| Project/Area Number |
12640655
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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 |
生物形態・構造
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| Research Institution | St. Marianna University School of Medicine |
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Principal Investigator |
ITOH Masanori St. Marianna University School of Medicine, Department od Chemistry, Assistant Professor, 医学部, 講師 (30257349)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2001: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2000: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | circadian clock / development / nervous system / melatonin / serotonin / noradrenaline / cricket / planarian / 初期胚 / 孵化 / 脳 |
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| Research Abstract |
1. Temporal profiles of hatching in cricket (Gryllus bimaculatus) eggs incubated under different lighting regimens were examined. The results demonstrate that, by midembryogenesis, the embryonic circadian clock has been formed and is entrainable to 24-h light/dark cycles. In addition, the photoperiodic conditions to which the parents (probably the mothers) have been exposed influence the timing of egg hatching, suggesting that maternal factors regulate the timing of egg hatching.
2. In the freshwater planarian Dugesia japonica, which belongs to most primitive metazoan phylum, serotonin was detected. Serotonin was localized in the cephalic ganglion (brain), in the main nerve cords extending posteriorly from the brain and in the commissure axons connecting the main nerve cords. The serotonin levels fluctuated with circadian rhythm, demonstrating the existence of a circadian timekeeping mechanism in planarian.
3. To examine the effect of melatonin on in vitro fertilization and embryonic development, mouse embryos alter insemination in vitro were cultured in a physiological medium with or without melatonin. Melatonin increased the fertilization rate and the rate of early embryo development.
4. The concentrations of noradrenaline in preovulatory follicular fluid obtained from women undergoing in vitro fertilization were determined and compared with those in peripheral plasma obtained currently. All of the follicular fluid samples contained noradrenaline at concentrations substantially higher than those in the corresponding plasma samples. A positive correlation was found between noradrenaline levels in follicular fluid and plasma in each woman. The data suggest that the main source of noradrenaline in the follicular fluid could be the general circulation.
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