| Project/Area Number |
06454020
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
生物形態・構造
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| Research Institution | Ocean Research Institute University of Tokyo |
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Principal Investigator |
TAKEI Yoshio Ocean Research Institute, University of Tokyo, Associate professor, 海洋研究所, 助教授 (10129249)
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| Co-Investigator(Kenkyū-buntansha) |
HYODO Susumu College of Arts and Sciences, University of Tokyo, Assistant professor, 教養学部, 助手 (40222244)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥7,200,000 (Direct Cost: ¥7,200,000)
Fiscal Year 1995: ¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 1994: ¥4,600,000 (Direct Cost: ¥4,600,000)
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| Keywords | Atrial notriuretic peptide / Ventricular natriuretic peptide / B-type natriuretic peptide / C-type natriuretic peptide / Eel, Anguilla japonica / Bullfrog, Rana catesbeiana / Osmoregulation / ANP receptors / 心房性ナトリウム利尿プペチド / 心室性ナトリウム利尿プペチド / B型ナトリウム利尿プペチド / C型ナトリウム利尿プペチド / ANP / BNP / CNP / 分泌調節 |
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| Research Abstract |
1. Plasma atrial and ventricular natriuretic peptide (ANP and VNP) levels increased transiently after transfer of eels from fresh water (FW) to seawater (SW). Injection of hypertonic solutions markedly increased plasma ANP and VNP levels, but blood volume expanasion was a much smaller secretagogue in the eel. ANP and VNP secretion increased in isolated, perfused eel heart after prefusate osmolality was increased These results show that osmotic requlation dominates volemic requlation for ANP and VNP secretion in the eel, and osmotic stimulus was perceived by cardiocytes themselves.
2. Whole-body autoradiography revealed dense accumulation of ^<125>I-eel ANP in the gill. Radio-ligand binding assay showed that most ANP receptors in the eel gill are clearance type NPR-C ; however, guanylate cyclase-coupled, CNP-specific NPR-B was also present in the gill of only FW eels. This is consistent with much less expression of NPR-B message in SW eels than in FW eels.
3. ANP inhibits drinking and intestinal absorption of water and sodium in both FW and eels. ANP also inhibits secretion of cortisol, a fish mineralocorticoid important for SW adaptation, and causes antidiuresis and natriuresis only in SW eels. It seems that ANP is a sodium extruding hormone in SW fish.
4. B-type natriuretic peptide (BNP) was isolated from the cardiac ventricle of bullfrog. Thus semiaquatic amphibians seem to have terapod-type BNP not fish-type VNP in their Ventriles.
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