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- Wyckelsma, VL, et al.
(författare)
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Vitamin C and E Treatment Blocks Changes in Kynurenine Metabolism Triggered by Three Weeks of Sprint Interval Training in Recreationally Active Elderly Humans
- 2021
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Ingår i: Antioxidants (Basel, Switzerland). - : MDPI AG. - 2076-3921. ; 10:9
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Tidskriftsartikel (refereegranskat)abstract
- The kynurenine pathway (KP) is gaining attention in several clinical fields. Recent studies show that physical exercise offers a therapeutic way to improve ratios of neurotoxic to neuroprotective KP metabolites. Antioxidant supplementation can blunt beneficial responses to physical exercise. We here studied the effects of endurance training in the form of sprint interval training (SIT; three sessions of 4–6 × 30 s cycling sprints per week for three weeks) in elderly (~65 years) men exposed to either placebo (n = 9) or the antioxidants vitamin C (1 g/day) and E (235 mg/day) (n = 11). Blood samples and muscle biopsies were taken under resting conditions in association with the first (untrained state) and last (trained state) SIT sessions. In the placebo group, the blood plasma level of the neurotoxic quinolinic acid was lower (~30%) and the neuroprotective kynurenic acid to quinolinic acid ratio was higher (~50%) in the trained than in the untrained state. Moreover, muscle biopsies showed a training-induced increase in kynurenine aminotransferase (KAT) III in the placebo group. All these training effects were absent in the vitamin-treated group. In conclusion, KP metabolism was shifted towards neuroprotection after three weeks of SIT in elderly men and this shift was blocked by antioxidant treatment.
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| 5. |
- Glenmark, B, et al.
(författare)
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Difference in skeletal muscle function in males vs. females: role of estrogen receptor-beta
- 2004
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Ingår i: American journal of physiology. Endocrinology and metabolism. - : American Physiological Society. - 0193-1849 .- 1522-1555. ; 287:6, s. E1125-E1131
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Tidskriftsartikel (refereegranskat)abstract
- Male skeletal muscles are generally faster and have higher maximum power output than female muscles. Conversely, during repeated contractions, female muscles are generally more fatigue resistant and recover faster. We studied the role of estrogen receptor-β (ERβ) in this gender difference by comparing contractile function of soleus (mainly slow-twitch) and extensor digitorum longus (fast-twitch) muscles isolated from ERβ-deficient (ERβ−/−) and wild-type mice of both sexes. Results showed generally shorter contraction and relaxation times in male compared with female muscles, and ERβ deficiency had no effect on this. Fatigue (induced by repeated tetanic contractions) and recovery of female muscles were not affected by ERβ deficiency. However, male ERβ−/− muscles were slightly more fatigue resistant and produced higher forces during the recovery period than wild-type male muscles. In fact, female muscles and male ERβ−/− muscles displayed markedly better recovery than male wild-type muscles. Gene screening of male soleus muscles showed 25 genes that were differently expressed in ERβ−/− and wild-type mice. Five of these genes were selected for further analysis: muscle ankyrin repeat protein-2, muscle LIM protein, calsequestrin, parvalbumin, and aquaporin-1. Expression of these genes showed a similar general pattern: increased expression in male and decreased expression in female ERβ−/− muscles. In conclusion, ERβ deficiency results in increased performance during fatigue and recovery of male muscles, whereas female muscles are not affected. Improved contractile performance of male ERβ−/− mouse muscles was associated with increased expression of mRNAs encoding important muscle proteins.
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| 7. |
- Holmberg, K, et al.
(författare)
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Generation and phenotypic characterization of a galanin overexpressing mouse
- 2005
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Ingår i: Neuroscience. - : Elsevier BV. - 0306-4522 .- 1873-7544. ; 133:1, s. 59-77
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Tidskriftsartikel (refereegranskat)abstract
- In most parts of the peripheral nervous system galanin is expressed at very low levels. To further understand the functional role of galanin, a mouse overexpressing galanin under the platelet-derived growth factor-B was generated, and high levels of galanin expression were observed in several peripheral tissues and spinal cord. Thus, a large proportion of neurons in autonomic and sensory ganglia were galanin-positive, as were most spinal motor neurons. Strong galanin-like immunoreactivity was also seen in nerve terminals in the corresponding target tissues, including skin, blood vessels, sweat and salivary glands, motor end-plates and the gray matter of the spinal cord. In transgenic superior cervical ganglia around half of all neuron profiles expressed galanin mRNA but axotomy did not cause a further increase, even if mRNA levels were increased in individual neurons. In transgenic dorsal root ganglia galanin mRNA was detected in around two thirds of all neuron profiles, including large ones, and after axotomy the percentage of galanin neuron profiles was similar in overexpressing and wild type mice. Axotomy reduced the total number of DRG neurons less in overexpressing than in wild type mice, indicating a modest rescue effect. Aging by itself increased galanin expression in the superior cervical ganglion in wild type and transgenic mice, and in the latter also in preganglionic cholinergic neurons projecting to the superior cervical ganglion. Galanin overexpressing mice showed an attenuated plasma extravasation, an increased pain response in the formalin test, and changes in muscle physiology, but did not differ from wild type mice in sudomotor function. These findings suggest that overexpressed galanin in some tissues of these mice can be released and via a receptor-mediated action influence pathophysiological processes. © 2005 Published by Elsevier Ltd on behalf of IBRO.
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