2002 Fiscal Year Final Research Report Summary
Neural mechanisms of mating behavior in insects with special reference to the execution and termination of copulation
| Project/Area Number |
13640680
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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 | OKAYAMA UNIVERSITY |
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Principal Investigator |
SAKAI Masaki Prof of Okayama Univ. The Grad Sch Nat Sci Tech, 大学院・自然科学研究科, 教授 (30027502)
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| Project Period (FY) |
2001 – 2002
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| Keywords | cricket / reproduction / refractoriness / mating / nervous system / timer / 5-HT / 5-HTP |
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| Research Abstract |
This study addresses a potentially general basis of measuring time in a biological timer. Here, we examined the effects of biogenic amines on the time-fixed post-copulatory sexually refractory stage (ca. 1h) which is defined as the time interval between spermatophore protrusion and the onset of a calling or a mating response in the reproductive cycle of the male cricket. For subcuticular injection of amines (0.15 ml, 10^<-2>M), the interval of the .refractory stage was shortened by octopamine, serotonin, 5-hydoxytryptophan (5-HTP), N-acetyl-serotonin while unchanged by tryptophan, melatonin or 5-hydroxyindol-3-acetic acid. The effect of 5-HTP was most potent (maximum shortening, 38%) and longlasting (ca. 4-5 h) while other amines effected only the injected cycle. Injection of 5-HTP (180 nl, 10^<-2>M) into the terminal abdominal ganglion also decreased the interval to a similar extent. Simultaneous injection of 5-HTP with the inhibitor of the 5-HT synthesis enzyme reduced the 5-HTP effect suggesting that this effect results from synthesis of serotonin from 5-HTP. The protein synthesis inhibitor cycloheximide had no effect on the interval. These results suggest that the reproductive timer is regulated by serotoneigic neurons in the terminal abdominal ganglion without protein synthesis during the interval of the time-fixed sexually refractory stage.
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