1986 Fiscal Year Final Research Report Summary
Photoperiodic regulation of pineal and plasma melatonin levels in intact or pinealectomized chickens.
| Project/Area Number |
60480078
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
畜産学(含草地学)
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| Research Institution | Gifu University |
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Principal Investigator |
TANABE Yuichi Professor, Faculty of Agriculture, Gifu University, 農学部, 教授 (30021679)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAMURA Takao Associate Professor, Faculty of Agriculture, Gifu University, 農学部, 助教授 (60021698)
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| Project Period (FY) |
1985 – 1986
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| Keywords | circadian rhythm / plasma melatonin levels / adaptation to new photoperiodism / ラジオイムノアッセイ / サーカディアンリズム / 松果体細胞の明暗リズムの記憶 / 加齢 |
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| Research Abstract |
Photoperiodic regulation of plasma melatonin levels in intact or pinealectomized chicken was studied to elucidate the role of pineal gland in circadian rhythm of the chicken. Under a 14L:10D photoperiod, a circadian rhythm in plasma melatonin disappearred in pinealectomized chickens (pinealectomized at 1 day of age) at 16, 29, 65 and 100 days of age, whereas the rhythm was always observed either in intact or sham-operated chickens at corresponding ages. When 14-day-old cockerels and pullets, which had been kept under a 12D:12L photoperiod, were shifted to a 12L:12D photoperiod, a circadian plasma melatonin rhythm disappered in the first dark period, but resumed in the second dark period. When the cockerels which had been kept under a 12L:12D photoperiod, were shifted to a 12D:12L photoperiod, the first nocturnal rise of plasma melatonin appered in the second dark period in a reduced magnitude, and in the third dark period in a greater magnitude. When 82-day-old pullets, which had been kept under a 12D:12L photoperiod. were shifted to a 12L:12D photopriod, plasma melatonin rise was observed in the first dark time. Similar results were observed in the photoperiodic shift in 450-day-old pullets. These results indicate the decrease in the strength of memory for circadian light-dark rhythms with advancing age in the chicken.
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