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

The effects of handling, ether vapor anesthesia and blood sampling on serum LH and prolactin were determined in intact, castrate and dexamethasone-treated male rats. Cage removal and transport to an adjacent room increased LH and prolactin levels by 10 and 15 min after the initial animal disturbance. Intact male rats subjected to repeated ether anesthesia and blood sampling showed a more rapid increase in serum LH and prolactin than the preceding rats, since serum LH and prolactin was increased by 4, 8 and 15 min after initial cage disturbance. In a group of rats subjected to serial blood sampling over a longer time interval, both prolactin and LH levels remained higher than 90 min after initial animal handling. At 90 minutes after a single blood sampling, blood prolactin concentration remained higher than in controls. Serum LH levels returned to control levels 90 min after the stress of a single blood sampling. Although serum prolactin was increased in the castrate group subjected to serial anesthesia and blood sampling, LH concentrations were reduced under the same conditions. Injection of 5 and 50 mug of dexamethasone/100 g body wt for 8 days markedly reduced adrenocortical responsiveness to the stress of serial anesthesia and blood sampling at 1, 4, 8 and 15 min after initial rat disturbance. The 50 mug dexamethasone treatment reduced the stress-stimulated increase in serum prolactin at all blood sampling intervals. The dexamethasone-treated groups also showed smaller increases in serum LH at 8 and 15 min after first animal handling than the control rats. These results indicate that serum LH and prolactin concentrations are consistently increased by acute stress in intact male rats, the duration of the stress stimulation of LH and prolactin is at least 90 min under the conditions of this study, serum LH levels of castrate male rats are decreased by acute stress and dexamethasone administration lowers stress stimulation of LH and prolactin release.
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PMID:Effects of acute stress on serum LH and prolactin in intact, castrate and dexamethasone-treated male rats. 110 6

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

Core temperature of the spontaneously hypertensive rat (SHR) was not found to be different from the core temperature of the control rat, the Wistar-Kyoto rat (WKY), when the rats were left undisturbed in their home cages. When the rats were exposed to a variety of stressful environments, including cage switching, exposure to an open field, and handling, both SHR and WKY rats showed an increase in temperature. For the set of rats supplied by Charles River, the SHR temperature response to the stress was identical to the WKY rats' temperature response. For the set of rats supplied by Taconic Farms, the SHR was found to have a greater temperature response to the acute stress and the open-field stress. The Taconic Farms rats were also exposed to restraint stress, which resulted in a rise in temperature that was greater for the SHR when compared with the WKY. Because we have observed the increased lability in body temperature of the SHR compared with the WKY rats during restraint, we believe that it is important that studies with these strains of rat be done using minimal or no restraint.
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PMID:Temperature regulation in biotelemetered spontaneously hypertensive rats. 233 Oct 25

Sympathetic-adrenal medullary responses to acute footshock stress were assessed in inbred Dahl salt-sensitive (S/JR) and salt-resistant (R/JR) rats by measuring plasma levels of norepinephrine (NE) and epinephrine (EPI). Ten-week-old S/JR and R/JR rats were surgically prepared with indwelling tail artery catheters which permitted direct measurements of mean arterial pressure (MAP, mmHg) and heart rate (HR, beats/min) and remote sampling of blood. Two days after surgery, S/JR and R/JR rats were subjected to an acute stress paradigm. Blood samples were collected before and 3 minutes after transfer of rats to a shock chamber, after 1 minute of intermittent footshock, and again 5 minutes later. S/JR rats had significantly higher resting MAP's compared to R/JR rats. In contrast, baseline heart rates were similar for rats of the two strains. Basal plasma levels of NE and EPI were also similar in S/JR and R/JR rats. Upon transfer from the home cage to a shock chamber, S/JR rats exhibited significant increases in plasma levels of both catecholamines, while R/JR rats maintained circulating levels of NE and EPI that were near baseline values. However, S/JR and R/JR rats had similar increments in plasma NE and EPI following acute footshock stress. Five minutes after footshock, levels of NE and EPI returned toward baseline values for R/JR's, but remained significantly elevated above baseline in hypertensive S/JR rats. These data suggest that S/JR rats are more responsive than R/JR controls to the mild stress of transfer, but exhibit comparable responses to the more intense stress of inescapable footshock.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Sympathetic-adrenal medullary responses to acute stress in Dahl hypertensive (S/JR) rats. 272 39

The effects of crowding on thyrotropin (TSH) and somatotropin (GH) secretion were studied in two-month-old male rats. Crowded rats (9-10 per cage) showed lower serum GH levels than controls (3 per cage). Likewise, serum GH was lower in crowded rats after acute exposure to stress. However, percentage inhibition of GH secretion induced by acute stress was similar in crowded and control rats. Crowding reduced the TSH response to acute stress. The results found with the administration of hypothalamic regulatory factors suggest that the impaired GH and TSH secretion observed in crowded rats was not likely to be at the pituitary level. Therefore, altered neuroendocrine control of GH and TSH secretion appears to exist in crowded rats. Preliminary results obtained in rats crowded from weaning to adulthood suggest that food restriction only partially accounts for the changes observed in crowded rats.
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PMID:Crowding-induced changes in basal and stress levels of thyrotropin and somatotropin in male rats. 312 Jun 86

