1999 Fiscal Year Final Research Report Summary
Development of the method(s) to monitor cardiovascular function and its intracellular signal transduction
| Project/Area Number |
09557005
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
General physiology
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| Research Institution | Yamaguchi University |
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Principal Investigator |
KOBAYASHI Sei Yamaguchi University, School of Medicine, Professor, 医学部, 教授 (80225515)
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| Co-Investigator(Kenkyū-buntansha) |
KODAMA Yuka Carl Zeiss, Microscopy Department, Researcher, 研究員
TODOROKI Natsuko (轟 奈津子) Yamaguchi University, School of Medicine, Research Associate,, 医学部, 助手 (90253153)
MOGAMI Kimiko Yamaguchi University, School of Medicine, Research Associate, 医学部, 助手 (80263771)
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| Project Period (FY) |
1997 – 1999
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| Keywords | Signal Transduction / Cytosolic Celcium Ion / Endothelial Cells / Ryo-kinase / Sphingolipids / Vascular Smooth Muscle |
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| Research Abstract |
The following results were obtained :
1. FIRST YEAR : We developed the method to monitor cardiovascular function and its intracellular signal transduction. We introduced rapidly recombinant proteins into the cytosol of vascular smooth muscle strips, using the receptor-coupled membrane permeabilization. Using this new system, we identified Rho-kinase as a novel messenger for the CaィイD12+ィエD1-independent contraction of vascular smooth muscle. This conclusion was supported by the following results.
1)Recombinant catalytic domain of Rho-kinase is constitutively active and induced the CaィイD12+ィエD1-independent contraction of permeabilized vascular smooth muscle in the absence of cytosolic GTE. 2) Rho-kanase-induced contraction was associated with the elevation of myosin light chain phosphorylation. 3) Rho-kinase-induced contraction and increase in the myosin light chain phoshorylation were resistant to a myosin light chain kinase blocker.
2. SECOND YEAR : We investigated signal transduction fro
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m the cell membrane to cytosolic messenger (Rho-kinase). We identified several sphingolipids as a novel mediator for the CaィイD12+ィエD1-independent contraction of vascluar smooth muscle. In addition, we found that the sphingolipids induces CaィイD12+ィエD1-independent contraction in the absence of cytosolic GTP in permeabilized vascular smooth muscle strips, which was blocked by a Rho-kinase inhibitor, suggesting that sphingolipid-induced contraction is mediated by Rho-kinase. Fluorometry of fura-2 revealed that sphingolipids induced large contraction without elevation of cytosolic CaィイD12+ィエD1 concentration ([CaィイD12+ィエD1]i) in cerebral arteries, supporting the role of sphingolipid as a mediator for the CaィイD12+ィエD1-independent contraction.
3. THIRD TEAR : We started to investigate the CaィイD12+ィエD1-independent contraction of human vascular smooth muscle strips. Sphingolipid induced very small contraction obtained from patients whose cholesterol levels are normal, but induced large contraction of the strips obtained from patients whose cholesterol levels are high. These finding suggest that a sphingolipid/Rho-kinase pathway plays an important role in the development of abnormal vascular contraction which was frequently associated with hyperlipidemia. Less
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