, response to a level significantly greater than in the controls. These results demonstrate that in the duck secretion of corticosterone and aldosterone can be independently regulated. Furthermore, the endocrine changes that are induced by altered sodium and potassium intake are reflected in the adrenocortical responses to acute stress.
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PMID:Effects of chronic changes in dietary electrolytes and acute stress on plasma levels of corticosterone and aldosterone in the duck (Anas platyrhynchos). 398 30

The effect of restraint stress (RS) on the red cell sodium pump, hematocrit, plasma osmolality and plasma sodium and potassium concentrations was measured. Ten min of RS did not produce any change in the sodium pump activity. Longer lasting stress - 150 min - stimulated significantly the sodium pump activity in comparison to the control group (8.52 +/- 0.76 vs. 7.78 +/- 0.46 min-1 per 10(13) Ery; P less than 0.05; means +/- S.D.). Hematocrit rose during the stress (controls: 44.8 +/- 2.3; 10 min RS: 48.1 +/- 1.1; 150 RS: 47.0 +/- 1.9%; P less than 0.01 and P less than 0.05, respectively). The values for osmolality and plasma sodium concentration did not change. However, the plasma potassium concentration decreased significantly after 150 min of RS (4.63 +/- +/- 0.74 vs. 3.3 +/- 0.48 mmol 1(-1); P less than 0.001). Thus, acute stress stimulates the sodium pump activity in erythrocytes of the rat and norepinephrine seems most likely to trigger this activation.
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PMID:Acute stress stimulates the red cell sodium pump in rat. 609 35

Plasma somatolactin (SL) concentrations in rainbow trout were examined under various physiological and environmental conditions. Background adaptation and feeding did not affect plasma SL levels. There was no consistent change in plasma SL levels during fasting for 21 days, although increased plasma growth hormone levels and decreased condition factor, hepatosomatic index and abdominal fat, occurred. Plasma SL concentrations increased during acute stress and also during exhaustive exercise resulting from being chased in shallow water. Elevation of plasma SL was associated with those of plasma cortisol, Ca2+, phosphate, and glucose levels. On the other hand, plasma level of prolactin was not affected in the stress and exercise experiments, although plasma GH and Na+ were raised in the fish 5 min after the onset of the stress. Our results suggest the involvement of SL in calcium and phosphate metabolism, acid-base regulation, or energy mobilization in the stressed or exercised trout.
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PMID:Effects of feeding, fasting, background adaptation, acute stress, and exhaustive exercise on the plasma somatolactin concentrations in rainbow trout. 763 67


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