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

The skin colour of red porgy, Pagrus pagrus, can be modified by exposure to different background colours. Red and white background colours brighten the dark skin colour that develops under common culture conditions in red porgy. To assess whether skin colour is also modified by aquaculture related handling stress, we subjected red porgy to 5 min of netting stress combined with air exposure. Fish kept on a white background have: (1) a lighter skin colour, which is not influenced by an acute stressor, (2) a less saturated red colour, which significantly decreases 24h post-handling, and (3) a similar hue as fish kept on a red background. The first plasma parameters to rise after application of the stressor are cortisol, lactate and Na(+); then, glucose levels rose. Other plasma ions (Ca(2+), Cl(-), K(+)) were not affected up to 2h post-stressor, but had decreased at 8 and 24h after handling. Plasma pH decreased over the first 2h post-handling, indicative of plasma acidosis upon air exposure. The acidosis then coincided with increases in plasma lactate levels. As alphaMSH levels were not significantly affected by the stressor while cortisol levels showed a five to tenfold increase, we suggest that following acute stress in red porgy, plasma cortisol release is controlled by ACTH, perhaps in combination with a sympathic stimulation.
Gen Comp Endocrinol 2006 Feb
PMID:The acute stress response of red porgy, Pagrus pagrus, kept on a red or white background. 1625 49

The endocrine stress response is pivotal in vertebrate physiology. The stress hormone cortisol-the end product of the endocrine stress axis-(re-)directs energy flows for optimal performance under conditions where homeostasis may be or become at risk. Key players in the continuous adaptation process are corticotropin-releasing factor (CRF) from the hypothalamic nucleus preopticus (NPO), pituitary adrenocorticotropic hormone (ACTH) and cortisol produced by the interrenal cells in the headkidney (adrenal equivalent of fish). CRF is a member of a large family of related peptides that signals through CRF-receptor subtypes specific for central and peripheral actions of the peptide. CRF is "chaperoned" by a unique and phylogenetically very well-conserved binding protein (CRFBP); the functions of the CRFBP can only be speculated on so far, but its mRNA and protein abundance are important indicators of the central CRF-system activity, and indeed its mRNA levels are altered by restraint stress. Moreover, the unique structure and size of the CRFBP provide good tools in phylogenetic studies, that date the CRF-system to at least one billion years old. Pro-opiomelanocortin is produced and processed to ACTH and endorphin in the hypothalamic NPO and pituitary pars distalis ACTH-cells, to MSH and acetylated endorphins in the pituitary pars intermedia MSH-cells. ACTH is the prime corticotrope in acute stress conditions. In carp, MSH, considered a mild corticotrope in chronic stress responses in other fish, lacks corticotropic effects (in line with the absence of the melanocortin-5 receptor in headkidney); yet, an unknown corticotropic signal substance in the pars intermedia of carp awaits elucidation. Interesting observations were made on the CRF control of pituitary cells. CRF stimulates ACTH-cells, but only when these cells experience a mild dopaminergic block. Endorphin, produced in the NPO and transported via axons to the pituitary gland in vivo, reverses the stimulatory CRF action on MSH-cells to a differential inhibition of N-acetyl beta-endorphin release in vitro (MSH release is not affected). We speculate that the consistently observed elevation of plasma MSH during chronic stress may exert central actions related to feeding and leptin regulated processes. A BOLD-fMRI study revealed the functional anatomy of the stress response at work in a paradigm, where carp were exposed to a sudden water temperature drop. In carp (and other fish), the endocrine stress axis is already operational in very early life stages, viz., around hatching and comprises hypothalamic, pituitary, and interrenal signaling to adjust the physiology of the hatchling to its dynamically changing environment. Understanding of stress during early life stages is critical as the consequent rises in cortisol may have long lasting effects on survival and fish quality.
Gen Comp Endocrinol 2006 Mar
PMID:CRF and stress in fish. 1640 2

