| Project/Area Number |
02454121
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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 |
Neurophysiology and muscle physiology
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
KAWAGUCHI Saburo Dept. Integ. Brain Sci., Fac. Med., Kyoto Univ., Associate Prof., 医学部, 助教授 (70024635)
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| Project Period (FY) |
1990 – 1992
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| Project Status |
Completed (Fiscal Year 1992)
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| Budget Amount *help |
¥5,100,000 (Direct Cost: ¥5,100,000)
Fiscal Year 1992: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1991: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1990: ¥3,900,000 (Direct Cost: ¥3,900,000)
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| Keywords | Spinal cord injury / Spinal cord grafting / Cerebellar grafting / Regeneration of CNS pathway / Reconstruction of CNS circuitries / Functional recovery / 神経回路の再構築 / 小脳核 / 小脳前核 / 小脳遠心投射 / 小脳求心投射 / 中枢神経伝導路の再構築 / 軸索新生 |
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| Research Abstract |
In contrast to the current concept that regeneration of the mammalian CNS axons is very limited and has no functional significance, the present studies revealed that marked, functionally significant regeneration of CNS axons occurred after complete transection of the spinal cord in the rat and that either the cerebellum or the spinal cord segments in neonatal rats were replaceable.
1)Spinal Cord Regeneration The spinal cord of neonatal rats was transected completely at a level of the lower thoracic segments. One to two months after transection, neural connections beyond the transection were examined by retrograde labeling with fluorescence dyes injected into the lumber enlargement or the upper cervical segments. In the animals operated on before 18 days post partum, the descending and ascending pathways traversed the site of transection were indistinguishable from normal. Locomotor function of these animals was also indistinguishable from normal.
2)Replacement of the Cerebellum The whole
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cerebellum or hemicerebellum of neonatal rats was replaced with embryonic homologous structures. Homotopically grown grafts became as large as the normal cerebellum exhibiting normal cytoarchitecture and formed input and output connections indistingusihable from normal. The grafts, thus, appeared to have established neural integrity with the host brain in a manner very similar to normal ontogenesis.
3)Replacement of the Spinal Cord The lower thoracic segments of the neonatal rats were replaced with embryonic homologous structures. The grafted embryonic spinal cord segments grew and united with the host spinal cord at both the rostral and caudal stumps to form a seamless spinal cord. Anterograde and retrograde labeling with tracer demonstrated that neural connections hardly distinguishable from normal were formed between the lumber enlargement and upper brain structures traversing the graft. These animals walked, ran, and climbed with coordination of fore- and hindlimbs in a manner strikingly similar to normal. Less
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