1997 Fiscal Year Final Research Report Summary
Complexity of the regulatory system for motile activities of teleostean chromatophores and its physiological significance
| Project/Area Number |
08640875
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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 |
動物生理・代謝
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| Research Institution | Toho University, Faculty Scinece |
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Principal Investigator |
FUJII Ryozo Toho University, Faculty of Science, Department of Biomolecular Science, Professor, 理学部, 教授 (10045354)
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| Co-Investigator(Kenkyū-buntansha) |
SUGIMOTO Masazumi Toho University, Faculty of Science, Departent of Biomolecular Science, Lecturer, 理学部, 講師 (20235899)
OSHIMA Noriko Toho University, Faculty of Science, Departent of Biomolecular Science Professor, 理学部, 教授 (70057735)
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| Project Period (FY) |
1996 – 1997
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| Keywords | Chromatophore / Melanophore / Leucophore / Endothelin / Hormone / Skin coloration / Poikilothermal vertebrate / Fish |
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| Research Abstract |
Endothelins effectively aggregated melanosomes within melanophores of several species of teleosts. Using highly specific agonists and antagonists, we concluded that the receptors for endothelins resemble those of the mammalian ET_B type. Similar results were obtained on the endothelin receptors of xanthophores and erythrophores.By making use of high quality operational amplifiers, an inproved photoelectric method for recording motile responses of individual leucophores was developed. This method could also be applied to the study of the motile responses of dendritic iridophores of the Odontobutis type. Employing this method, we studied the effects of endothelins on the leucophores of the medaka, Oryzias latipes, and found that the peptides strongly disperse light-scattering organelles, the leucosomes. Since the direction of the organeliar movements in leucophores was reverse to that observed in the light-absorbing chromatophores, we should examine the second messenger system in the former cells. Limited numbers of melanophores and xanthophores exist in the skin and also inside the body of the ice goby, Leucopsarion petersii. The fact that the chromatophores existing deep inside the body take active part in the color changes was first reported. Measurements of spectral reflectance from the sky blue portion of the common surgeonfish, Pracanthurus hepatus, showed that a relatively steep peak stood around 490 nm. We concluded that the multilayred thin-film interference phenomenon of the non-ideal type occurring in the stacks of very thin light-reflecting platelets in iridophores is primarily responsible.
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