Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0848237 (acute stress)
 4,619 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Antalarmin is a pyrrolopyrimidine compound that antagonizes corticotropin-releasing hormone (CRH) type 1 receptors (CRHR1). In order to assess the effects of antalarmin treatment on hypothalamic-pituitary-adrenal (HPA) function we measured the plasma concentrations of adrenocorticotropic hormone (ACTH) and corticosterone in animals treated with either antalarmin or vehicle for 1 week or for 8 weeks. We found that antalarmin treatment for 1 week did not affect basal concentrations of ACTH or corticosterone. In contrast, treatment for 8 weeks significantly lowered basal ACTH and corticosterone concentrations and also significantly decreased the basal corticosterone to ACTH ratio, indicating decreased basal adrenocortical responsiveness to ACTH. However, immobilization stress resulted in ACTH and corticosterone concentrations that were the same in animals treated with vehicle or antalarmin for either 1 or 8 weeks. We conclude that even though 8-week antagonism of CRHR1 by the non-peptide antalarmin blunts basal concentrations of ACTH and corticosterone, and affects the adrenal responsiveness to ACTH, it does not blunt the HPA response to acute stress, and it does not appear to cause stress-induced adrenal insufficiency.
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PMID:Chronic administration of the non-peptide CRH type 1 receptor antagonist antalarmin does not blunt hypothalamic-pituitary-adrenal axis responses to acute immobilization stress. 1042 33

During early development, environmental challenges set the stage for permanent changes in the functioning of the pituitary-adrenal stress response. Since these data have been reported almost exclusively in single rat strains the role of phenotypic and genotypic factors in shaping the stress response is relatively unknown. This study examined whether the phenotypic/genetic profile of the rat influences the long-term response to challenge after early exposure to stress. Two strains of Sprague-Dawley rats were used in this study: one is a stress-induced animal model of "learned helpless" (LH) behavior and the other a resistant strain developed through selective breeding. Stress-induced adrenocorticotropic hormone (ACTH) and corticosterone release was monitored in adult congenital learned helpless (cLH) rats and congenital non-learned helpless (cNLH) rats. The rats were exposed to cold stress or maternal deprivation (on either postnatal day 7 or day 21). After the early acute stress exposure, animals remained undisturbed until challenged in adulthood (day 90) with footshock stress. In cLH animals (adults) early cold stress (particularly after acute stress on postnatal day 21) and maternal deprivation stress resulted in an enhancement of stress-induced ACTH release compared to nonstressed cLH and cNLH controls. In contrast, adrenal responsiveness was generally suppressed in cLH animals that were acutely stressed with cold stress or maternal deprivation stress early in life. The above results suggest that the genetic/phenotypic profile of the animal is a determinant in the changes observed in the adult stress response after early exposure to stressors.
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PMID:Early stress and genetic influences on hypothalamic-pituitary-adrenal axis functioning in adulthood. 1050 32

The Otsuka Long-Evans Tokushima Fatty (OLETF) rat is a new diabetic strain of rats whose disease closely resembles human type 2 diabetes. We measured plasma adrenocorticotropic hormone (ACTH) and corticostrone levels, and iodine-125-labeled ovine corticotropin-releasing factor ([125I]oCRF) binding in the anterior pituitary after ether-laparotomy stress in OLETF rats to examine the alteration of the hypothalamic-pituitary-adrenal (HPA) axis. In addition, we examined ACTH secretion following CRF administration in vivo and in vitro to characterize the mechanisms regulating the HPA axis in OLETF rats. Body weight, plasma glucose and insulin levels in OLETF rats were significantly higher than that in Long-Evans Tokushima Otsuka (LETO) rats. Basal plasma ACTH levels tended to be higher in OLETF rats than in LETO but it did not reach statistical significance. Ether-laparotomy stress dramatically increased plasma ACTH levels at 2 h after the stress both in either OLETF and LETO rats; the peak plasma ACTH level in OLETF rats following the stress was significantly greater than in LETO rats. Plasma ACTH levels following CRF (2 microg/kg, i.v.) in OLETF and LETO rats showed statistically significant increases at 10 and 30 min after CRF administration compared to ACTH levels at 0 min, however, the peak plasma ACTH level in OLETF rats at 10 min after CRF administration was significantly greater than in LETO rats. In contrast to ACTH levels, no significant differences in corticosterone levels between OLETF and LETO were observed at any of the time points. CRF (10 ng/ml) significantly increased ACTH secretion in pituitary cultures from OLETF compared to LETO rats. These data reveal a complex regulation of the endocrine system in this diabetic condition and suggest that HPA axis may be more stimulated during acute stress in diabetes mellitus than in unaffected subjects.
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PMID:Increased adrenocorticotropin responses to acute stress in Otsuka Long-Evans Tokushima Fatty (type 2 diabetic) rats. 1066 2

