| Project/Area Number |
02640557
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
動物発生・生理学
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| Research Institution | Okayama University |
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Principal Investigator |
SAKAI Masaki Okayama Univ. Assoc. Prof., 理学部, 助教授 (30027502)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAGUCHI Tsuneo Okayama Univ. Prof., 理学部, 教授 (60000816)
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| Project Period (FY) |
1990 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1991: ¥200,000 (Direct Cost: ¥200,000)
Fiscal Year 1990: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | Insect / Cricket / Mating behavior / Serotonin / Mating cycle / Reproductive behavior / Behavioral switching / Sexual refractoriness / 行動の切り替え / 生体アミン / オクトパミン |
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| Research Abstract |
(1)Mating in the male cricket Gryllus bimaculatus proceeds as a result of a stimulus-response chain. The final act, spermatophore extrusion, is elicited by mechanical stimulation of small sensilla in the cavity enclosed by the epiphallus. In normal copulation, stimulation for this seems to be made by insertion of the female's copulatory papilla into the cavity. To induce spermatophore extrusion efficiently, the bodily tonus had to be heightend, eliciting male copulatory actions by giving key stimuli to the body surface in a sexually excited state
(2)Spontaneous spike activity of ascending neurons was recorded from the ventral nerve cord before and after artificially induced spermatohore extrusion. After spermatophore extrusion, most spikes stopped discharging. In 10 min the spike activity began to recover but it was much less than before spermatophore extrusion. It suggests that some neurons in the terminal abdominal ganglion signals the end of mating to the brain by silence.
(3)Effects of biogenic amines were examined on the duration of sexually inactive period defined as a period between spermatophore protrusion and calling song initiation. Drugs were injected into the body cavity after spermatophore protrusion, and some males were left intact to wait for calling song initiation and others were decapitated to see when copulation response was ecited. Serotonin delayed initiation of a calling song by about 5 min. On the other hand, 5-hydroxitriphtophan, UV-irradiated serotonin and 5-7 dihydroxitriptamine-treatment significantly advanced both calling song initiation in intact and copulation response in decapitated males. These suggest that serotonin may underlie male's sexual refractoriness.
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