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| 2. |
- Carlsson, S, et al.
(författare)
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Evidence for an adrenergic innervation of the adrenal cortical blood vessels in rats.
- 1993
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Ingår i: Acta physiologica Scandinavica. - 0001-6772. ; 149:1, s. 23-30
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate the blood flow in the adrenal cortex of the rat. Relative changes in the adrenal cortical blood flow were continuously measured by Laser Doppler flowmetry in 33 chloralose-anaesthetized artificially ventilated rats during electrical stimulation (1 ms, 5 V) of the left great splanchnic nerve (LGSN), which conveys both pre- and post-ganglionic nerve fibres to the adrenal gland. Laser Doppler flux (LDF) was decreased and regional resistance (RR) was increased by augmenting nerve stimulation at increasingly higher frequencies (2, 4, 8, 20 and 40 Hz). The decrease in LDF, when compared to pre-drug stimulations at 4 Hz was partially or totally inhibited by the adrenergic blocking agents trimethaphan (TRIM), guanethidine (GUA) and alpha 1-blockade with prazosin (PRAZ). Furthermore, both the decrease in LDF and the increase in RR were either completely or partially blocked by stimulation at 40 Hz after TRIM-treatment and GUA-treatment. It is concluded that the adrenal cortex in the rat is innervated by post-ganglionic adrenergic nerve fibres, which are involved in the regulation of blood flow in the adrenal cortex.
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| 3. |
- Gerber, M, et al.
(författare)
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Concerns regarding hair cortisol as a biomarker of chronic stress in exercise and sport science
- 2012
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Ingår i: Journal of Sports Science and Medicine. - 1303-2968. ; 11, s. 571-581
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Forskningsöversikt (refereegranskat)abstract
- Hair cortisol has the potential to fill the methodological void of long-term cortisol assessment while becoming a widely accepted measure in biopsychology. This review critically examines the applicability and relevance of hair cortisol measurement specifically within the field of exercise and sport science. Current measures of the HPA axis only cover a brief time period, whereas hair cortisol is a unique, non-invasive means to capture long-term cortisol secretion. Studies have shown that individuals who have elevated cortisol secretion (e.g. due to diseases associated with a disturbed activation of the HPA axis or exposure to stressful life events) reveal increased hair cortisol. By contrast, only weak correlations exist between hair cortisol and perceived stress, and the direction of the relationship between hair cortisol levels and mental disorders is unclear. Acute exercise, however, results in increased levels of cortisol that eventually is reflected in higher levels of cortisol in hair samples and studies have shown that exercise intensity is related to hair cortisol level. Thus, elevated hair cortisol levels found among regular exercisers are not necessarily pathological. Thus, one should practice caution when associating athletes’ elevated hair cortisol with poor mental health or disease. Hair cortisol analysis can contribute to a more complete understanding of how long-term cortisol elevation mediates stress-related effects on the health and performance of recreational exercisers and elite athletes. Nevertheless, it is crucial for exercise and sport scientists to consider whether their research questions can be adequately addressed, given that regular intense exercise results in substantially augmented hair cortisol levels.
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| 4. |
- Glise, Katarina, 1982-, et al.
(författare)
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Self-reported exhaustion: a possible indicator of reduced work ability and increased risk of sickness absence among human service workers.
- 2009
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Ingår i: International archives of occupational and environmental health. - 1432-1246.
