| Project/Area Number |
60570698
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Orthopaedic surgery
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| Research Institution | Ehime Univercity |
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Principal Investigator |
NOJIMA Motoo Ehime University Professor, 医学部, 教授 (60035384)
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| Co-Investigator(Kenkyū-buntansha) |
井関 満永 愛媛大学, 医学部, 助手 (90136325)
角 典洋 愛媛大学, 医学部附属病院, 助手 (80163054)
SUTO Takashi Ehime University Instructor, 医学部附属病院, 講師 (20116940)
KOMURO Terumasa Ehime University Associate Professor, 医学部, 助教授 (20037386)
SUMI Michihiro Ehime University Assistant
ISEKI MITSUNAGA Ehime University Assistant
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| Project Period (FY) |
1985 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1986: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1985: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | Neuromuscular junction / Slow twitch fibers / 神経切断 |
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| Research Abstract |
A: The morphological changes of the neuromuscular junctions (NMJs) caused by nerve transection have been examined by scanning electron microscopy in the peroneus longus muscle of the Chinese hamster. After denervation, the grooves become shallower with lower sarcoplasmic ridges, and the subsynaptic area of the muscle fibers gradually flattens. The subsynaptic area shows a plate-like sarcoplasmic elevation by 4 weeks and persists as a fusiform focal bulge on the atrophied muscle fiber after 4 weeks. Concurrently the subsynaptic folds decrease in number and transform into shallow pit-like invaginations. Any subsynaptic specialization has not been discernible after 16 weeks.
B: The differences of NMJs between different muscle fibers had been examined with scanning electron microscopy and analyzed morphometrically. The extensor digitorum longus and soleus and soleus muscles in the rat were also compared. The former consisted mostly of fast twitch fibers whereas the latter consisted of slow twitch fibers (75%) and fast twitch fibers (25%). NMJs of slow twitch fiber was small and the subsynaptic folds had sparse, narrow slit-like and pit-like openings. NMJs of fast twitch fiber was large and the subsynaptic folds had numerous, wide and slit-like openings.
C: The differences of subneural apparatuses at NMJs in the extensor digitorum longus muscle between normal and dystrophic (mdx) mice were examined. In the first 14 postnatal days in the normal mice, primitive cup-like synaptic trough had developed to anastomosing grooves containing both pit-like and slit like junctional folds. At the 35th day, the apparatuses attained almost adult form. In mdx mice at the 14th day, the apparatuses had showed transformation similar to those in the normal mice. At the 35 th day, pit-like openings still existed in a large proportion. The results suggest that the subsynaptic apparatuses of neuromuscular junctions in mdx mice show an immature form compared to that in normal mice.
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