Secretion of adrenocorticotropic hormone (ACTH) from the fish pituitary, which occurs in times of stress, is stimulated by several hypothalamic neuropeptides, one of which is arginine vasotocin (AVT). This study investigates whether gene expression for AVT is up-regulated during acute or chronic stress. Rainbow trout (Oncorhynchus mykiss) were subjected to one of two forms of acute stress-either 2 h confinement followed by 2 h recovery, or capture and transfer to low water for 2 min followed by 4 h recovery in their home tank before autopsy. In other experiments, these stresses were repeated daily for 5 or 6 days (chronic stress). Quantification of AVT transcript prevalence in the parvocellular and magnocellular neurones of the preoptic nucleus after in situ hybridization was used as a monitor of the AVT gene response to stress. The results showed that acute confinement, but apparently not brief low-water stress, significantly increased AVT transcript prevalence in a group of parvocellular perikarya. When applied repeatedly, both forms of stress caused habituation, such that the AVT hybridization signal remained at control or even lower levels despite elevated pro-opiomelanocortin transcripts in the corticotropes and raised plasma cortisol concentrations. The AVT hybridization signal in the magnocellular perikarya showed no significant response to either acute or chronic stress. The results support the idea that these parvocellular AVT neurones are involved in ACTH stimulation during acute stress, and that the system habituates to chronic stresses.
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PMID:The effects of acute and chronic stresses on vasotocin gene transcripts in the brain of the rainbow trout (Oncorhynchus mykiss). 1092 92

In birds, additional adrenocortical secretion in response to stressors often redirects an individual's ongoing activities toward immediate life-saving activities, usually by facilitating an increase in food searching and food intake needed to meet periods of increased energy demand. We asked whether young birds, who are entirely dependent on parents for food acquisition and therefore unable to manipulate their own food intake, fail to show an adult-like adrenocortical response to the acute stress of capture and handling. In 1998, plasma profiles of acute corticosterone secretion (e.g., samples taken at the time of capture and 30 min later) were compared across seven age classes of Northern Mockingbirds (Mimus polyglottos) representing various age-related stages of foraging ability and opportunity. As predicted, young birds less able, or entirely unable, to readjust their own foraging effort exhibited significantly lower stress responses compared to adults. The magnitude of the stress response (at 30 min postcapture) increased and approached that of adults as young birds approached independence. Energetic condition was not correlated with the magnitude of the stress response at any age, suggesting that variation in its expression was most likely due to age alone. We also investigated at what level within the hypothalamic-pituitary-adrenal (HPA) axis the corticosterone response may be controlled in young birds. In 1999, baseline corticosterone samples were taken in 8-day-old nestlings and were immediately followed by intrajugular injections of adrenocorticotropic hormone (ACTH) or saline. While plasma corticosterone concentrations did not change in saline-injected nestlings, ACTH-injected nestlings showed a significant increase in plasma corticosterone concentrations similar to 30-min samples taken from adults. These results indicate that, while young birds do not normally show the corticosterone response, the adrenocortical tissue has the capacity to do so, and the control appears to be within the hypothalamic-pituitary component of the HPA axis. Collectively, our results indicate that the expression of the corticosterone stress response develops in concert with a young, altricial bird's ability to utilize it as it approaches independence; the reduced corticosterone secretion may also allow young, rapidly growing birds to avoid potential deleterious exposure to elevated glucocorticosteroid concentrations.
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PMID:Development of the corticosterone stress response in young northern mockingbirds (Mimus polyglottos). 1093 39

