1996 Fiscal Year Final Research Report Summary
The roles in agonist-induced morphological mechanisms in cultured human umbilical vein endothelial cells.
| Project/Area Number |
07807010
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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 |
General physiology
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| Research Institution | Tokyo Medical College |
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Principal Investigator |
HASHIGUCHI Toshio Tokyo Medical College Dept.of Physiology, Associate Professor, 医学部, 助教授 (90133363)
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| Co-Investigator(Kenkyū-buntansha) |
HASHIGUCHI Mitsuko Tokyo Medical College Dept.of Physiology, Assistant, 医学部, 助手 (30246277)
HASHIGUCHI Toshio Tokyo Medical College Dept.of Physiology, Associate Professor, 医学部, 助教授 (90133363)
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| Project Period (FY) |
1995 – 1996
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| Keywords | Human Umbilical Vein Endothelial Cells / morphometry / roundness value / histamine / protein kinase C / tyrosine kinase |
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| Research Abstract |
Vascular endothelium constitutes the inner lining of vascular wall and acts as a selective varrier to various substrates. It is also known that endothelial cells are targets of inflammatory mediators which cause various functions including an increase in vascular permeability. We investigated the roles of agonist-induced morphological changes by time-lapse analysis in cultured human umbilical vein endothelial cells using histamine as an inflammatory mediator. The mechanisms of intracellular signal transductions in inflammation were investigated by the movement of cytosolic Ca^<2+> concentrations and cytoskeletal events. Histamine induced transient shrinkage of cell periphery which coincided with loosening of cell to cell junctions. This change was abolished by promethazine, an antagonist of H^1 receptor, but not H_2 antagonist. This shrinkage was dependent upon extracellular Ca^<2+>. Histamine induced biphasic increase in [Ca^<2+>] _<in>. The first phase was transient and the second on
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e was sustained. An H_1 antagonist was effective on histamine-induced increase in cytosolic Ca^<2+>. These results suggest that histamine activates H^1 receptors. Then influx of Ca^<2+> promotes breakdown of inosytolphospholipid turnover and activation protein kinase C (PKC) which in turn phosphorylates various cellular proteins including cytoskeleton-associated proteins. Diglycerol, one of the products of phospholipid breakdown and an activator of PKC,was found to mimic morphological effect of histamine. On the other hand PMA,another PKC potentiator, induced biphasic morphological changes which is different from that of histamine. The first phase was shrinkage of cell periphery and the second one was delayd elongation of cells. The facts that only the second phase was inhibited by PKC inhibitor, tyrosine kinase inhibitor and protein synthesis inhibitor strongly suggest multiple signaling pathways are involved in histamine action. In addition to PKC activation another pathways presumably through activation of protein tyrosine kinase might play a crucial role in histamine-induced morphological change. Less
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