1990 Fiscal Year Final Research Report Summary
Studies on the Molecular Mechanism of Neuromuscular Junction Formation
| Project/Area Number |
01480523
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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 |
物質生物化学
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| Research Institution | Brain Research Institute, Niigata University (1990)
Kyoto University (1989) |
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Principal Investigator |
MISHINA Masayoshi Niigata University Brain Research Institute, Department of Neuropharmacolgy, Professor, 脳研究所, 教授 (80144351)
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| Project Period (FY) |
1989 – 1990
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| Keywords | Acetylcholine Receptor / Neuromuscular Junction / Myoblast / Primary Culture / Differentiation / alphabetadelta-AChR / gamma-subunit / alpha-subunit |
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| Research Abstract |
We have previously shown that the replacement of the gamma-subunit by the epsilon-subunit is responsible for the functional alteration of the acetylcholine receptor during muscle development. In an attempt to establish an in vitro system in which the switch of the acetylcholine receptor subunits takes place, myogenic cells lines (L6 and C2C12) and primary culture of myoblasts were tested for expression of the acetylcholine receptor subunits during differentiation. The alpha-, beta-, gamma-and delta-subunit mRNAs increased prominently during development from myoblasts to myotubes, whereas the epsilon-subunit was detected only in late stage of the development of the primary cultured cells, but not in the cell lines.
The acetylcholine receptor expressed in Xenopus oocytes injected with the bovine alpha-, beta- and delta-subunit-specific mRNAs (referred to as alphabetadelta-AChR) is unusual in that its channel opens spontaneously at a high frequency in the absence of agonist. Thus, the gamma-and epsilon-subunits are important for stabilizing the closed state of the unliganded receptor channel. Furthermore, the mean channel open time of acetylcholine-activated alphabetadelta-AChR is considerably longer than that of the complete receptors containing either the gamma- or epsilon-subunit. The ease with which it is assembled raises the possibility that the alphabetadelta-AChR contributes to some of the variation in receptor properties that occur during development.
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[Publications] Fukuda, K., Kubo, T., Maeda, A., Akida, I., Bujo, H., Nakai, J., Mishina, M., Higashida, H., Neher, E., Marty, A. &Numa, S.: "Selective effector coupling of muscarinic acetylcholine receptor subtypes." Trends Pharmacol. Sci.10. 4-10 (1989)
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[Publications] Jackson, M. B., Imoto, K., Mishina, M., Konno, T., Numa, S. & Sakmann, B.: "Spontaneous and agonist-induced openings of an acetylcholine receptor channel composed of bovine muscle alpha-, beta-and delta-subunits." Pflugers Arch.417. 129-135 (1990)
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「研究成果報告書概要(欧文)」より
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[Publications] Sakimura, K., Bujo, H., Kushiya, E., Araki, K., Yamazaki, M., Yamazaki, M., Meguro, H., Warashina, A., Numa, S. & Mishina, M.: "Functional expression from cloned cDNAs of glutamate receptor species responsive to kainate and quisqualate." FEBS Lett. 272. 73-80 (1990)
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「研究成果報告書概要(欧文)」より
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[Publications] Mishina, M., Sakimura, K., Kushiya, E., Araki, K., Yamazaki, M., Yamazaki, M. & Meguro, H.: "Structure and function of acetylcholine and glutamate receptors." Fidia Research Foundation Symposium. 8.
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「研究成果報告書概要(欧文)」より
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[Publications] Konno, T., Busch, C., Sakmann, B., Imoto, K., Wang, F., Nakai, J., Mishina, M. & Numa, S.: "Structural determinants of ion selectivity in the acetylcholine receptor channel." Proc. R. Soc. Lond.
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