In the wild, animals survive by responding to perceived threats with adaptive and appropriate changes in their behaviors and physiological states. The exact nature of these responses depends on species-specific factors plus the external context and internal physiological states associated with the stressful condition. The neuroendocrine mechanisms that control context-dependent stress responses are poorly understood for most animals, but some progress has been made recently. Corticotropin-releasing factor (CRF) plays an important role in mediating neuroendocrine, autonomic, and behavioral responses to stress. Across many vertebrate taxa, CRF not only stimulates the HPA axis by increasing the secretion of ACTH and glucocorticoid hormones, but also acts centrally by modifying neurotransmitter systems and behaviors. CRF or one of several CRF-related neuropeptides acts to stimulate locomotor activity during periods of acute stress. This behavioral activation consists of anxiety-related non-ambulatory motor activity, ambulatory locomotion, or swimming depending on the species and context. CRF-related neuropeptides increase swimming behaviors in amphibians and fish, apparently by activating brainstem serotonergic systems because the administration of fluoxetine (a selective serotonin re-uptake inhibitor) greatly enhances CRF-induced locomotor activity. Thus, our working model is that CRF, in part via interactions with brainstem serotonergic systems, modulates context-dependent behavioral responses to perceived threats, including both anxiety-related risk assessment behaviors and fight-or-flight locomotor responses.
Gen Comp Endocrinol 2006 Mar
PMID:Regulation of behavioral responses by corticotropin-releasing factor. 1642 6

In mammals, oestrogens generally stimulate adrenal function whilst androgens are inhibitory, and gestating females down-regulate their acute response to stressors in order to protect current reproductive investment. This study aimed to determine if adrenocortical function is similarly modulated by sex and reproductive status in the viviparous lizard, Egernia whitii. We compared the adrenocortical response to acute capture stress in female E. whitii during active (post-ovulatory and gestating) and quiescent (post-partum) phases of their reproductive cycle. We also compared the responses of reproductively quiescent males and females to acute stress and ACTH challenge to determine if there are sex-related differences in HPA axis activity when the influence of reproductive hormones is minimal. The females' responses to acute capture stress varied significantly with reproductive stage, and quiescent females displayed the strongest immediate response, with a rapid and sustained increase in plasma corticosterone (CORT) concentrations. Post-ovulatory females showed the most conservative adrenocortical response and while gestating females showed a large immediate response, this was not as prolonged as in quiescent females. Reproductively quiescent males and females exhibited similar responses to acute stress, and also responded similarly to ACTH injection, with plasma CORT reaching maximal concentrations of 52.1 and 59.4 ng/mL, respectively. Reproductively quiescent females treated with oestrogen exhibited greater responsiveness to ACTH than control females, although basal plasma CORT concentrations were unaltered: these results suggest that the attenuation of the acute stress response observed in reproductively active females of E. whitii may be regulated upstream of ACTH secretion. Our results demonstrate that the activity of the HPA axis is modulated by reproductive status in this viviparous reptile, and that gestating females are able to buffer their embryos from the potentially adverse effects of elevated plasma corticosteroids.
Gen Comp Endocrinol 2007 Jan 01
PMID:Does adrenal responsiveness vary with sex and reproductive status in Egernia whitii, a viviparous skink? 1697 39

Facilitation of the stress response results from a reduction of the inhibitory effects of circulating corticosteroids, allowing an animal to respond to a novel stressor. In this study, the existence of a facilitated cortisol stress response in normal (STD) and 17alpha-hydroxylase deficient XX mas-1/mas-1 (E5) carp was investigated. E5 carp had previously been characterized as having a low cortisol response to stress. Fish were subjected to either cortisol feeding or daily-acute stress, from 45 until 140 days post-hatch (dph) and were then subjected to a novel net-confinement stressor at 141 dph. Growth of E5 fish was reduced in both the daily-acute stress and cortisol-fed groups, but STD fish were only affected by daily-acute stress. Cortisol feeding had no effect on the stress response of STD fish but daily-acute stress significantly inhibited the response to a subsequent novel stressor. In contrast, daily-acute stress facilitated the cortisol stress response of E5 fish to a novel stressor, while cortisol feeding inhibited the cortisol response. Facilitation was accompanied by significant enlargement of the head-kidney tissue (which contains the steroidogenic interrenal tissue) in E5 fish. To our knowledge this is the first report of stress-induced facilitation in a lower vertebrate.
Gen Comp Endocrinol 2007 Feb
PMID:Stress-induced facilitation of the cortisol response in 17alpha-hydroxylase deficient XX mas-1/mas-1 carp (Cyprinus carpio). 1718 88

