2002 Fiscal Year Final Research Report Summary
Age related functional and morphological alterations in rat diaphragm and phrenic motoneuron
| Project/Area Number |
12680035
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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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 | Yamaguchi University |
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Principal Investigator |
MIYATA Hirofumi Professor, Biological Sciences, Yamaguchi Univ., 農学部, 教授 (90190793)
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| Co-Investigator(Kenkyū-buntansha) |
WADA Naomi Professor, Veterinary Medicine, Yamaguchi Univ., 農学部, 教授 (20210982)
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| Project Period (FY) |
2000 – 2002
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| Keywords | Rat / Phrenic motoneuron / Diaphragm / Muscle fiber / Rheobase / Input resistance / Specific force / Contraction speed |
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| Research Abstract |
No significant differences were found in all parameters in recruited phrenic motoneuron, while the rheobase of the non-recruited motoneurons was significantly lower in the 2-year group than the other two groups. The mean interval of action potentials of the recruited motoneurons was longer in the 1- and 2-year groups than the 10-week group, and the firing pattern in 2-year group was considerably irregular. Although there were no significant differences in the twitch tension among the groups, tetanus tensions by high frequency stimulation (20-100Hz) were significantly lower in the older group. The time to peak tension and half relaxation time were significantly longer in aged diaphragm muscles. The histochemical profiles of aged diaphragm muscle showed a smaller area of FG fibers and higher percentage of SO fibers.
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