IL-18 is a pleiotropic cytokine also proposed to have a role in modulating immune function during stress. Initially found in immune cells, IL-18 mRNA is detectable in several tissues including the cells of the zona reticularis and the zona fasciculata of the adrenal cortex, where its levels are elevated by acute stress or adrenocorticotropic hormone treatment. In the present study, we compared the expression of IL-18 in the adrenal cortex with that of spleen and duodenum, two other IL-18-positive tissues. In situ hybridization showed that, in contrast to the adrenal cortex, in spleen and duodenum IL-18 is primarily localized to immune cells. In duodenum, IL-18 mRNA was also detectable in epithelial cells. Northern blot demonstrated that while the adrenal gland synthesized IL-18 mRNA of 1.1 kb, spleen and duodenum produced a 0.9-kb transcript. RT-PCR, sequencing, Western blot, primer extension, and rapid amplification of cDNA end analysis demonstrated that the three tissues synthesize IL-18 mRNAs containing the same coding region and produce the same IL-18 peptide, but differ in the length of their 5'-untranslated region, indicating tissue-specific usage of the promoter region. Finally, in contrast to the adrenal gland, adrenocorticotropic hormone treatment did not increase the levels of IL-18 mRNA in spleen and duodenum. These results demonstrate tissue-specific expression and promoter usage of IL-18 gene and suggest that the adrenal cortex and not immune cells may be the source of IL-18 during stress.
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PMID:Tissue-specific expression of rat IL-18 gene and response to adrenocorticotropic hormone treatment. 1108 64

The effects of chronic immune challenge on cytokine expression and hypothalamic-pituitary-adrenal axis (HPA) axis responses to stress were studied in Wistar rats after administration of increasing doses of lipopolysaccharide (LPS). Repeated LPS (R-LPS) decreased body weight and increased adrenal weight and pituitary pro-opiomelanocortin mRNA levels. LPS injection increased plasma adrenocorticotropic hormone (ACTH) and corticosterone but the effect was attenuated in R-LPS. Plasma corticosterone but not ACTH responses to restraint were also reduced in R-LPS. Basal and restraint-stimulated corticotropin releasing hormone (CRH) mRNA levels were lower in R-LPS, but responses to a new LPS injection were similar to controls. In contrast, type 1 CRH receptor (CRH-R1) mRNA responses to both LPS and restraint were blunted in R-LPS. Vasopressin mRNA levels in parvocellular neurones were higher in R-LPS, and increased further after restraint but not after a new LPS injection. Glucocorticoid receptor (GR) levels in the paraventricular nucleus (PVN) increased after a single LPS or R-LPS (24 h after the last injection) but declined after a new injection in R-LPS. Interleukin (IL)-1beta and IL-6 mRNAs increased in the pituitary, spleen and circumventricular organs after single or R-LPS, suggesting that cytokines may contribute to the activation of the HPA axis though pathways from the circumventricular organs as well as paracrine effects in the pituitary. The data show that (i) adaptation of the HPA axis during repeated LPS injection involves increases in vasopressin : CRH expression ratios in parvocellular neurones; (ii) that hypothalamic CRH and vasopressin responses to acute stimulation are independent of CRH-R1 expression in the PVN; and (iii) there is a dissociation between pituitary and adrenal responses to acute stress suggesting a decrease of adrenal sensitivity to ACTH.
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PMID:Effect of repeated lipopolysaccharide administration on tissue cytokine expression and hypothalamic-pituitary-adrenal axis activity in rats. 1148 88

Consistent findings in depressed patients are hyperactivity in the hypothalamic-pituitary-adrenal (HPA) axis with high plasma concentrations of adrenocorticotropic hormone and cortisol. Long-term antidepressant treatments seem to normalize this hyperactivity, suggesting a link between the HPA axis and the action of antidepressant treatments. The present study was carried out to study the effects of antidepressant treatments on pro-opiomelanocortin (POMC) mRNA expression, with a focus on interaction with acute stress and 5-HT(1A) receptor activation. Male rats were treated for 21 days with saline, citalopram, fluoxetine, moclobemide or desipramine, and the expression of POMC mRNA in the anterior pituitary was analysed by semi-quantitative in situ hybridization. All antidepressants, but not saline, cocaine and haloperidol, reduced POMC mRNA expression. The decrease in POMC mRNA was not observed until 9 days of citalopram treatment. Decreased POMC mRNA levels were also observed after 14 days of repeated electroconvulsive stimulation. The decreased POMC mRNA levels did not affect the stress-induced POMC mRNA increase, measured following swim stress and restraint stress. Finally, using Fos as a marker for neural activity, we showed attenuation of 8-OH-DPAT-stimulated activity in the paraventricular nucleus following 21 days of citalopram treatment. In conclusion, antidepressant treatments decrease basal POMC mRNA expression without affecting the acute stress response, and the reduced POMC mRNA may be related to reduced 5-HT(1A)-stimulated hypothalamic output.
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PMID:Chronic antidepressant treatments decrease pro-opiomelanocortin mRNA expression in the pituitary gland: effects of acute stress and 5-HT(1A) receptor activation. 1167 57

