2003 Fiscal Year Final Research Report Summary
Effects of active oxygen scavengers on the occurrence of epileptic foci in a rat model of post -traumatic epilepsy
| Project/Area Number |
13671447
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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 | 大分医科大学 |
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Principal Investigator |
YOKOI Isao Oita University, Faculty of Medicine, Professor, 医学部, 教授 (80150366)
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| Co-Investigator(Kenkyū-buntansha) |
KUBOTA Hideaki Kagawa Prefectural College of Health Science, Faculty of Health Science, Lecturer, 保健医療学部, 講師 (00321266)
KITANO Takaaki Oita University, Faculty of Medicine, Associate Professor, 医学部, 助教授 (20211196)
YAMADA Naoko (NISIMARU Naoko) Oita University, Faculty of Medicine, Associate Professor, 医学部, 助教授 (60101086)
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| Project Period (FY) |
2001 – 2003
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| Keywords | posttraumatic epilepsy model / epileptic EEG / prevention of epileptic foci formation / hemoglobin / hydroxyl radical scavengers / melatonin / zinisamide / ascorbyl radical |
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| Research Abstract |
Head injury results in extravasation of blood and breakdown of red blood cells and hemoglobin (Hb). Iron liberated from Hb, and Hb itself also, is to be associated with generation of free radicals (FRs). FRs have been demonstrated to be involved in the mechanism of seizures induced by iron ion injection into the rat brain, an experimental animal model for posttraumatic epilepsy (PTE). In this study, FRs formation in the brain during convulsions and effects of FRs scavengers, such as melatonin and zonisamide (ZNS), on the occurrence of epileptogenic foci formation were examined. An experimental model for PTE was made by [lb injection into the rat brain. Experimental results were as follows :
1.The typical ascorbyl radical (Asc-R) signal was detected clearly in the hippocampal slices, and increased during kainate-induced seizures. Antiepileptic ZNS inhibited significantly the occurrence of convulsions and generation of Asc -R.
2.We developed a more specific and economical detecting method of Asc -R.
3.Positive poly-spikes were started in electrocorticograms (ECoG) of rat.3 days after Hb injection with twitching of vibrissae synchronized with spike activity.
4.The percent induction of epileptic discharges in ECoGs was not changed in rats given ZNS-contained diet for 2 months after Hb injection. Daily intake of ZNS-contained diet was significantly lower.
5.Rats were given melatonin in drinking water for 3 months after [lb injection. However, the percent induction of epileptic discharges was not changed. There were some rats showed transient weight loss.
This is the first observation of Asc-R in the brain induced by seizures with an ESR spectrometry, and Asc-R was increased in the hippocamps during kainate-induced seizures, suggesting an excess generation of FRs in the brain. However, we failed to show the effects of antioxidants on epileptic focus formation because of unexpected low diet intake and transient weight loss
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