1995 Fiscal Year Final Research Report Summary
Reconstruction of CNS network as a system
| Project/Area Number |
05454680
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
神経・脳内生理学
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
KAWAGUCHI Saburo Kyoto Univ.Sch.of Med., Dept.Integrative Brain Sci., Prof., 医学研究所, 教授 (70024635)
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| Project Period (FY) |
1993 – 1995
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| Keywords | CNS reconstruction / Axonal regeneration / Corticospinal tract / Rubrospinal tract / Spinal cord injury / 機能回復 |
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| Research Abstract |
Regenerative potential of the mammalian central nervous system (CNS) was studied with two types of experimentation : transection of the spinal cord pathway and transplantation of embryonic CNS structures. The results of the first experimentation are follows. 1) Marked regeneration of corticospinal and rubrospinal tracts occurred spontaneously after transection in the rat up to 25 days of age. 2)This occurrence was highly reproducible when transection was made so sharply that no edema was produced in the lesion. 3) Blunt transection resulted in abortive regeneration with gliosis, scarring, and cavity formation. 4) Regenerated tracts were functionally active when tested electrophysiologically. 5) Behavior of the animals with marked regeneration was hardly distinguishable from normal. The results of the second experimentation are follows. 1) Spinal cord segments of neonatal rats were replaceable with embryonic homologous structures. 2) Replacement was successful only when the graft was pl
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aced in the normal orientation. 3) Neural connections similar to normal were formed between the lumbar enlargement and the upper brain structures across the replaced segments. 4) Such connections were functionally active when tested electrophysiologically. 5) The animals with replaced spinal cord segments walked, ran, and climbed with nearly normal hind-forelimb coordination. These results led the following conclusion. 1) It appears likely that robust outgrowth of axons across the lesion occurs without. restriction when organization of positional and guiding cues for axons was maintained in the axonal environment despite transection or it was provided by embryonic homologous structures. 2) In contrast to the widely held view that the mammalian CNS lacks regenerative capacity, it has an incredible potential for regrowth and self-organization, which makes it possible to reconsruct functionally significant neural connections similar to normal. Curing the spinal cord-injured may not be an impossible dream. Less
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