| Co-Investigator(Kenkyū-buntansha) |
OHINATA Hiroshi Asahikawa Medical College, Medicine, Assistant Professor, 医学部, 助手 (20233257)
UTSUMI Kazue Asahikawa Medical College, Medicine, Assistant Professor, 医学部, 助手 (90271759)
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| Research Abstract |
A series of studies was carried out to investigate the physiological changes that could be an indicator for entrance and exit of the hibernation.
The level of mRNA of uncoupling protein 1(UCP1 mRNA) in the brown adipose tissue (BAT), a key protein to be served as a energy balance regulator through heat production, was not changed during hibernation period in hamsters, though was in higher level compared with summer animals. We confirmed that gene expression was not newly performed during deep hibernation in the major organs, such as the heart, brain, liver, including BAT. Therefore the increased UCP1 mRNA level in deep hibernating animals is considered to be due to the enhanced production during inter-bout arousal cenothermia.
BAT thermogenesis is well synchronized with control of blood supply to BAT. We clarified that endothelium type nitric oxide synthetase plays an important role in the mechanism of blood supply to BAT.
BAT heat production is augmented not only by chill stress but by immobilization stress. If the immobilization stress is added repetitively in rats, adaptation will take place and thermogenic function is enhanced. In the thermogenesis enhancement, modulation of UCP1 gene expression was involved.
Continuous in vivo measurement revealed that at the time of awakening from hibernation, the brain would be possibly exposed to transient oxidization stress of high level due to sudden increase in blood flow, and that is suggesting that existence of an anti-oxidization defense function.
To use in telemetry of the substances relating to energy metabolism, we developed fine-wire electrode coated with enzyme containing polymer However, the sensitivity of electrode to substances in the brain was decreased concomitantly with temperature decreases during hibernation. Therefore, we used the electrode for ex vivo measurements of the samples collected from the brain by using microdialysis method, and got good results.
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