| Project/Area Number |
11640681
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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 | KYUSHU UNIVERSITY |
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Principal Investigator |
ICHIKAWA Toshio Graduate Schools Faculty of Sciences, KYUSHU UNIVERSITY, Associate Proffesor, 大学院・理学研究院, 助教授 (50136420)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2000: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1999: ¥2,800,000 (Direct Cost: ¥2,800,000)
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| Keywords | Bombyx mori / Neurosecretory cells / coupling / synchronization / ultradian rhythm / correlation / multi-oscillator system / fluctuation / カップリング / スパイク同期 / 相関 / 多振動体 / 同期的発火 / ギャップ結合 / モジュール / 麻酔 |
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| Research Abstract |
There are four pairs of neurosecretory cells producing bombyxin, an insulin-related peptide, in the brain of Bombyx mori. Electrical signals of the bombyxin-producing cells were identified and short-and long-term activity patterns of the cells throughout the pupal period were analyzed. Activity pattern of the cells was characterized by periodic discharges of a volley of action potentials. Periodicity of the electrical activity depended on the temperature and mean±SD of periods was 34.7±4.8 min at 26℃. Four cells in a brain hemisphere were functionally heterogeneous : individual cells had specific activity amplitudes and rhythms, thereby suggesting that an ultradian activity rhythm of a cell originates from its intrinsic pacemaker activity. There was no significant diel (circadian) oscillation in the electrical activity. Daily activity patterns had a maximum at an early stage (day-2 or 3) of pupal period. Firing correlations were examined among four pairs of bombyxin-producing cells with an ultradian bursting rhythm. Cross-correlation analyses of spiking activities between pairs of simultaneously active cells usually revealed a significant correlation of firings : 20-50% of spikes of a cell fired within 0.2 s before or after the other cell's spikes fired. The mutual, excitatory communication among neurosecretory cells make the set of cells a weakly coupled multi-oscillator system that may generates a pulsatile release pattern of their hormone that seems to be an efficient temporal pattern for maintaining hormonal actions.
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