We examined the role of the posterior division of the paraventricular nucleus of the thalamus (pPVTh) in habituation of hypothalamic-pituitary-adrenal (HPA) responses to repeated restraint. Habituation refers to the decrement in HPA activity that occurs with repeated exposure to the same or homotypic stressor. To date, the pPVTh has been shown to inhibit the enhanced or facilitated HPA responses to novel, heterotypic restraint in previously chronically cold stressed rats. We hypothesized that the pPVTh also inhibits HPA activity under conditions of habituation. In the first experiment, we lesioned the pPVTh and examined adrenocorticotropic hormone (ACTH) and corticosterone responses to the first or eighth restraint exposure. In sham-lesioned rats, we found lower ACTH and corticosterone responses to the eighth period of 30 min restraint compared to the first exposure, evidence for habituation. In pPVTh-lesioned rats, there was no difference in ACTH and corticosterone responses to the eighth compared to the first restraint exposure. Therefore, pPVTh lesions prevented the habituation of HPA responses to repeated restraint. In the second experiment, we examined whether habituation to restraint is observable in response to an acute, single restraint on day 28 in sham and pPVTh lesioned rats that were exposed to restraint only on days 1 through 8. In this experiment, we replicated the results from the first experiment, and found evidence that habituation to restraint can be observed weeks after chronic stress has been terminated. Furthermore, pPVTh lesions had no additional effects on HPA responses to acute stress on day 28. In summary, pPVTh lesions inhibit habituation of HPA activity to a homotypic stressor, without altering HPA responses to the first restraint. Thus, the intact pPVTh inhibits HPA activity under conditions of habituation, as well as facilitation, and represents an important regulator of HPA activity under conditions of chronic stress.
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PMID:Lesions of the posterior paraventricular thalamus block habituation of hypothalamic-pituitary-adrenal responses to repeated restraint. 1200 May 46

It is well known that stress affects the central nervous system (CNS), neuroendocrinoimmune system and other peripheral organs such as the gastrointestinal tract. However, the process of adaptation or recovery after acute stress reactions in these systems or organs during prolonged stress has not yet been adequately investigated. To clarify the process of adaptation or recovery in these systems and organs after acute stress reactions, the time course of these responses during a single long-duration restraint stress (RTS) was studied. The expression of c-fos in the hypothalamic paraventricular nucleus (PVN) region of the brain was induced and reached a peak at 0.5 hours for c-fos mRNA and 4 hours for c-fos protein (Fos), but disappeared at 2 hours for mRNA and 16 hours for Fos during continuous RTS. The activation of the hypothalamic-pituitary-adrenal (HPA) axis during stress resulted in rapid increases in the plasma levels of adrenocorticotropic hormone (ACTH) and corticosterone (CORT). Whereas the increase in ACTH was transient, the rise in CORT was maintained throughout the duration of the stress. A rapid significant decrease after stress exposure and following a slow and complete or partial recovery were observed in a number of total white blood cells (WBC), lymphocytes (LYM), helper T cells (Th) and cytotoxic/suppressor T cells (CTL/Ts). A gastric ulcer was found in 1/6 and 6/6 rats at 8 hours and 16 hours RTS, respectively. These results suggest that adaptive changes may occur in c-fos expression in the PVN, ACTH release and immune response, but not for CORT release, following acute stress reaction during long-duration RTS. In addition, any associated organic damage, such as gastric ulceration, was also suggested to possibly be progressive according to the duration of RTS.
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PMID:PVN c-fos expression, HPA axis response and immune cell distribution during restraint stress. 1206 82


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