Intracellular Ca<SUP>2+</SUP> stores and vascular smooth muscle contraction
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- IINO Masamitsu
- Department of Pharmacology, Faculty of Medicine, The University of Tokyo
Bibliographic Information
- Other Title
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- 細胞内Ca<SUP>2+</SUP>ストアと血管平滑筋収縮
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Abstract
The Ca2+ release activity of inositol 1, 4, 5-trisphosphate receptor (InsP3R) is biphasically dependent on the cytoplasmic Ca2+ concentration: activation near 100 nM and inhibition around 1 μM. We have found that the cytoplasmic Ca2+ concentration is not simply a modulator of InsP3R but is an indispensable factor for channel activation. The Ca2+ requirement of InsP3R places the Ca2+ release channel within a Ca2+-mediated positive feedback loop, which has been demonstrated with caged InsP3 and Ca2+. The positive feedback mechanism seems to be the important basis for the generation of Ca2+ wave in various cell types including smooth muscle cells. To further clarify the role of Ca2+ stores in the smooth muscle function, we measured the Ca2+ concentration in individual smooth muscle cells in isolated vascular tissues stimulated with perivascular sympathetic nerves using a confocal microscope. We observed in these cells Ca2+ waves/oscillations due to Ca2+ release from the stores. These results show that the Ca2+ requirement of InsP3 receptor plays an important role in the regulation of vascular contraction. They also throw new light on both pharmacological and pathophysiological studies of vascular tone.
Journal
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- Folia Pharmacologica Japonica
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Folia Pharmacologica Japonica 106 (supplement), 41-44, 1995
The Japanese Pharmacological Society
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Details 詳細情報について
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- CRID
- 1390282679247528960
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- NII Article ID
- 10008631231
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- NII Book ID
- AN00198335
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- ISSN
- 13478397
- 00155691
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- Text Lang
- ja
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- Data Source
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- JaLC
- Crossref
- CiNii Articles
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- Abstract License Flag
- Disallowed