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The aim of this study was to assess the construct and predictive validity of a new instrument for self-rating of stress-related Exhaustion Disorder (s-ED). METHODS: Public healthcare workers and social insurance officers, 85% females, were included (N = 2,683) in a longitudinal study. The s-ED instrument, based on clinical criteria for Exhaustion Disorder, was used at baseline to classify participants into three categories: non-s-ED, light/moderate s-ED and pronounced s-ED. Other assessments include burnout, anxiety, depression and work ability. Sick leave at follow-up after 2 years was defined as 14 days of ongoing sick leave (SA14) or a period of 60 days of sick leave during the last 12 months (SA60). Associations at baseline were expressed as prevalence ratios, and adjusted relative risks (RR) were calculated using Cox regression. RESULTS: At baseline, 16% reported s-ED. Scores of depression, anxiety and burnout and the rate of poor work ability increased with increasing severity of s-ED. Self-reported exhaustion at baseline increased the risk of reporting sickness absence at follow-up; pronounced s-ED RR 2.7; CI 1.8-4.0 for SA14 and RR 3.4; CI 2.3-5.2 for SA60. CONCLUSIONS: Self-rated ED corresponded well to established scales for mental health, indicating sufficient construct validity. Individuals reporting s-ED at baseline were more likely to report sickness absence at follow-up, confirming its predictive properties. The s-ED instrument may be a useful tool for occupational health services in identifying human service workers at risk of having or developing a potentially disabling stress-related mental illness.
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| 5. |
- Hägg Samuelsson, Ulrika, 1973-, et al.
(författare)
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Gene expression profile and aortic vessel distensibility in voluntarily exercised spontaneously hypertensive rats: potential role of heat shock proteins
- 2005
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Ingår i: Physiological Genomics. - 1094-8341. ; 11:22:2, s. 319
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Tidskriftsartikel (refereegranskat)abstract
- Physical exercise is considered to be beneficial for cardiovascular health. Nevertheless, the underlying specific molecular mechanisms still remain unexplored. In this study, we aimed to investigate the effects of voluntary exercise on vascular mechanical properties and gene regulation patterns in spontaneously hypertensive rats. By using ultrasound biomicroscopy in an ex vivo perfusion chamber, we studied the distensibility of the thoracic aorta. Furthermore, exercise-induced gene regulation was studied in aortae, using microarray analysis and validated with real-time PCR. We found that distensibility was significantly improved in aortas from exercising compared with control rats (P < 0.0001). Exercising rats demonstrated a striking pattern of coordinated downregulation of genes belonging to the heat shock protein family. In conclusion, voluntary exercise leads to improved vessel wall distensibility and reduced gene expression of heat shock protein 60 and 70, which may indicate decreased oxidative stress in the aortic vascular wall.
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| 6. |
- Hägg Samuelsson, Ulrika, 1973-, et al.
(författare)
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Voluntary physical exercise and coronary flow velocity reserve: a transthoracic colour Doppler echocardiography study in spontaneously hypertensive rats
- 2005
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Ingår i: Clin Sci (Lond). - 0143-5221. ; 109:3, s. 325-34
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Tidskriftsartikel (refereegranskat)abstract
- In the present study, we have developed and demonstrated a coronary artery imaging protocol in rats using transthoracic high-frequency CDE (colour Doppler echocardiography) to investigate the potential direct effects of exercise on CFVR (coronary flow velocity reserve). SHR (spontaneously hypertensive rats) performed voluntary exercise for 6 weeks. Rats were then submitted to ultrasonographic examination and CFVR measurements. The LAD (left anterior descending coronary artery) was visualized using transthoracic CDE in a modified parasternal long-axis view. Doppler measurement was made in mid-LAD during baseline and adenosine-induced hyperaemic condition. Gene and protein expression in cardiac tissue were studied using real-time PCR and immunohistochemistry. Adenosine infusion significantly (P<0.001, as determined by ANOVA) decreased HR, without affecting blood pressure in anaesthetized SHR. A significantly greater adenosine dose-dependent response was seen in exercised rats compared with controls (P=0.02, as determined by ANOVA). The baseline flow velocity in mid-LAD was 0.33+/-0.06 and 0.41+/-0.14 m/s in the exercised and control animals respectively (P value was not significant). The maximum adenosine-induced response was reached at a dose of 140 microg.kg-1 of body weight.min-1, and CFVR averaged at 2.6+/-0.53 and 1.5+/-0.24 in exercised and control animals respectively (P<0.01). Gene expression of CuZnSOD was up-regulated by 21% in exercised animals compared with controls (1.1+/-0.16 compared with 0.89+/-0.09; P<0.01), whereas eNOS expression was unchanged. In conclusion, CFVR in rats can be non-invasively assessed using CDE with high feasibility. Physical exercise is associated with improved CFVR and antioxidative capacity in SHR.
