2002 Fiscal Year Final Research Report Summary
REDUCTION OF FUNCTIONAL GABA_A RECEPTOR EXPRESSION IN THE NEOCORTEX OF EL MICE
| Project/Area Number |
13670681
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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 |
Neurology
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| Research Institution | University of Occupational and Environmental Health |
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Principal Investigator |
YUHI Tomoaki University of Occupational and Environmental Health, School of Medicine, Research Associate, 医学部, 助手 (60330982)
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| Co-Investigator(Kenkyū-buntansha) |
UENO Susumu University of Occupational and Environmental Health, School of Medicine, Research Assistant Professor, 医学部, 講師 (00279324)
FUETA Yukiko University of Occupational and Environmental Health, School of health sciences, Research Associate, 産業保健学部, 助手 (10132482)
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| Project Period (FY) |
2001 – 2002
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| Keywords | El mice / GABA_A receptor / Xenopus oocytes / gene expression / messengerRNA / neocortex slices / α1 subunit / bicuculline |
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| Research Abstract |
There is extensive evidence indicating a crucial role for γ-aminobutyric acid (GABA) in epileptogenesis. The El (epilepsy-like) mouse is an epilepsy model developed from the ddY mouse and is very susceptible to seizure. El mice have been found to exhibit a decrease in GABA-mediated inhibition. However, previous studies remained nuclear about relationship between the GABA receptor function and epileptogenesis. In the present study, we investigated the GABA_A receptor gene expression and function in the neocortex of unstimulated El mice and ddY control mice (18-20 weeks old).
1) Northern blot analysis showed 30% decrease in GABA_A receptor α1 subunit messenger RNA (mRNA) level in El mice, compared to ddY mice. On the other hand, β2 and γ2 subunit mRNA levels did not show any significant differences.
2) GABA_A receptor functions were analyzed by the measurement of GABA-induced currents using Xenopus oocytes expression system. The maximal GABA-induced currents obtained from oocytes injected with neocortex mRNA of El mice, were significantly smaller than those obtained from oocytes injected with mRNA of ddY mice.
3) Extracellular recordings from the neocortex slices using single-pulse configuration showed significant difference in the GABA_A receptor antagonist (bicuculline: BMI and picrotoxin:PTX)-induced changes of field significant decrease in the BMI and PTX-induced changes of the amplitude of field potentials in El(-) mice.
These results suggest that, in the neocortex of El(-) mice, there is a decrease in GABA_A receptor expression and recurrent GABAergic inhibition, which may be related to the epileptogenesis in the El strain.
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Research Products
(4 results)
