2004 Fiscal Year Final Research Report Summary
Relationship between ultrastructural profiles of membrane systems involved in excitation-contraction coupling and signal transduction in skeletal muscle cells following exercise training
| Project/Area Number |
14380019
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
体育学
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| Research Institution | National Institute of Fitness and Sports in Kanoya |
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Principal Investigator |
TAKEKURA Hiroaki National Institute of Fitness and Sports in Kanoya, Sports Performance, Professor, 体育学部, 教授 (00206963)
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| Co-Investigator(Kenkyū-buntansha) |
KASUGA Norikatsu Aichi University of Education, Physical Education, Professor, 教育学部, 教授 (60152659)
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| Project Period (FY) |
2002 – 2004
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| Keywords | exercise / membrane system / excitation contraction coupling / skeletal muscle / signal transduction / immunohistochemistry / electron microscope |
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| Research Abstract |
The t-tubules and SR are structurally and functionally joined at Ca^<2+> release units(CRUs), known as triads. We have studied the effects of short term denervation followed by reinnervation on the ultrastructural architectures in CRUs of fast-twitch(FT) and slow-twitch(ST) muscle fibers. Ischiadic nerve freezing resulted in total lack of neuromuscular transmission for 3 days followed by a slow recovery, but no decline in twitch force elicited by direct stimulation. The latter measurements indicate no significant atrophy within this time frame. The membrane systems of skeletal muscle fibres were visualized using a high voltage electron microscope. [^3H]nitrendipine binding was used to detect levels of dihydropyridine receptor(DHPR) expression. The Ca^<2+> pumping free sarcoplasmic reticulum domains were not affected by the denervation, but the Ca^<2+> release domains were dramatically increased, particularly in the FT fibres. The increase is evidenced by a doubling up of the areas of contacts between SR and t-tubules, so that in place of the normal triadic arrangement, pentadic and heptadic junctions, formed by multiple interacting layers of ST and t-tubules are seen. Frequency of pentads and heptads increases and declines in parallel to the denervation and reinnervation but with a delay. Immunofluorecence and electron microscopy observations show presence of DHPR and ryanodine receptor clusters at pentads and heptads junctions. A significant positive correlation between the level of [^3H]nitrendipine binding component and the frequency pentads and heptads was observed in both the FT and ST fibres indicating that overexpression of DHPRs accompanies the build up extra junctional contacts. It is possible that the multiple sites of pentad and heptad formation appear in response to muscle disuse to compensate for the normal CRUs, thus acting to increase the released Ca^<2+> for muscular contraction from the SR.
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Research Products
(16 results)
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[Journal Article] Differential contribution of skeletal and cardiac II-III loop sequences to the assembly of DHP-receptor arrays in skeletal muscle.2004
Author(s)
Takekura, H., Paoini, C., Franzini-Armstrong, C., Kugler, G., Grabner, M., Flucher, B.E.
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Journal Title
Mol.Biol.Cell 15
Pages: 5408-5419
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Changes in localization and orientation of triads following selective elimination of cytoskeletal protein in rat skinned muscle fiber.2004
Author(s)
McGrath, K., Nishizawa, T., Yamashita, S., Tamaki, H., Saito, K., Takekura, H.
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Journal Title
Ann.Fitness Sports Sci. 32
Pages: 1-9
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Differences in electromyographic behavior of the synergistic muscles during prolonged isometric contractions at different loads(in Japanese).2004
Author(s)
Tamaki, H., Kitada, K., Kirimoto, H., Wagatsuma, A., Ogita, F., Takekura, H., Shibayama, H.
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Journal Title
Jpn.J.Physiol.Anthropol. 9
Pages: 53-58
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Alterations of trabecular architecture in the proximal tibia after denervation in rats.2003
Author(s)
Tamaki, H., Kotake, N., Yamamoto, A., Wagatsuma, A., Ogita, F., Takekura, H.
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Journal Title
Adv.Exercise Sports Physiology 9
Pages: 211
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Age-related differences in the effect of running training on cardiac myosin isozyme compostoin in rats.2002
Author(s)
Machida, S., Tsujimoto, H., Suzuki, H., Kasuga, N., Kobayashi, K., Narusawa, M.
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Journal Title
J.Gerontol. : Biological Sciences 57A
Pages: B339-B343
Description
「研究成果報告書概要(欧文)」より
