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

The production of cytokines by alveolar macrophages was studied after exposure of rats to an acute stress paradigm (mild inescapable footshocks). When alveolar macrophages from nonstressed animals were isolated and cultured, they readily produced interleukin-1 beta (IL-1 beta), IL-6, and tumor necrosis factor-alpha (TNF-alpha) after stimulation with lipopolysaccharides (LPS). For these cytokines the dose response relationship for LPS was clearly biphasic. Nitric oxide (NO) production could only be detected upon LPS stimulation and seemed to be monophasic. However, when the animals were exposed to the acute stress paradigm, isolated alveolar macrophages (AM) showed a marked increase of IL-1 beta and TNF-alpha secretion upon LPS stimulation in vitro, but no changes in the production of IL-6 were detected. In contrast, exposure to the stress paradigm resulted in a strong decrease in NO production. The results indicate that emotional stress can rapidly induce altered behavior of AM, which is discussed in view of the important role these cells play in the regulation of the local immune responses in the lungs and the possible contribution to asthma.
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PMID:Acute stress affects cytokines and nitric oxide production by alveolar macrophages differently. 763 16

This study was conducted to investigate the role of the acute stress hormone adrenaline on macrophage nitric oxide (NO) production. Murine peritoneal macrophages were stimulated in vitro with lipopolysaccharide (LPS) in the absence or presence of adrenaline. Adrenaline inhibited the LPS-induced nitrite response in a dose-dependent manner. The suppressive effect of adrenaline on NO production was mediated via beta1 and beta2 adrenergic receptors since isoprenaline (a non-selective beta1 and beta2 agonist), dobutamine and salbutamol (selective beta1 and beta2 agonists, respectively) had similar effects on the NO response. In addition, the inhibitory effect of adrenaline on NO was abrogated by both propranolol (a non-specific beta blocker) and atenolol (a specific beta1 inhibitor). In contrast to beta receptor activation, the alpha adrenergic agonist phenylephrine had no effect on the LPS NO response, and furthermore, phentolamine (an alpha receptor antagonist) did not ameliorate adrenaline's inhibitory action.
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PMID:Adrenaline inhibits macrophage nitric oxide production through beta1 and beta2 adrenergic receptors. 1092 58

The underlying mechanisms by which physical or psychological stress causes neurodegeneration are still unknown. We have demonstrated that the high-output and long-lasting synthesizing source of nitric oxide (NO), inducible NO synthase (iNOS), is expressed in brain cortex during stress and that its overexpression accounts for the neurodegenerative changes seen after 3 weeks of repeated stress. Now we have found that acute stress (restraint for 6 h) increases the activity of a calcium-independent NOS and induces the expression of iNOS in brain cortex in adult male rats. In order to elucidate the possible mechanisms involved in this induction, we studied the role of transcription nuclear factor kappaB (NF-kappaB), which is required for iNOS synthesis. We have observed that an acute restraint stress session stimulates the translocation of the NF-kappaB to the nucleus after 4 h and that the administration of the NF-kappaB inhibitor pyrrolidine dithiocarbamate [PDTC, 75 and 150 mg/kg intraperitoneally (i.p.)] at the onset of stress inhibits the stress-induced increase in iNOS expression. Since glutamate release and subsequent NMDA (N-methyl-D-aspartate) receptor activation has been recognized as an early change after exposure to stressful stimuli, and glutamate has been shown to induce iNOS in brain via a NF-kappaB-dependent mechanism, we studied the possible role of excitatory amino acids in the induction of iNOS in our model. Pretreatment with the NMDA receptor antagonist dizocilpine (MK-801, 0.1 and 0.3 mg/kg i.p.) inhibits the stress-induced NF-kappaB activation as well as the stress-induced increase in iNOS expression. Taken together, these findings indicate that excitatory amino acids and subsequent activation of NF-kappaB account for stress-induced iNOS expression in cerebral cortex, and support a possible neuroprotective role for specific inhibitors in this situation.
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PMID:Inducible nitric oxide synthase expression in brain cortex after acute restraint stress is regulated by nuclear factor kappaB-mediated mechanisms. 1120 16