Chronic increases in stress hormones such as glucocorticoids are maladaptive, yet studies demonstrating a causal relationship among chronic stress, increases in glucocorticoid concentrations, and subsequent fitness costs in free-living animals are lacking. We experimentally induced chronic psychological stress in female European starlings (Sturnus vulgaris) by subjecting half of the females at our study site to a chronic stress protocol consisting of 4, 30 min stressors (loud radio, predator calls, a novel object, or predator decoys including a snake, rat, and owl) administered in random order daily for 8 days after clutch completion. Experimental females were captured at the end of the chronic stress protocol (9 days after the onset of the chronic stress protocol), and unstressed control females were captured at the same stage of the nesting cycle. Chronically stressed females had lower baseline corticosterone (CORT, the avian glucocorticoid) concentrations and lower reproductive success than unstressed females. Furthermore, surviving nestlings in experimentally stressed broods showed sensitization of the CORT response to acute stress, which is a physiological change that could persist to adulthood. Attenuation of baseline CORT concentrations in adult females is contrary to the general assumption that elevated CORT concentrations indicate stress, suggesting that more research is necessary before CORT concentrations can be used to accurately assess chronic stress in field studies.
Gen Comp Endocrinol 2007 Mar
PMID:Chronic stress in free-living European starlings reduces corticosterone concentrations and reproductive success. 1728 Jun 63

In order to understand the role of sympatho-adrenomedullary (SAM) system in mediating stress effect on non-specific immune responses in fishes, the splenic macrophage phagocytic and respiratory burst activities of normal and chemically sympathectomized Channa punctatus under restraint stress were studied. Chemical sympathectomy abrogated the differential effects of acute stress on diverse functions of macrophages. The SAM regulation of macrophage activities was substantiated by in vitro experiments with catecholamines, the end product of SAM system. Further, for the first time in fishes, different adrenoceptors and their precise second messenger system regulating diverse functions of macrophages by catecholamines were demonstrated. Norepinephrine (NE)/epinephrine (E) decreased the phagocytosis through beta-adrenergic receptor as only propranolol, the beta-adrenergic receptor antagonist, blocked the suppressive effect of NE/E. However, dopamine (DA) regulates phagocytosis solely via the dopaminergic receptor. The DA effect was mimicked by DA receptor agonists, apomorphine and bromocryptine. Adenylate cyclase system linked to beta-adrenoceptor/dopaminergic receptor seems to be involved in mediating the effect of catecholamine on phagocytosis since db cAMP inhibited the phagocytosis in a dose-dependent manner. In case of superoxide production, only phenoxybenzamine, an alpha-adrenergic receptor antagonist, was seen effective in blocking the stimulatory effect of NE/E. Further, Ca2+ as second messenger system coupled to alpha1-adrenergic receptor was shown to mediate this effect since phospholipase C (PLC) inhibitor, U73122 and intracellular calcium chelating agent, BAPTA-AM downregulated the NE/E-induced superoxide production. The role of calcium in modulation of superoxide production was also emphasized using calcium ionophore A23187.
Gen Comp Endocrinol 2008 Jan 15
PMID:Role of adrenoceptor-coupled second messenger system in sympatho-adrenomedullary modulation of splenic macrophage functions in live fish Channa punctatus. 1757 46

