| Project/Area Number |
18390068
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Environmental physiology (including Physical medicine and Nutritional physiology)
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| Research Institution | Asahikawa Medical College |
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Principal Investigator |
HASHIMOTO Masaaki Asahikawa Medical College, School of Medicine, Associate Professor (30156294)
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| Project Period (FY) |
2006 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥16,730,000 (Direct Cost: ¥14,600,000、Indirect Cost: ¥2,130,000)
Fiscal Year 2007: ¥9,230,000 (Direct Cost: ¥7,100,000、Indirect Cost: ¥2,130,000)
Fiscal Year 2006: ¥7,500,000 (Direct Cost: ¥7,500,000)
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| Keywords | hibernation / physiology / antioxidant / brain-nerve system / neurotransmitter / metabolic pathway / microdialysis / NMR / 脳 / 酸化ストレス / 尿酸 / アスコルビン酸 / グルタチオン / 微量透析 |
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| Research Abstract |
By using body-temperature-independent measuring system, endogenous water-soluble anti-oxidant in the Syrian hamster brain was measured along the time course of hibernation. Moreover, the metabolic products were traced by administering a metabolic substrate (glucose and lactic acid) through the microdialisys probe to the hamster brain under hibernation (body temperature about 6℃) with the radioactive and the non-radioactive isotope, by means of using HPLC and the nuclear magnetic resonance (NMR) method. In addition, the isotope-labeled glucose was injected through the chronic femoral vein catheter, and a similar measurement was done. 1) Blood glucose level was relatively well maintained constant throughout the hibernation, while the labeled glucose decreased as time goes by. 2) Brain tissue level of the antioxidant (ascorbic acid, glutathione) was invariable but uric acid decreased to 1/2-1/3. 3) In the brain ECF: ascorbic acid level was higher in the hibernating animals than in the awaking animals, and decreased along the time course of arousing from hibernation. The uric acid level did not change except for a transient elevation during arousal phase of hibernation. Glutathione level showed temperature dependent changes in positive correlation. 4) Blockade of the purine nucleotide metabolism to the uric acid inhibited both the transient increase of uric acid and decrease of ascorbic acid.
These results suggested that blood glucose level is well maintained during hibernation, and the ascorbic acid functioned against the oxidation stress guessed during arousal from hibernation.
5) Though the glutamine, the glutamic acid, and GABA in the brain tissue homogenate increased during deep hibernation, these were not detected in the brain ECF.
The glutamine-glutamate cycle between the neurons and the astrocytes seems not to be functional while hibernating. These findings may be useful to forecast the beginning of hibernation as a marker.
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