| Project/Area Number |
08640857
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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 | University of Tsukuba |
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Principal Investigator |
YAMAGISHI Hiroshi Institute of Biological Sciences, University of Tsukuba, Assistant Professor, 生物科学系, 講師 (80092534)
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| Co-Investigator(Kenkyū-buntansha) |
YAZAWA Tohru Faculty of Science, Tokyo Metropolitan University, Research Associate, 理学部, 助手 (30106603)
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| Project Period (FY) |
1996 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1997: ¥500,000 (Direct Cost: ¥500,000)
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| Keywords | Crustacea / Ligia exotica / heart / pacemaker / ontogeny / heart regulation |
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| Research Abstract |
The aim of the present study is to elucidate the ontogenetic and phylogenetic diversity of the heartbeat and its regulatory mechanisms in crustaceans. The experiments were performed using histochemical and electrophysiological methods. The results obtained were as follows : 1) We achieved the way to keep the colony of the isopod crustacean Ligia exotica in the laboratory and described its developmental stages. Based on these results, we showed that the heart pacemaker of Ligia exotica is transferred from the heart muscle to the cardiac ganglion during juvenile development and the heartbeat changes from myogenic to neurogenic. Moreover, we showed that the mechanism of the neurogenic heartbeat of the adults is different from that known previously in another crustaceans. 2) We identified one pair of cardioinhibitory and two pairs of cardioacceleratory neurons in the central nervous system of Ligia exotica, and showed that these cardioregulaory neurous innervate both the cardiac ganglion neurons and the myocardium. Moreover, we showed developmental changes in nervous regulation of the heartbeat associatd with the pacemaker transfer during juvenile development. 3) We showed developmental changes in hormonal regulation, especially in aminergic modulation of the heartbeat associated with the pacemaker transfer during juvenile development of Ligia exotica. 4) We found the myogeniic heartbeat in the primitive crustacean Triops longicaudatus and demonstrate first the presence of the myogenic heart in crustacea. We submitted five papers on the above results to professional journals and these papers have been published. We are preparing another some papers on the results.
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