| Project/Area Number |
61480311
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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 |
Cerebral neurosurgery
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| Research Institution | Nagasaki University |
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Principal Investigator |
MORI Kazuo Professor, Nagasaki University School of Medicine, 医学部, 教授 (50025540)
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| Co-Investigator(Kenkyū-buntansha) |
KAMINOGO Makio Instructor, Nagasaki University School of Medicine, 医学部, 助手 (40145256)
ISHIZAKI Hiroaki Instructor, Nagasaki University School of Medicine, 医学部, 助手 (60136679)
ONO Kenji Associate Professor, Nagasaki University School of Medicine, 医学部, 助教授 (60112372)
BABA Hiroshi Instructor, Nagasaki University School of Medicine, 医学部, 助手 (20133176)
河野 輝昭 長崎大学, 医学部, 講師 (70112373)
三宅 仁志 長崎大学, 医学部, 助手 (30175616)
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| Project Period (FY) |
1986 – 1988
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥6,500,000 (Direct Cost: ¥6,500,000)
Fiscal Year 1988: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1987: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1986: ¥3,500,000 (Direct Cost: ¥3,500,000)
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| Keywords | Intractable epilepsy / Premotor cortex / Caudate nucleus / Caudate stimulation / Motor cortex / キンドリング / in vivo dialysis / 実験てんかん / 皮質低頻度刺激 / ペニシリン焦点 / DA / DOPAC / GABA / 5-HT / 低頻度持続刺激 / feedback刺激 |
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| Research Abstract |
Roles of the caudate nucleus in seizure developments from the motor or premotor cortical foci were studied in experimental models of epilepsy. In chronic rats, continuous electrical stimulation with 8-10 Hz to the premotor cortex induced electroclinical seizures which were divided into 4 stages. Electrocoagulation or microinjection of muscimol (GABA agonist) to the ipsilateral caudate nucleus increased a stimulus threshold necessary to induce each seizure stage. Seizure developments of the premotor cortical kindling in rats were significantly suppressed following the ipsilateral caudate lesion. On the other hand, numbers of interictal spikes induced by application of penicillin to the motor cortex in acute cats were significantly decreased under the feedback stimulation (10 Hz) to the ipsilateral caudate nucleus. However, feedback caudate mucate stimulation did not modify full-blown sustained paroxysms.
Electrophysiological studies suggest that striato-nigro-thalamic circuits are composed-of two successive inhibitory links (GABAergic). Also, there exist powerful caudate-thalamic inhibitory pathways. Observed inhibitory effect following lesion of, or muscimol injection to the caudate nucleus may be due to disruption of this caudate-nigral inhibitory loop in which nigro-thalamic inhibition becomes more powerful. Inhibitory effects of feedback stimulation to the caudate nucleus on interictal cortical spikes may results from the latter circuit. These findings suggest that a functions of the caudate nucleus might be changeable according to various states of seizure.
Our preliminary study with in vivo microdialysis showed that measurements of extracellular neurotransmitters in the caudate nucleus during various seizure stage may be worthwhile.
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