Although increases in glucocorticoid concentrations during acute stress are believed to help animals survive stressful events, chronic changes in glucocorticoid concentrations can alter metabolism and lead to disease. We studied the effect of chronic psychological stress on corticosterone (CORT), corticosterone binding globulin (CBG), glucose, and triglyceride concentrations as well as immune responsiveness to a T-cell mitogen challenge in European starlings, Sturnus vulgaris. To induce chronic stress we used a chronic stress protocol consisting of five stressors (loud radio, cage tapping, cage rolling, human voice, and bag restraint) administered in random order for 30 min for 4 times/day over 18 days. Total CORT decreased throughout the chronic stress period, which parallels a previous study with starlings. CBG capacity did not significantly change with chronic stress, thus free CORT followed the same pattern of attenuation as total CORT during chronic stress. Despite the change in regulation of CORT release, daytime glucose and triglyceride concentrations did not change with chronic stress. In addition, immune responsiveness in chronically stressed and unstressed birds was similar. Our results, together with a previous study using a similar CSP in European starlings, suggest that starlings physiologically dampen the HPA axis during chronic psychological stress to avoid pathology associated with chronically augmented CORT concentrations such as hyperglycemia and impaired immune function.
Gen Comp Endocrinol
PMID:The effect of chronic psychological stress on corticosterone, plasma metabolites, and immune responsiveness in European starlings. 1768 4

The question of whether changes in glucocorticoid concentrations reflect consistent changes in physiology associated with transitions between different stages of reproduction, or whether they reflect responses to environmental conditions, is one the central issues in field endocrinology studies. We examined the temporal and spatial dynamics of corticosterone (CORT, baseline, and acute stress-induced) and corticosterone binding globulin (CBG) concentrations in blood of Black-legged Kittiwakes (Rissa tridactyla) breeding at four major colonies in the Bering Sea, Alaska, during 1999-2005. We found that total CORT, free CORT, and CBG capacity varied inconsistently among reproductive stages, colonies, and years. Total CORT levels were positively correlated with CBG capacity. Variation in free CORT was largely driven by variation in total CORT. Results suggest that the adrenocortical function and CBG in breeding kittiwakes do not vary as a consequence of stage-specific modulation associated with a particular reproductive stage as in some short-lived passerine birds. Rather, in accord with predictions for a long-lived species, the lack of consistent colony, year, and reproductive stage patterns in baseline and maximum CORT, and CBG indicates that environmental factors, probably local dynamics of food availability, drive variation in these factors.
Gen Comp Endocrinol 2008 Feb 01
PMID:Spatial and temporal dynamics of corticosterone and corticosterone binding globulin are driven by environmental heterogeneity. 1816 97

Seasonal modulation of the adrenocortical response to stress appears to be ubiquitous in arctic-breeding and temperate-zone-breeding birds, but has not been well investigated in alpine-breeding species at mid-latitude. We examined the adrenocortical response to acute stress (capture, handling and restraint) in populations of Eurasian tree sparrow (Passer montanus) among seasons and migratory house sparrow (P. domesticus bactrianus) in pre-breeding on the Qinghai-Xizang Plateau (the Tibetan Plateau). A population of house sparrow (Passer domesticus domesticus) was also sampled in lowland Phoenix, Arizona during breeding and wintering stages. In Eurasian tree sparrows, baseline corticosterone (CORT) does not differ among life history stages, but stress-induced CORT level (maximal CORT, total and corrected integrated CORT) is significantly higher in late breeding stage than those in early breeding and prebasic molt stages. In house sparrows, stress-induced CORT level does not differ between sites and life history stages, but baseline CORT is significantly lower in pre-breeding from Qinghai compared with those in breeding and wintering stages from Phoenix. Interestingly, both baseline CORT and maximal CORT do not differ between the populations of Eurasian tree sparrow and house sparrow in early/pre-breeding stage although tree sparrow is resident species whereas house sparrow is migratory in Qinghai. Our results suggest that the extreme environment of the Tibetan Plateau does not have significant effects on adrenocortical responses to acute stress in Eurasian tree sparrows and house sparrows, which may be a result of masking by human activities. These invasive human commensals may have a unique HPA axis response to different environments because they can take advantage of human food sources and shelter (i.e. buildings).
Gen Comp Endocrinol 2008 Aug
PMID:Seasonal changes in adrenocortical responses to acute stress in Eurasian tree sparrow (Passer montanus) on the Tibetan Plateau: comparison with house sparrow (P. domesticus) in North America and with the migratory P. domesticus in Qinghai Province. 1858 92


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