| Project/Area Number |
11660290
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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 |
Basic veterinary science/Basic zootechnical science
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
OHTA Toshio Hokkaido Univ. Grade.School of Vet.Med., Asso.Prof., 大学院・獣医学研究科, 助教授 (20176895)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2000: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1999: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Keywords | chromaffin cells / exocytosis / whole-cell patch-clamp / tyrosine kinases / ATP / internal Ca stores / 副腎クロム親和性細胞 / アデニンヌクレオチド / エキソサイトーシス / カテコールアミン / 細胞内ストア / パッチクランプ / 細胞内カルシウム / カフェイン / チロシンキナーゼ阻害薬 / ムスカリン受容体 |
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| Research Abstract |
In this project, I analyzed membrane currents, intracellular Ca concentration ([Ca2+]i) and catecholamine (CA) secretion from isolated adrenal chromaffin cells to identify the functional roles of internal Ca stores and the store-dependent Ca entry mechanisms. A simultaneous on-line system for measurement of CA and ATP was made using culture cells. 1) In voltage-clamped chromaffin cells, Ca released from internal stores produced a transient [Ca2+]i increase concomitant with a transient outward K current. 2) In Ca-free conditions, [Ca2+]i increases derived from internal stores were abolished by inhibitors of Ca-ATPase and the elevation of [Ca2+]i was occurred after the re-application of external Ca. 3) CA secretion was elicited by Ca released from internal stores in single voltage-clamped cells. 4) The molar ratio of CA to ATP was constant regardless of secretagogues used. 5) Tyrosine kinase inhibitors suppressed the store-dependent Ca entry in smooth muscle cells. 6) Non-selective cation channel blockers and La inhibited Ca entry but in a different manner each other. It was revealed that internal Ca stores play functional roles in many cellular responses, including the regulation of ionic channels, change in [Ca2+]i and exocytosis. Store-dependent Ca entry may be partly mediated by tyrosine kinases. Further research is needed to identify the functional molecules such as trp-gene products, responsible for the store-dependent Ca entry mechanisms.
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