2000 Fiscal Year Final Research Report Summary
Nervous System of Echinoderms with special reference to the neuropeptide NGIWY amide that controls catch connective tissues.
| Project/Area Number |
11640676
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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 | Tokyo Institute of Technology |
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Principal Investigator |
MOTOKAWA Tatsuo Tokyo Institute of Technology, Graduate School of Bioscience and Biotechnology, Professor, 大学院・生命理工学研究科, 教授 (80092352)
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| Project Period (FY) |
1999 – 2000
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| Keywords | echinoderms / nervous system / catch connective tissue / neuropeptide |
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| Research Abstract |
1. I extracted from a sea cucumber a peptide that stiffens the holothurian catch connective tissue. The amino acid sequence of the peptide was Asn-Gly-Ily-Trp-Tyr-NH_2 (NGIWYamide). The antibody against NGIWY amide was raised. Immunoreactivity to this antibody was observed in the following parts of sea cucumbers : both ectoneural and hyponeural parts of radial nerve, circumoral nerve ring, tentacle nerve, cell processes in body-wall dermis. NGIWY amide caused contraction of longitudinal body wall muscles whereas it inhibited the spontaneous contraction of gut.
2. Immunoreactivity was observed in sea urchins also. Positively stained parts were as follows : radial nerve, nerve ring surrounding spine base, nerve processes between muscle sheets and those between spine muscle and catch apparatus, and podial nerve. NGIWY amide inhibited the contraction of tube feet induced by acetylcholine.
3. Immunoreactivity was observed in starfish also. Positively stained parts were as follows : both ectoneural part and hyponeural part of radial nerve, marginal nerve, and podial nerve. NGIWY amide caused contraction of tube feet. These results established that NGIWY amide is a ubiquitous echinoderm neuropeptide that controls muscles and catch connective tissues.
4. The nervous system of crinoids are considerably different from those of other echinoderm classes. The light and electron microscopic observations revealed that the cell with bullet shaped organelles (BSO cell) makes a network of cellular processes that originates from the perifery of the coelomic nerve, ramifies and covers the entire stereom space of an ossicle. The processes have close contact with cell bodies of juxtaligamental cell which is supposed to control the mechanical properties of ligaments. The network of BSO cells seems to work as a nervous system that controls the connective tissue activities such as connective tissue catch and contraction.
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