2005 Fiscal Year Final Research Report Summary
Generation mechanism and functional significance of rhythmic activity of flight muscles in the insect postembryonic development
| Project/Area Number |
16570065
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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 |
Animal physiology/Animal behavior
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
ICHIKAWA Toshio Kyushu University, Faculty of Sciences, Associate professor, 理学研究院, 助教授 (50136420)
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| Project Period (FY) |
2004 – 2005
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| Keywords | Silkmoth / neurosecretory cells / neuropeptides / flight muscles / muscle development / ultradian rhythm / colocalization / immunocytochemistry |
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| Research Abstract |
Ultradian rhythmic firing activity of a population of neurosecretory cells (NSCs) producing FXPRLamide peptides in the subesophageal ganglion (SG) of the silkmoth Bombyx mori is closely coordinated with periodically occurring electrical activity of developing flight muscles (FMs) during metamorphosis. Similar rhythmic discharges of flight pattern-like motor activity were recorded from the developing asynchronous flight muscles of the fly (Drosophila melanogaster and Protophormia terraenovae), honeybee (Apis mellifera), wasp (Vespa analis), and beetle (Tenebrio obscurus) but not from the nymph of locust (Locusta migratoria). To examine the functional role of the electrical activity of FMs on the muscle development, the flight muscles of B.mori were unilaterally denervated at a middle pupal stage. The weight of denervated muscles was 10% smaller than that of contralateral innervated muscles, and the contraction kinetics of the denervated muscles was significantly slower than that of the innervated ones. The removal of the SG at a middle pupal stage had no effect on the metabolic enzyme activity of adult FMs. Immunocytochemical studies revealed that FXPRLamide-immunoreactive NSCs in B.mori colocalize FMRFamide and Bombyx myosuppressin (BMS) and those NSCs in the mealworm beetle T.obscurus colocalize FMRFamide and pigment dispersing factor (PDF). The NSCs in T.obscurus became active during the middle and late pupal periods, and they usually discharged clusters of action potentials at an interval of 30-90 min. The ultradian activity rhythm of the NSCs in the mealworm closely synchronized with periodically occurring rhythmic abdominal movements that caused extracardiac hemocoelic pulsations to facilitate hemolymph circulation and exchange of respiratory gases. The result suggests that the secretory products of the NSCs in the SG may activate and/or orchestrate various physiological mechanisms supporting morphogenesis during metamorphosis.
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Research Products
(9 results)