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| 7. |
- Hägg Samuelsson, Ulrika, 1973-, et al.
(författare)
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Voluntary physical exercise-induced vascular effects in spontaneously hypertensive rats
- 2004
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Ingår i: Clin Sci (Lond). - 0143-5221. ; 107:6, s. 571-81
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Tidskriftsartikel (refereegranskat)abstract
- Forced training has been shown to have beneficial vascular effects in various animal exercise models. In the present study, we explored possible physiological and molecular effects of voluntary physical exercise on various vascular beds. SHR (spontaneously hypertensive rats) performed voluntary exercise for 5 weeks in a computerized wheel cage facility. Ex vivo myograph studies revealed an increased sensitivity of the ACh (acetylcholine)-mediated vasodilation in resistance arteries of the exercised animals (ED50=15.0+/-3.5 nmol/l) compared with the controls (ED50=37.0+/-8.8 nmol/l; P=0.05). The exercise/control difference was abolished after scavenging reactive oxygen radicals. In conduit arteries, ACh induced a similar vasodilatory response in both groups. The in vivo aortic wall stiffness, assessed by means of Doppler tissue echography, was significantly lower in the exercising animals than in controls. This was demonstrated by significantly increased peak systolic aortic wall velocity (P=0.03) and the velocity time integral (P=0.01) in exercising animals compared with controls. The relative gene expression of eNOS (endothelial nitric oxide synthase) was similar in both groups of animals, whereas Cu/ZnSOD (copper/zinc superoxide dismutase) gene expression was significantly increased (+111%; P=0.0007) in the exercising animal compared with controls. In conclusion, voluntary physical exercise differentially improves vascular function in various vascular beds. Increased vascular compliance and antioxidative capacity may contribute to the atheroprotective effects associated with physical exercise in conduit vessels.
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| 8. |
- Jonsdottir, Ingibjörg H, 1966-, et al.
(författare)
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A prospective study of leisure-time physical activity and mental health in Swedish health care workers and social insurance officers
- 2010
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Ingår i: Preventive Medicine. - 0091-7435. ; 51:5, s. 373-377
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: This study analyzes longitudinal associations between self-reported leisure-time physical activity (PA) and perceived stress, burnout and symptoms of depression and anxiety. METHOD: Cohort data collected in 2004 and 2006 from health care and social insurance workers in western Sweden (2694 women; 420 men) were analyzed. Cox regression was conducted to examine associations between baseline levels of PA and mental health (MH) problems 2 years later. RESULTS: Cross-sectional analysis show that individuals reporting either light physical activity (LPA) or moderate-to-vigorous physical activity (MVPA) were less likely to report high levels of perceived stress, burnout and symptoms of depression and anxiety, as compared to individuals reporting a sedentary lifestyle. The risks of symptoms of depression, burnout, and high stress levels at follow-up were significantly lower for those reporting LPA or MVPA at baseline. For symptoms of anxiety, an activity level corresponding to MVPA was required. CONCLUSION: Participation in PA appeared to lower the risk of developing MH problems two years later. This relationship involved LPA and MVPA regarding feelings of depression, burnout and perceived stress, and exclusively MVPA regarding feelings of anxiety. The implications of these findings are important, as preventive strategies for psychosocial stress and mental health problems are needed.
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| 9. |
- Jonsdottir, Ingibjörg H, 1966-, et al.
