2002 Fiscal Year Final Research Report Summary
The expression of apoptosis neurogenesis and axonal sprouting in epileptitogenic focus
| Project/Area Number |
12671342
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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 |
Cerebral neurosurgery
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| Research Institution | Chiba University |
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Principal Investigator |
MINE Seiichiro Chiba University, University Hospital, Lecturer, 医学部附属病院, 講師 (70190709)
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| Co-Investigator(Kenkyū-buntansha) |
MURAI Hisayuki Chiba University, University Hospital, Assistant, 医学部附属病院, 助手 (80241967)
YAMAURA Akira Chiba University, Graduate School of Medicine, professor, 大学院・医学研究院, 教授 (40009717)
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| Project Period (FY) |
2000 – 2002
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| Keywords | Kindling / Neurogenesis / Bromodeoxyuridine / PSA-NCAM |
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| Research Abstract |
The purpose of this research was to verify the hypothesis that reconstruction of nervous system by adult neurogenesis and addition of new neuronal circuits contributed to acquisition and maintenance of epileptogenesis. We examined the changes in the hippocampus of amygdaloid kindled rats by the immunohistochemical detection of bromodeoxyuridine (BrdU) labeled proliferating cells and polycialylated neural cell adhesion molecule (PSA-NCAM), the marker of newly generated granule cells and mossy fibers.
BrdU labeled cells in the basal layer of dentate granule cells increased significantly in the kindling group compared with the control group (four to six fold). PSA-NCAM positive cells in the granule cell layer also increased significantly in the kindling group (about two fold) by confocal laser scanning microscopy. PSA-NCAM immunoreactivity in the stratum lucidum of CA3 was enhanced by 50-120% in the kindling group by comparing the numbers of PSA-NCAM positive spots on the confocal laser scanning microscopic images. Significant differences were not seen between the side ipsilateral and contralateral to the electrode placement through these examinations. Immunoelectron microscopic study revealed the increase of PSA-NCAM positive mossy fibers and terminals in the stratum lucidum of the CA3a subfield in the kindling group. Strongly PSA-NCAM positive, irregularly shaped, and elongated terminals were seen frequently in the kindling group.
These findings indicate that adult neurogenesis in the dentate granule cell layer and projection of newly formed mossy fibers to the stratum lucidum of CA3 with synaptic rearrangement are enhanced by kindling. These changes are supposed to alter the excitability of the hippocampal neuronal circuits and influence many various connecting regions. Such alternation may contribute to the acquisition and the maintenance of epileptogenesis in kindling.
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