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

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

Studies of behavior, endocrinology and physiology have described experiments in which animals housed in groups or in isolation were normally tested individually. The isolation of the animal from its group for testing is perhaps the most common situation used today in experimental procedures, i.e., there is no consideration of the acute stress which occurs when the animal is submitted to a situation different from that it is normally accustomed to, i.e., group living. In the present study, we used 90 male 120-day-old rats (Rattus norvegicus) divided into 5 groups of 18 animals, which were housed 3 per cage, in a total of 6 cages. The animals were tested individually or with their groups for exploratory behavior. Hormones were determined by radioimmunoassay using specific kits. The results showed statistically significant differences between testing conditions in terms of behavior and of adrenocorticotrophic hormone (ACTH: from 116.8 +/- 15.27 to 88.77 +/- 18.74 when in group and to 159.6 +/- 11.53 pg/ml when isolated), corticosterone (from 561.01 +/- 77.04 to 1036.47 +/- 79.81 when in group and to 784.71 +/- 55.88 ng/ml when isolated), luteinizing hormone (from 0.84 +/- 0.09 to 0.58 +/- 0.05 when in group and to 0.52 +/- 0.06 ng/ml when isolated) and prolactin (from 5.18 +/- 0.33 to 9.37 +/- 0.96 when in group and to 10.18 +/- 1.23 ng/ml when isolated) secretion, but not in terms of follicle-stimulating hormone or testosterone secretion. The most important feature observed was that in each cage there was one animal with higher ACTH levels than the other two; furthermore, the exploratory behavior of this animal was different, indicating the occurrence of almost constant higher vigilance in this animal (latency to leave the den in group: 99.17 +/- 34.95 and isolated: 675.3 +/- 145.3 s). The data indicate that in each group there is an animal in a peculiar situation and its behavior can be detected by ACTH determination in addition to behavioral performance.
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PMID:Social condition affects hormone secretion and exploratory behavior in rats. 1526 26

Altered stress responsiveness has been repeatedly related to mood and anxiety disorders. In a traditional view, a reduction of the stress response has been thought favorable. The goal of the present study was to verify the hypothesis that high anxiety is accompanied by enhanced hormone release during stress. Healthy subjects at the upper (anxious, n = 15) and lower (non-anxious, n = 12) limits of the normal range of a trait anxiety scale (State trait anxiety inventory) were exposed to psychosocial stress procedure based on public speech. Hormone levels, cardiovascular activation and skin conductance were measured. Exposure to psychosocial stress was associated with significant increases of all parameters measured. During the stress procedure, subjects with high trait anxiety exhibited lower levels of hormones of the hypothalamo-pituitary-adrenocortical axis, namely ACTH and cortisol in plasma, as well as cortisol in saliva. Similarly, the stress-induced activation of epinephrine, norepinephrine and prolactin secretion was significantly lower in anxious subjects in comparison with that in non-anxious subjects. Thus, in contrast to the traditional view, high anxiousness was not associated with exaggerated stress response. Our findings suggest that high trait anxiety may be associated with an inability to respond with adequate hormone release to acute stress stimuli.
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PMID:High trait anxiety in healthy subjects is associated with low neuroendocrine activity during psychosocial stress. 1558 60

Under acute stress conditions in the rat, there is rapid and transient increase in circulating prolactin (PRL). This leads to an elevated expression of the long form of PRLR (PRLR-L) first in the hypothalamus and the choroid plexus. This increase in PRL is involved in the inhibition of stress-induced hypocalcemia and gastric erosion. In this study we used rat PRL and a PRLR morpholino-antisense oligonucleotide to elucidate the mechanism by which hypothalamic PRLR mediates the inhibition of restraint stress in water (RSW)-induced hypocalcemia and gastric erosion. We found that this effect is largely mediated by PRLRs in the paraventricular nucleus (PVN), medial preoptic nucleus, and ventromedial hypothalamus. We also show that when measured after 7 h of RSW, microinjection of the PRLR antisense oligonucleotide into these areas down-regulates RSW-enhanced expression of PRLR-L protein in the PVN and increases the plasma PRL level, but does not affect plasma levels of another hormone, GH. Furthermore, our experiments demonstrated that under nonstress conditions, knockdown of the PRLR in the PVN significantly lowers circulating Ca2+ levels, but does not affect gastric erosion. These results suggest that PRL acting on the PRLR-L in the PVN is one of the critical pathways for regulating circulating Ca2+ levels under both acute stress and nonstress conditions.
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PMID:Prolactin receptor knockdown in the rat paraventricular nucleus by a morpholino-antisense oligonucleotide causes hypocalcemia and stress gastric erosion. 1584 20

