Budget Amount *help |
¥5,200,000 (Direct Cost: ¥4,000,000、Indirect Cost: ¥1,200,000)
Fiscal Year 2014: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2013: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2012: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000)
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Outline of Final Research Achievements |
The diurnal variation of performance in hippocampus-dependent learning tasks in rats and the effect of the pineal hormone melatonin on such performance were examined. Rats were subjected to the novel object recognition (NOR) task or the novel location recognition (NLR) task at either of four time zones of the day; the results showed that the performance was higher at night than during the daytime. When melatonin was injected into rats before the training phase of the NLR task, they showed improvement of performance in the daytime, but impairment at night, suggesting that melatonin within a certain concentration range may act to promote memory performance. Using rat hippocampal slice preparations, the effects of melatonin on the long-term depression (LTD) of CA1 synaptic responses were examined; the results showed that NMDA receptor-dependent LTD was promoted by melatonin, but metabotropic glutamate receptor-dependent LTD was not regulated by it.
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