Adrenaline is a catecholamine hormone secreted by the adrenal medulla in response to acute stress. Previous studies have shown that adrenaline suppresses the nitric oxide (NO) response of murine macrophages (M phi s) stimulated in vitro with lipopolysaccharide (LPS). We have now extended these studies to examine the effects of adrenaline on the production of tumour necrosis factor alpha (TNF-alpha) and interleukin-10 (IL-10). Our results showed that NO, TNF-alpha and IL-10 were concurrently produced following in vitro LPS (10 micrograms/ml) stimulation of murine peritoneal M phi s. Adrenaline suppressed both NO and TNF-alpha with concomitant up-regulation of the IL-10 response above that seen with LPS alone. In this in vitro model of LPS stimulation we demonstrated that TNF-alpha was required for NO production, as the TNF-alpha neutralizing monoclonal antibody, TN3.19.12, abolished the response; in contrast, IL-10 suppressed NO. In order to determine any functional consequence of adrenaline-mediated IL-10 augmentation on NO production, M phi s were stimulated with LPS and specific neutralizing anti-IL-10 antibodies were added to the cultures. The LPS NO response was suppressed to 43% of the control value by adrenaline (10(-8) M) and an irrelevant control antibody had no effect on the adrenaline-mediated inhibition of NO, but anti-IL-10 treatment restored the NO response to levels similar to those observed with LPS alone. Furthermore, we demonstrated that exogenous TNF-alpha, at a dose range of 1.9-50 ng per ml, also restored the nitrite response to LPS in the presence of adrenaline. Together, the observations that neutralization of IL-10 and addition of TNF-alpha abrogate adrenaline's inhibition of NO, suggest that this hormone suppresses NO partly through up-regulation of IL-10 which, in turn, may suppress TNF-alpha that is required for NO production. Finally, we also observed that the M phi-activating cytokine, interferon-gamma (IFN-gamma), attenuated the inhibitory effect of adrenaline on the LPS NO response.
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PMID:Adrenaline suppression of the macrophage nitric oxide response to lipopolysaccharide is associated with differential regulation of tumour necrosis factor-alpha and interleukin-10. 1189 30

Stress is a factor found to be involved in the etiology of many diseases. Gender and menstrual cycle phases are other factors affecting the predisposition of individuals for certain diseases. Results from animal and human studies suggest that the distribution of immune system cells may change at different phases of the menstrual cycle. Acute mental stress in humans alters immune variables, too. The increase in the number of natural killer (NK) cells is the most consistent finding among the immune variables, though there are controversies for the other lymphocyte groups. Nitric oxide (NO) as an immune mediator has an unsettled role whether it causes the redistribution of the immune cells, or is an end product of lymphocyte activation. This study was planned to investigate the effect of mental stress on lymphocyte subtypes and the role of NO, for men and women at different phases of the cycle. For this purpose, healthy men (n = 10) and women (n = 10), during the follicular and luteal phases underwent Stroop colour-word interference and cold pressor tests. The immune system responses before and after the tests were determined by cell counts with the flowcytometer. Menstrual cycle phase was ascertained by plasma estrogen and progesterone measurements. Stress response was evaluated by blood pressure (BP) and heart rate (HR) measurements throughout the tests and plasma cortisol and urinary metanephrine and vanillylmandelic acid (VMA) measurements before and after the tests. Plasma and urinary NO determinations were performed before and after the test was completed. All the results were analysed with the appropriate statistical methods. The luteal phase differed from the other groups due to the presence of suppressed immune response to acute stress, including decreased CD4/CD8 ratio and NK cell percentage. On the other hand, acute stress caused a shift from cellular to humoral immunity in men. As indicated by these results, individual reaction towards stress is affected by gender and menstrual cycle phase. NO appears to be a possible effector molecule for these differences.
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PMID:Impact of stress, gender and menstrual cycle on immune system: possible role of nitric oxide. 1193 78

