1989 Fiscal Year Final Research Report Summary
Studies on the axonal regeneration of the cerebellothalamic projection after transection in the cat.
| Project/Area Number |
62480107
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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 Institute for Brain Research, Faculty of Medicine, Associate Professor, 医学部, 助教授 (70024635)
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| Project Period (FY) |
1987 – 1989
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| Keywords | cerebellofugal projection / axonal regeneration / cerebellocerebral response / embryonic brain graft / fibronectin / xenograft / functional recovery |
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| Research Abstract |
The present research project aimed at finding favorable conditions under which mammalian central nervous pathways can regenerate. Experiments were performed in the cat and rat in which the decussation of the brachium conjunctivum (BCX) was transected completely and various chemicals (arabinosylcytosine, 5-fluorodeoxyuridine, substance P, norepineph rine, laminin, fibronectin) were applied into the lesion or embyonic brain tissue containing homotopic structure was grafted in the lesion.
After being raised 14-73 days postoperatively, all animals were subjected to a WGA-HRP injection into the cerebellar nuclei for the anterograde labeling of the cerebellofugal projection. In some of them cerebello cerebral responses were recorded to ascertain functional connectivity of the regenerated projection. The occurrence of regeneration of the cere bellofugal projection was demonstrated in the fibronectin-treated and embryonic brain tissue-grafted animals. The regeneration in the latter animals with homograft (from rat to rat) was so marked that the regenerated projection was hardly distinguishable from the intact one not only from morphological but also electrophysiological aspect. The embryonic brain tissue was effective even in xenograft (from rat to cat). Without chemicals or grafting, a marked regeneration of the cerebellofugal projection after transection occurred in rats only when the transection was performed before 3 days of age. In summary, a marked, functionally active regeneration of the cerebellofugal projection occurred under favorable conditions which were provided most effectively by grafting of embryonic brain tissue containing homotopic structure. It appears likely that there are cues for the induction of growing axons in ontogenesis that can be transferred to an adult brain in serving for the growth of regenerating axons. Identification of molecules in such cues remains to be studied.
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