This review focuses on research into the hormonal control of behaviors in amphibians that was conducted prior to the 21st century. Most advances in this field come from studies of a limited number of species and investigations into the hormonal mechanisms that regulate reproductive behaviors in male frogs and salamanders. From this earlier research, we highlight five main generalizations or conclusions. (1) Based on studies of vocalization behaviors in anurans, testicular androgens induce developmental changes in cartilage and muscles fibers in the larynx and thereby masculinize peripheral structures that influence the properties of advertisement calls by males. (2) Gonadal steroid hormones act to enhance reproductive behaviors in adult amphibians, but causal relationships are not as well established in amphibians as in birds and mammals. Research into the relationships between testicular androgens and male behaviors, mainly using castration/steroid treatment studies, generally supports the conclusion that androgens are necessary but not sufficient to enhance male behaviors. (3) Prolactin acts synergistically with androgens and induces reproductive development, sexual behaviors, and pheromone production. This interaction between prolactin and gonadal steroids helps to explain why androgens alone sometimes fail to stimulate amphibian behaviors. (4) Vasotocin also plays an important role and enhances specific types of behaviors in amphibians (frog calling, receptivity in female frogs, amplectic clasping in newts, and non-clasping courtship behaviors). Gonadal steroids typically act to maintain behavioral responses to vasotocin. Vasotocin modulates behavioral responses, at least in part, by acting within the brain on sensory pathways that detect sexual stimuli and on motor pathways that control behavioral responses. (5) Corticosterone acts as a potent and rapid suppressor of reproductive behaviors during periods of acute stress. These rapid stress-induced changes in behaviors use non-genomic mechanisms and membrane-associated corticosterone receptors.
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PMID:Historical perspective: Hormonal regulation of behaviors in amphibians. 1599 1

Chronic diabetes mellitus (DM) induces hyperactivity of the hypothalamo-pituitary-adrenal axis (HPA). Our present study addresses the role of vasopressin (AVP) in maintaining adrenocortical responsiveness during DM. AVP-deficient mutant Brattleboro rats were used with heterozygous controls and the V2 agonist, desmopressin was infused to replace peripheral AVP. To induce DM the rats were injected by streptozotocin (STZ, 60 mg/ml/kg i.v.) and studied 2 weeks later. The acute stress stimulus was 60 min restraint. The signs of DM (the increase in water consumption and in blood glucose levels) were discovered in all rats. The diuretic effect of the lack of AVP was additional to the DM-induced osmotic diuresis. DM induced significant, chronic stress-like somatic changes on which AVP-deficiency had no effect and although desmopressin infusion normalized the water consumption and the body weight gain in AVP-deficient rats, it had no effect on DM-induced changes. The acute stress-induced plasma ACTH elevation was smaller in AVP-deficient or DM rats but these effects were not additive. Desmopressin did not normalize the decreased ACTH-elevation of AVP-deficient animals. The resting morning plasma corticosterone level was elevated both in DM and AVP-deficient rats without interaction. The restraint-induced corticosterone rise was influenced neither by the lack of AVP nor by DM and the basal and stress-induced prolactin levels were smaller in DM rats without any effect of AVP-deficiency. In conclusion, our data suggest that AVP does not play a crucial role in HPA axis regulation during DM-induced chronic stress. In contrast, the role of AVP seems to be more important during acute stress, however, it is restricted to the ACTH regulation. According to the water consumption data diabetes insipidus seems to be an additional risk factor for DM.
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PMID:The role of vasopressin in diabetes mellitus-induced hypothalamo-pituitary-adrenal axis activation: studies in Brattleboro rats. 1646 84

Numerous reports document altered drinking behavior following acute stressors but few describe physiological responses to acute stress of chronic ethanol consuming subjects. We tested rats' responses to 120-min foot restraint immobilization (Immo) after 1 week of liquid diet containing 5% wt/vol ethanol (ethanol-fed). Controls consumed isocaloric liquid diet ad libitum (adlib-fed) or in amounts equal to that of ethanol-fed subjects on the previous day (pair-fed). Each rat was implanted with a tail artery cannula on day 7 to allow remote blood collection before and during Immo on day 8. Plasma epinephrine (Epi); norepinephrine (NE); corticosterone (Cort); prolactin (PRL); adrenomedullary gene expression of catecholamine biosynthetic enzymes tyrosine hydroxylase (TH), dopamine beta-hydroxylase (DBH), and phenylethanolamine-N-methyl transferase (PNMT); and TH protein levels were measured. Ethanol-fed rats had two to threefold higher basal plasma Epi and NE and tended to have increased Cort compared to adlib-fed or pair-fed rats. Immo increased Epi and NE in ethanol-fed rats more than twofold above those observed in controls, and also increased Cort more in ethanol-fed than in control rats. PRL was marginally affected. Ethanol potentiated the normal immobilization-induced increase in adrenomedullary TH, DBH, and PNMT messenger RNA (mRNA). TH protein increased only in ethanol-fed rats. Increased plasma catecholamine levels, adrenomedullary gene expression, and TH protein concentration in nonimmobilized ethanol-fed rats strongly suggest that ethanol consumption was itself a stressor, which potentiated the subsequent response to acute Immo. Moreover, the observed interaction of ethanol and stress on plasma catecholamine levels illustrates the importance of minimizing additional stressful stimuli when investigating ethanol's physiological effects.
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PMID:Ethanol consumption increases rat stress hormones and adrenomedullary gene expression. 1671 4