(författare)
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Acute mental stress but not enforced muscle activity transiently increases natural cytotoxicity in spontaneously hypertensive rats.
- 1996
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Ingår i: Acta physiologica Scandinavica. - 0001-6772. ; 157:4, s. 443-9
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Tidskriftsartikel (refereegranskat)abstract
- The influence of acute mental stress and the effect of electrically induced skeletal muscle contractions on natural cytotoxicity in vivo was investigated in spontaneously hypertensive rats Natural cytotoxicity in vivo was measured as the clearance of injected 51Cr-labelled YAC-1 lymphoma cells from the lungs, which are specifically lysed by natural killer cells. The mental stress consisted of an air jet directed towards the animals in their cage for 25 min. During the mental stress there was a significant increase in natural cytotoxicity. Thus, retained radioactivity in the lungs was decreased to 74 +/- 6% of the control levels which was set to 100% (P < 0.01). This augmentation of YAC-1-cell clearance could be blocked with the beta-adrenergic receptor antagonist Timolol. Two hours after termination of the air stress, in vivo cytotoxicity had returned to control levels. In contrast, acute physical stress, consisting of electrically induced muscle contractions for 60 min, had no significant effects on in vivo cytotoxicity, either during the stimulation or 1, 2 or 24 h after the stimulation. Further, significantly increased plasma levels of adrenaline were seen after the air jet stress, but not after muscle stimulation. There were no significant changes in plasma noradrenaline levels either after air stress or muscle stimulation. These results indicate that changes in in vivo cytotoxicity after mild mental stress are dependent on increased plasma catecholamine levels while acute physical stress without changes in catecholamine levels, does not influence in vivo cytotoxicity.
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| 10. |
- Jonsdottir, Ingibjörg H, 1966-, et al.
(författare)
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Chronic intracerebroventricular administration of beta-endorphin augments natural killer cell cytotoxicity in rats.
- 1996
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Ingår i: Regulatory peptides. - 0167-0115. ; 62:2-3, s. 113-8
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Tidskriftsartikel (refereegranskat)abstract
- We have studied the effect of chronic intracerebroventricular (i.c.v.) infusion of different opioid peptides on natural killer (NK) cell mediated cytotoxicity in vivo in the spontaneously hypertensive rat (SHR). The in vivo NK cell activity was measured as the clearance of 51Cr-labelled YAC-l lymphoma cells from the lung tissues. Further, the phenotype of lymphocytes in spleen and peripheral blood was analysed by flow cytometry (FACS). All opioid drugs were administered i.c.v. for 6 days with osmotic minipumps releasing 1.0 microliter/h. beta-Endorphin (10 or 20 micrograms/rat per day) significantly increased NK cell cytotoxicity in vivo. The opioid receptor antagonist naloxone (10 mg/kg, i.p.) given immediately before the injection of YAC-lymphoma cells, completely abolished the effects of i.c.v. administered beta-endorphin. Corresponding doses of beta-endorphin administered subcutaneously (s.c.) with minipumps for 6 days did not significantly affect NK cell cytotoxicity. Neither Leu- or Met-enkephalin (20 micrograms/rat per day) nor dynorphin (20 micrograms/rat per day) administered i.c.v. had any significant effects on NK cell activity. In beta-endorphin treated SHR, the percentage of cells with NK cell phenotype (OX52+/CD5-) in peripheral blood was not significantly different from that of controls, while the percentage of cells with T cell phenotype (CD5+/OX52-) was significantly decreased. The percentage of splenic NK cells (OX52+/CD5-) and T cells (CD5+/OX52-) was also unchanged by beta-endorphin treatment i.c.v. These results suggest that of the opioid peptides administered i.c.v., only beta-endorphin augments in vivo NK cell mediated cytotoxicity. We thus conclude that these effects most probably are centrally and opioid receptor mediated effects, since beta-endorphin in the same dose administered peripherally does not influence in vivo NK cell cytotoxicity.
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