The effect of specific stressful stimuli on neuropeptide levels was studied in rat brain regions known to be involved in the mediation of stress responses and anxiety. Rats were sequentially removed, one by one with 20-min intervals from group cages and immediately decapitated. A selective increase of the somatostatin level was observed in the amygdala in the rats taken for sacrifice second last and last, compared to the rats taken earlier from the respective group cage (increases by 40 to 69%, p < 0.05 or p < 0.01). Isolation of rats in single cages for 24 h or 1 week before sacrifice, increased the substance P level in the dorsal periaqueductal grey by 26 and 27% (p < 0.05 in both cases), respectively, compared to group housed rats. In group housed rats treated with diazepam (5 mg/kg, s.c.) 140 min before sacrifice, the level of substance P in the rostral hippocampus and dorsal periaqueductal grey was reduced by 40% (p < 0.001) and 28% (p < 0.05), respectively, compared to saline treated controls. In conclusion, handling, as well as a single dose of the anxiolytic drug diazepam, appears to induce rapid, selective and region-specific changes of regional brain peptide levels in the rat. The effects of handling are likely to be related to the acute stress response and are probably not secondary to increased plasma glucocorticoid levels.
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PMID:Effects of sequential removal of rats from a group cage, and of individual housing of rats, on substance P, cholecystokinin and somatostatin levels in the periaqueductal grey and limbic regions. 751 54

The purpose of this study was to examine the effect of differential housing on humoral immunity following exposure to an acute stressor. Forty male Sprague-Dawley adult rats were randomly assigned to either a singly housed or group-housed (five rats/cage) condition. Approximately 2 weeks after the start of the study, all animals were immunized with 1 ml of a 10% suspension of sheep red blood cells (SRBC) in saline. After the injections, half of the animals from each housing condition were subjected to an acute stressor (forced swim, 60 min/day for 3-5 days). Animals exposed to the acute stressor displayed adrenal gland hypertrophy and reduced thymus and spleen weights compared to the unstressed (control) animals. Both behavioral stimuli (housing and forced swim) demonstrated no effect on antibody production to SRBC. However, singly housed animals showed an increase in lymphocyte percentage, and corticosterone and glucose levels regardless of subsequent exposure to acute stress. Within a treatment condition, there were no significant correlations between the immune and endocrine measures. It was concluded that reduced social contact (i.e., individual housing) with subsequent exposure to an acute stressor does not appear to inhibit immunological responsiveness to an antigen.
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PMID:Impact of differential housing on humoral immunity following exposure to an acute stressor in rats. 777 98

Previous studies have shown that fetal ethanol exposure (FEE) may have long-term effects on the function of catecholaminergic neurons in different regions of the CNS. The present study is the first to examine the effects of FEE on regional brain catecholamine responses following acute stress (a single 60-min restraint stress), repeated stress (single periods of restraint stress on 1, 5, or 10 consecutive days), and recovery from stress (recovery for up to 60 min in the home cage following a single 60-min period of restraint stress). Both male and female offspring from FEE, pair-fed (PF), and ad libitum-fed control (C) groups were tested in adulthood to determine catecholamine content in the cortex, hypothalamus, and hippocampus. A single period of restraint reduced cortical norepinephrine (NE) content in FEE and PF animals compared with that in the cortex of C animals, and reduced hypothalamic NE content in FEE female offspring below that found in animals in all other groups. In contrast, hippocampal NE content was higher in FEE than in C animals following a single period of restraint; PF animals had intermediate levels of hippocampal NE and did not differ significantly from either FEE or C animals. Following repeated periods of restraint, cortical NE content was lower in FEE than in C animals; PF animals once again had intermediate levels of NE. Importantly, basal (nonstressed) NE content did not differ among groups in any brain area examined. In addition, several significant changes in regional brain catecholaminergic responses to acute stress were observed in animals across all treatment groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Prenatal ethanol exposure: changes in regional brain catecholamine content following stress. 822 1

Intense acute stress, consequent to restraint, leads to a diminished production of IgE antiovalbumin antibodies in mice. The IgE content of sera from experimental or control animals was assayed by the enzyme-linked immunosorbent assay (ELISA) at days 8, 16, and 20 after immunization. The statistics revealed significant differences in the IgE level of the animals submitted to acute stress and home cage control animals on days 16 and 20 after immunization, but not on day 8.
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PMID:Influence of stress on IgE production. 844 8

Neuroendocrine correlates of chronic stress in human infants have not been established. The goal of the present study was to create an animal model of continuous chronic stress using the immature rat to measure basal plasma corticosterone, and secretion of plasma corticosterone in response to an acute stress. This was achieved by modulation of the cage environment for rat pups and their mothers. During postnatal days 2-9, pups were maintained in three groups: (1) handled, (2) not handled and with ample bedding; and (3) not handled with limited bedding. On postnatal day 9, some pups from each group were subjected to acute cold-separation stress and were killed 90, 240, or 360 min later along with unstressed controls. The group not handled and with limited bedding manifested increased plasma corticosterone output even without cold exposure and a sustained increase of plasma corticosterone after cold-separation stress. Plasma corticosterone interanimal variability was increased and body weight was decreased in these pups, typical of a state of chronic stress. The first model of continuous stress in infant rats in which upregulation of hypothalamic-pituitary-adrenal axis is achieved without maternal separation is presented. This paradigm may more closely approximate the human situation of chronically stressed, neglected infants.
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PMID:Abnormal corticosterone regulation in an immature rat model of continuous chronic stress. 888 44


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