1997 Fiscal Year Final Research Report Summary
Roles of the plasma membrane in Ca^<2+> oscillations in smooth muscle cells
| Project/Area Number |
08660361
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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 |
Basic veterinary science/Basic zootechnical science
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| Research Institution | Gifu University |
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Principal Investigator |
KOMORI Seiichi Gifu Univ., Faculty of Agriculture, Professor, 農学部, 教授 (70195866)
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| Co-Investigator(Kenkyū-buntansha) |
UNNO Toshihiro Gifu Univ., Faculty of Agriculture, Research Associate, 農学部, 助手 (90252121)
OHASHI Hidenori Gifu Univ., Faculty of Agriculture, Professor, 農学部, 教授 (40001531)
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| Project Period (FY) |
1996 – 1997
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| Keywords | Smooth muscle / Muscarinic receptor / Calcium release / Calcium store / Calcium oscillations / Inositol trisphosphate / G protein |
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| Research Abstract |
The present study was made to elucidate the role of the plasma membrane and intracelullar Ca^<2+> stores in oscillations in cytosolic Ca^<2+> concentration following stimulation of muscarinic receptors in single smooth muscle cells of guinea-pig ileum.
1. The muscarinic receptor-mediated Ca^<2+> oscillations occur differentially because of Ca^<2+> influx across the plasma membrane associated with action potential discharge and of Ca^<2+> release from internal stores by a second messenger, inositol trisphosphate.
2. Ca^<2+> store-derived Ca^<2+> oscillations require a sustained Ca^<2+> influx for their persistence and regulation of the oscillation frequency. The L-type of Ca^<2+> channel and an as yet unidentified Ca^<2+> channel may be involved in the sustained Ca^<2+> influx.
3. The plasma membrane-derived type of Ca^<2+> oscillation may have no or little contribution from Ca^<2+>-induced Ca^<2+> release ; Ca^<2+> entering the cell during action potential discharge activtes ryanodine-sensitive, Ca^<2+>-gated Ca^<2+> channels in the internal store to release Ca^<2+> from there.
4. During generation of Ca^<2+> store-derived Ca^<2+> oscillations, membrane potential oscillates coincidentally in time with them. The membrane potential oscillations result each from potentiation of the activity of muscarinic receptor-operated nonselective cation channels by a rise in cytosolic Ca^<2+> concentration.
The results of no.1,2 and 3 have been published in international technical journals and those of no.4 are under submission.
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