Disaster workers as well as victims are at increased risk for acute stress disorder (ASD). The present study was undertaken to study the course of the stress response in a group 187 young, male military personnel who served as rescue workers for 3 days after an earthquake in central Taiwan. A control group of 83 young, male military personnel who remained on the base was also studied. The initial evaluation took place within 16 days of the earthquake. Participants were interviewed using the Mini International Neuropsychological Interview. Thirty-one individuals met DSM-IV criteria for ASD at the initial evaluation. These 31 individuals were interviewed a second time 1 month after the earthquake. Plasma samples were also collected and assayed for nitric oxide (NO). The point prevalence rates of ASD 2 weeks after the earthquake in the initial evaluation were 9 and 16% in the rescue worker and control groups, respectively. At 1 month, the prevalence was substantially lower, in the range of 2-3%. Significant inverse correlations were observed between severity of stress symptoms and the plasma concentration of NO in the rescue worker group (r=-0.36 to -0.64, n=17, P<0.05). We conclude that young military personnel without formal training in rescue operations are at risk for ASD, but their risk appears to be no higher than that in a similarly composed control group of young military personnel. Longitudinal studies with plasma measures of NO are needed to clarify its potential role in the development and course of ASD and related syndromes.
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PMID:Characteristics of acute stress symptoms and nitric oxide concentration in young rescue workers in Taiwan. 1237 51

Exposure to acute stress modulates immune function. Most research regarding stress and immunity has described the deleterious effects of stress. Recent studies, however, indicate that acute stress enhances many features of innate immunity. For example, exposure to acute stress reduced the time required to resolve inflammation produced by subcutaneous injection of streptomycin-killed, benign bacteria. It is unclear if this change in inflammation would be advantageous to the organism if challenged with living, infectious bacteria. Thus, the current experiments examined the effect of acute stressor exposure on inflammation development and resolution after a naturalistic, live bacterial challenge. In addition, nitric oxide (NO), an important bactericidal mediator, was measured at the inflammatory site. Rats (F344) were exposed to acute stress (100, 5-s, 1.6 mA tailshocks) and subcutaneously injected with live Escherichia coli ( approximately 2.5 x 10(9) colony forming units [CFU]). Stressed rats attained their peak inflammatory size quicker, resolved their inflammation 10-14 days faster, experienced less bacterial-induced weight loss and released 300% greater NO at the inflammatory site than nonstressed controls. Thus, acute stress improved recovery from bacterially induced inflammation possibly due to local elevations in NO.
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PMID:Acute stress decreases inflammation at the site of infection. A role for nitric oxide. 1241 5

A hypothesis is substantiated in accordance to which a resistance of an organism to stress damages depends upon genetically determined peculiarities of its regulatory stress-limiting systems that restrict stress reaction and its detrimental effects. A comparison of differences between the stress resistance and the activity of the stress-limiting systems (dopaminergic, serotoninergic, nitric oxide and heat shock proteins systems) in rats of two strains August and Wistar indicates that the higher hereditary activity of mentioned systems is associated with the higher resistance to acute emotional stress; and the lower hereditary activity of these systems associated with the lower resistance to this stress. At the same time the adaptation to repeated non-damaging exposures to stressor aimed to rise the stress resistance leads to opposite results in rats of the mentioned strains. In the animals with the higher hereditary resistance to acute stress (August rats) the adaptation reduces this resistance. In the animals with the lower hereditary stress resistance (Wistar rats) that sort of adaptation really rises this resistance. That is determined by changes in activity of the stress-limiting systems during repeated stress exposures. In the animals with the higher hereditary activity of the stress-limiting systems the adaptation reduces the activity of these systems. In the animals with the lower hereditary activity of the stress-limiting systems the adaptation rises this activity and the resistance of these animals to stress damages.
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PMID:[Inherent efficiency of stress-limiting systems as a factor of the resistance to stress-induced disorders]. 1294 62

