2001 Fiscal Year Final Research Report Summary
Molecular Pharmacology of Capacitative Ca^<2+> Entry Channel of Human Aortic Endothelial Cell
| Project/Area Number |
12670080
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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 pharmacology
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| Research Institution | Akita University |
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Principal Investigator |
IIJIMA Toshihiko Akita University School of Medicine, Professor, 医学部, 教授 (30004724)
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| Co-Investigator(Kenkyū-buntansha) |
SATOH Eisaku Akita University School of Medicine, Research Associate, 医学部, 助手 (10282162)
YAZAWA Kazuto Akita University School of Medicine, Lecturer, 医学部, 講師 (90212274)
ONO Kyoichi Akita University School of Medicine, Associate Professor, 医学部, 助教授 (70185635)
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| Project Period (FY) |
2000 – 2001
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| Keywords | human aortic endothelial cells / voltage clamp / intracellular Ca^<2+> concentration / Ca^<2+> ATPase / antisense / capacitative Ca^<2+> entry / Cl^- channel / TRPC4 |
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| Research Abstract |
In vascular endothelial cells, intracellular Ca^<2+> concentration ([Ca^<2+>]_i) increases in response to various vasoactive substances and mechanical stimulation, causing synthesis and release of endothelial active molecules.
In this study, 1) human aortic endothelial cells were treated with antisense oligodeoxynucleotides targeting the 5' translation start site of the human membrane Ca^<2+> ATPase isoform 1. Results provide the evidence of functional role of plasma membrane Ca^<2+> ATPase, although other mechanisms including Na^+/Ca^<2+> exchange may play the primary role in regulating [Ca^<2+>]i.
2) To examine the functional relationship between the increase in [Ca^<2+>]i and the Cl^- current, we investigated the effects of mibefradil on [Ca^<2+>]i and the Cl^- current increased by histamine in human aortic endothelial cells. Mibefradil decrease the histamine-induced [Ca^<2+>]i elevation and Cl^- current in a concentration-dependent manner. Those results indicate, the functional relationship between the capacitative Ca^<2+> entry channel and the Cl^- channel.
And, 3) we isolated three (α, β, γ) TRPC4 variants, thought to be candidates for the molecular basis of capacitative Ca^<2+> entry channels, from rat brain cDNA using RT-PCR. In HEK-293 cells, basal [Ca^<2+>]i was increased, but carbachol or thapsigargin-induced Ca^<2+> entry were not affected by expression of rTRPC4α. Results indicate that rTRPC4α is functionally involved in the regulation of basal Ca^<2+> levels when transiently expressed in HEK-293 cells and may need intracellular factors for acting as the capacitative Ca^<2+> entry channel.
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