In fish, the hypothalamus-pituitary-interrenal axis (HPI-axis), the equivalent of the hypothalamus-pituitary-adrenal axis (HPA-axis) in mammals, is activated during stress and leads to production and release of cortisol by the interregnal cells in the head kidney. In mammals, the cytokine interleukin-1beta (IL-1beta) takes a key position in the innate immune and inflammatory responses and influences the HPA-axis. In fish, studies that address the effects of cytokines on HPI-axis activation are limited. We quantitatively assessed expression of IL-1beta and its receptor, IL-1RI (the latter was cloned and sequenced), in an acute restraint stress paradigm in common carp, Cyprinus carpio. We also considered expression of the pituitary hormones prolactin (PRL) and GH that have been shown to be structurally related to cytokines and have immunomodulatory actions. Pituitary PRL expression increased fourfold during stress; GH mRNA levels were unaffected. Following restraint, hypothalamic IL-1beta expression was upregulated; in head kidney and pituitary pars intermedia, IL-1RI expression significantly increased. We suggest that during acute stress IL-1beta signalling in the HPI-axis becomes more sensitive, since both ligand and receptor expressions are enhanced. In vitro, recombinant carp IL-1beta stimulates release of alpha-MSH and N-Ac beta-endorphin from the pituitary gland. This observation concurs with increased in vivo plasma levels of alpha-MSH and N-Ac beta-endorphin following restraint. Our findings combined lead us to conclude that IL-1beta affects the activity of the HPI-axis and, in turn, expression profiles of genes encoding IL-1beta and its receptor are modified during acute stress. Our study provides convincing evidence for bi-directional communication of the HPI-axis and the immune system in fish.
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PMID:Central and peripheral interleukin-1beta and interleukin-1 receptor I expression and their role in the acute stress response of common carp, Cyprinus carpio L. 1706 86

Physical or emotional stress can affect the female reproductive physiology and angiotensin II (Ang II) is a hormone that participates in the stress response and also in the control of reproductive hormones. The present study aimed at evaluating the effects of acute stress in the morning and afternoon of proestrus on sexual behavior and ovulation and the participation of Ang II in the stress-induced effects. Female rats with regular estrous cycles were used. Several different stress protocols were tested in the morning and in the afternoon of proestrus: restraint stress 10 min; restraint stress 1 h and ether stress, respectively. The participation of Ang II was evaluated by injecting Ang II receptor antagonists (losartan and PD123319) 15 min before stress. The lordosis quotient was recorded and the number of oocytes was counted. Plasma levels of luteinizing hormone, progesterone, prolactin and corticosterone were measured. All types of stress in the morning of proestrus induced a reduction in the number of oocytes. Restraint stress (1 h) in the afternoon of proestrus induced a significant reduction in the lordosis quotient. Peripheral and central losartan, but not PD123319, injections partly reverted the effects of stress on ovulation in the morning of proestrus. Acute stress in the morning of proestrus also reduced luteinizing hormone, progesterone and prolactin surges later on the same day. In conclusion, acute stress on the day of proestrus can affect female reproductive physiology. Moreover, the angiotensinergic system, through AT(1) receptors, participates in the effects of acute stress in the morning of proestrus.
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PMID:Effects of acute stress on the day of proestrus on sexual behavior and ovulation in female rats: participation of the angiotensinergic system. 1757 75

In many vertebrates, reproductive performance increases with advancing age but mechanisms involved in such a pattern remain poorly studied. One potential mechanism may be the hormonal stress response, which shifts energy investment away from reproduction and redirects it towards survival. In birds, this stress response is achieved through a release of corticosterone and is also accompanied by a decrease in circulating prolactin, a hormone involved widely in regulating parental cares. It has been predicted that, when the value of the current reproduction is high relative to the value of future reproduction and survival, as it is expected to be in older adults, the stress response should be attenuated to ensure that reproduction is not inhibited. We tested this hypothesis by measuring the corticosterone and prolactin responses of known-age (8-36 years old) incubating snow petrels (Pagadroma nivea) to a standardized capture/handling stress protocol. We also investigated whether an attenuation of the stress responses will correlate with a lower occurrence of egg neglect, a frequently observed behaviour in snow petrels. The probability of successfully fledging a chick increased from 6 years to 12 years before stabilizing after 12 years of age. Corticosterone response to stress was unaffected by age. Prolactin response to stress, however, was influenced clearly by age: in both sexes older breeders had higher stress-induced prolactin levels than younger ones. This was due to an increasing attenuation of the prolactin response to stress with advancing age in females, and in males this was due to a probably higher intrinsic capacity of older males to secrete prolactin. Moreover, higher stress-induced prolactin levels were correlated with a lower probability of neglecting the egg. In young breeders, the combination of a robust corticosterone increase with a lower ability to maintain prolactin secretion during acute stress is probably one of the functional causes of their lower incubation commitment. We suggest that the ability to maintain a threshold level of prolactin during a stressful situation may be an important physiological mechanism involved in the improvement of reproductive performance with advancing age in long-lived birds.
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PMID:Age-specific reproductive success in a long-lived bird: do older parents resist stress better? 1792 14


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