The purpose of the present study was (i) to compare secretory responses of prolactin and corticosterone to the acute stress of immobilization in male rats of the Lewis and Long Evans strains and (ii) to compare secretion of the two hormones in rats with fully developed adjuvant arthritis (AA) and their relationship with the intensity of the inflammatory reaction. A short immobilization of 5 min induced equal elevations of both hormones in both strains, but 20-min immobilization produced significantly stronger responses in Long Evans rats than in Lewis rats. AA inhibited prolactin secretion equally in both strains (from 11.6 +/- 1.3 ng/ml to 4.2 +/- 0.6 ng/ml in Lewis rats, p < 0.01, and from 3.7 +/- 0.6 to 2.12 +/- 0.1 ng/ml in Long Evans rats, p < 0.05), but caused a conspiciously larger elevation of corticosterone in the Long Evans than in the Lewis animals (11.5 +/- 1.2 microg/dl in Long Evans rats versus 5.1 +/- 0.5 microg/dl in Lewis rats, p < 0.01) while basal levels were similar. The larger corticosterone response in the Long Evans rats was associated with a stronger inflammatory reaction assessed by hind paw swelling (2.3 +/- 0.1 ml for Long Evans rats versus 1.8 +/- 0.08 ml for Lewis rats, p < 0.01) and plasma levels of nitric oxide (47.5 +/- 5.7 microM for Long Evans rats versus 28.7 +/- 2.5 microM for Lewis rats, p < 0.01) than in the Lewis males with lower corticosterone levels. In conclusion, there are significant, obviously genetically based, differences in the corticosterone responses to both immobilization and AA between the two strains, with the Long Evans rats reacting more strongly than the Lewis rats. The lack of the expected inverse relationship between corticosterone levels and the intensity of the inflammation indicates that the activity of corticosterone is not its primary determinant and that other important factors are involved.
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PMID:Differences in hormonal and inflammatory parameters in male Lewis and Long Evans rats with adjuvant arthritis. 1475 91

Superoxide has been shown to be an important intracellular mediator of actions of angiotensin II. Recently, we found that blockade of angiotensin II type-1 receptors in the rostral ventrolateral medulla (RVLM) abrogated the pressor effect of emotional stress in rabbits. In the present study, we examined the influence of superoxide dismutase mimetics, tempol and tiron, in RVLM on cardiovascular stress response in conscious rabbits. Air-jet stress evoked a sustained increase in blood pressure (+14+/-2 mm Hg), tachycardia (+52+/-7 bpm), and renal sympathoactivation (+58+/-8%). Bilateral microinjections of tempol or tiron (20 nmol) into RVLM did not alter resting cardiovascular parameters, but attenuated the pressor, sympathetic, and tachycardiac response to stress by 40% to 55%. By contrast, 3-carbamoylproxyl, which is structurally close to tempol but has a lower superoxide scavenging activity, did not alter the stress response. Neither tempol nor tiron altered the sympathoexcitatory response to glutamate microinjections into RVLM or to baroreceptor unloading. Microinjections of nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME; 10 nmol) into RVLM did not affect the stress response. Coinjections of tempol and L-NAME decreased the pressor response to stress by 35+/-3%. Tempol attenuated the pressor response to microinjection of angiotensin II into RVLM by 59+/-15%, whereas L-NAME did not alter this response. These results suggest that superoxide dismutase mimetics in RVLM attenuate, partially via a nitric oxide-independent mechanism, the pressor effect of emotional stress in rabbits. Together with our previous studies, these results also indicate that superoxide is a key mediator of excitatory actions of angiotensin II in RVLM during acute stress.
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PMID:Tempol attenuates excitatory actions of angiotensin II in the rostral ventrolateral medulla during emotional stress. 1515 79


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