1995 Fiscal Year Final Research Report Summary
ELECTROPHARMACOLOGYCAL ANALYSIS OF INTRACELLULAR SIGNALTRANSDUCTIONS OF VASCULAR ENDOTHERIAL CELLS
| Project/Area Number |
06670098
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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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,DEPARTMENT OF PHARMACOLOGY,PROFESSOR, 医学部, 教授 (30004724)
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| Project Period (FY) |
1994 – 1995
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| Keywords | aortic endotherial cell / intracelullaru Ca^<2+> concentration / Thapsigargin / Cyclopiazonic acid / endoplasmic Ca^<2+> ATPase / Ca^<2+> entry / Calcium influx factor (CIF) / Intracellular Ca^<2+> store |
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| Research Abstract |
In cultured vascular endothelial cells, histamine and ATP at high concentrations (>10 muM) produce an initial transient followed by sustained elevation in intracellular free Ca^<2+> concentration ([Ca^<2+>]_i). In the present experiments, mechanisms responsible for the latter sustained elevation were studied in cultured human aortic endothelial cells loaded with the fluorescent Ca^<2+> indicator fura-2. The latter phase was eliminated by removal of extracellular Ca^<2+>, and was reversibly abolished by reduction of extracellular Cl^- concentration to 40 mM or by the Cl^- channel blocker N-phenylanthranilic acid (NPA,1 mM). Effects of thapsigargin and cyclopiazonic acid (CPA), specific inhibitors of endoplasmic reticulum Ca^<2+>-ATPase, on [Ca^<2+>]_i were also examined. Thapsigargin (1-1000 nM) and CPA (0.1-100 muM) produced a biphasic change in [Ca^<2+>]_i. The slow declining phase was eliminated by removal of extracellular Ca^<2+> and was prevented by the low Cl^- condition and NPA.These results suggest that the sustained elevation of [Ca^<2+>]_i in response to histamine, ATP,thapsigargin and CPA is produced by the Cl^--sensitive entry of extracellular Ca^<2+> activated by the rise in [Ca^<2+>]_i and/or by the depletion of intracellular Ca^<2+> stores in cultured human aortic endothelial cells.
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