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- 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: Physiol Genomics. - 1531-2267 .- 1094-8341. ; 22:3, s. 319-26
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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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| 2. |
- Manni, Luigi, 1962, et al.
(författare)
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Effect of exercise on ovarian morphology and expression of nerve growth factor and alpha(1)- and beta(2)-adrenergic receptors in rats with steroid-induced polycystic ovaries
- 2005
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Ingår i: J Neuroendocrinol. ; 17:12, s. 846-58
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Tidskriftsartikel (refereegranskat)abstract
- Oestadiol valerate (EV)-induced polycystic ovaries (PCO) in rats cause anovulation and cystic ovarian morphology. Denervation of ovarian sympathetic nerves restores ovulatory disruption. In the present study, we determined whether 5 weeks of voluntary exercise influence ovarian morphology and the expression of sympathetic markers in the EV-induced PCO rat model. The effect of exercise on (i) ovarian morphology; (ii) mRNA and protein expression of nerve growth factor (NGF); and (iii) mRNA and number of ovarian-expressing cells for the NGF receptor (p75 neurotrophin receptor) and the alpha(1a)-, alpha(1b)-, alpha(1d)- and beta(2)-adrenergic receptors (ARs) in rats with EV-induced PCO was evaluated. PCO was induced by a single i.m. injection of EV, and controls were injected with oil alone in adult cycling rats. The rats were divided into four groups: (i) control (oil); (ii) exercise group (oil + exercise); (iii) a PCO group (EV); and (iv) a PCO exercise group (EV + exercise). The exercise and PCO exercise groups ran voluntarily for 5 weeks in computer-monitored wheels placed in the cages where they were housed. The results obtained indicated that ovarian morphology was almost normalised in the PCO exercise group; NGF mRNA and protein concentrations were normalised in the PCO exercise group; high numbers of NGF receptor expressing cells in PCO ovaries were lowered by exercise; and the number of immunopositive cells of the different AR subtypes were all reduced after exercise in the PCO group, except for the alpha(1b)- and beta(2)-AR whereas the mRNA levels were unaffected, indicating transcriptional regulation. In conclusion, our data indicate a beneficial effect of regular exercise, as a modulator of ovarian sympathetic innervation, in the prevention and treatment of human PCOS.
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| 3. |
- Naylor, Andrew Stuart, 1977
(författare)
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Differential effects of voluntary running on hippocampal plasticity in the adult rat brain
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The continuation of neuronal birth from dividing neural stem cells in the dentate gyrus of the hippocampus throughout adulthood is known to play an important role in maintaining normal hippocampal function, such as memory and learning. Negative alterations in the levels of adult neurogenesis have also been linked to several neurodegenerative diseases, including Alzheimer s disease and mood disorders such as depression. This thesis investigated the effects of varying durations of voluntary running on the proliferation and differentiation of newborn cells in the hippocampus and the regulatory mechanisms involved in running induced hippocampal plasticity in adult rats. Animals were allowed free access to running wheels for 9, 24 or 43 days. On the last two days of voluntary running, bromodeoxyuridine was administered to label new cells and then the animals were sacrificed immediately or four weeks later to measure progenitor proliferation or levels of neurogenesis. We also used a hippocampal-dependent task, the Morris water maze, to measure possible alterations in spatial memory. Moderate levels of voluntary running for nine days were found to significantly increase progenitor proliferation and neurogenesis by almost 500% compared to non-running rats. We found that these effects were regulated through endogenous opioids and that phosphorylated CREB was involved in the running induced effects. Four weeks after the cessation of moderate levels of voluntary running, large pool of new neurons was generated with improvements seen in spatial memory. In contrast, high levels of voluntary running for 24 days were found to decrease progenitor proliferation levels compared to non-running rats. In these animals, we found a concomitant increase in corticosterone levels, an increased adrenal gland size and a decreased thymus size, indicating high levels of a response to stress. These negative effects were prevented by restricting daily running distances to more moderate levels over the 24 days. Interestingly, un-restricted long-term running increased progenitor survival with a small increase in neurogenesis and no effects seen on spatial memory compared to non-running rats. Extended running for 43 days was found to normalise progenitor proliferation, despite indications of a chronic response to stress. In these rats, we found increased levels of brain derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) in the hippocampus and frontal cortex, which may be an important part of a compensatory mechanism during periods of stress to maintain homeostasis in the brain. These findings demonstrate that moderate levels of voluntary running are most beneficial in promoting increased levels of neurogenesis in the brain and improving hippocampal function. There also exists an innate compensatory mechanism within the brain to attempt to restore homeostasis under periods of stress.
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| 4. |
- Naylor, Andrew Stuart, 1977, et al.
(författare)
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Extended voluntary running inhibits exercise-induced adult hippocampal progenitor proliferation in the spontaneously hypertensive rat.
- 2005
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Ingår i: Journal of neurophysiology. - : American Physiological Society. - 0022-3077 .- 1522-1598. ; 93:5, s. 2406-14
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Tidskriftsartikel (refereegranskat)abstract
- Previous work has shown that voluntary running increases cell proliferation and neurogenesis in the dentate gyrus of the adult hippocampus. Here we report that long-term running for 24 days results in a down-regulation of hippocampal progenitor proliferation to one-half the level of nonrunning controls compared with a fivefold increase in progenitor proliferation seen after 9 days of voluntary running (short-term running). The negative effects seen on proliferation after 24 days of running were prevented by restricting daily running distances (by 30-50%) during 24 days. Long-term running for 24 days increases the response of the hypothalamic-pituitary-adrenal axis, with an increase in adrenal gland weight and increased plasma corticosterone levels, as well as decreased thymus weight, indicating a stress response as a possible mediator of decreased progenitor proliferation. Furthermore, the negative effects seen on the observed stress response after 24 days of running were prevented by restricting daily running distance. Short-term running did not alter these stress parameters compared with nonrunning controls. However, it increased phosphorylated cyclic AMP response element binding protein (pCREB) in the dentate gyrus, an increase that was not seen in nonrunning controls or after 24 days of running. Taken together, these data suggest that voluntary running does not always enhance proliferation and that the decrease in progenitor proliferation seen in long-term running is possibly mediated by mechanisms involving a stress response in the animal. However, a moderate level of long-term running was able to prevent the negative stress-related changes seen in unrestricted long-term running.
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