| Budget Amount *help |
¥14,900,000 (Direct Cost: ¥14,900,000)
Fiscal Year 2005: ¥7,000,000 (Direct Cost: ¥7,000,000)
Fiscal Year 2004: ¥7,900,000 (Direct Cost: ¥7,900,000)
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| Research Abstract |
During arousal from hibernation, small mammal whose body temperature is by about 1℃ higher than the freezing environment shows the temperature rise of more than 30℃ in several hours. Because of the intense increases in the energy metabolism at that time, the major organs such as the brain and heart are thought to be exposed to a strong oxidation stress. Hibernators are, however, assumed to be equipped with anti-oxidation mechanism since they do not show any pathology throughout the hibernation period. In this study, we investigated the underlying mechanism of arousal from hibernation and of anti oxidation stress in Syrian hamsters, and the following results have been acquired so far.
1.During deep hibernation, there is no de-novo synthesis of protein and mRNA, namely any transcription and translation of the gene stop in the body. The gene expression is restarted accompanying to an increase in the energy metabolism in the arousal phase of hibernation. (Jpn.J.Physiol,2004,54)
2.Once arousal from hibernation begins, the blood distributed to caudal half of the body temporarily moves to rostral side owing to an increase in the sympathetic nerves activities of the vasculature in the caudal body, which results in the increase of blood distribution to the brain. (Am.J.Physiol.2005)
3.Uric acid, an index of oxidation stress, in the extra cellular fluid (ECF) of the brain increased temporarily in the arousal phase. The brain ECF level of ascorbic acid, a water soluble antioxidants, increases during deep hibernation, which reduces as the arousal phase advances. ECF glutathione (GSH) changes like a mirror image of the change of ascorbic acid during hibernation. Brain tissue ascorbic acid and GSH does not change, but uric acid increases as arousal from hibernation advances. (Behav.Brain Res,2006)
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