2005 Fiscal Year Final Research Report Summary
Physiological characteristics of pikas as the animal adapted to extreme environments of "cold and high-altitude"
| Project/Area Number |
15406007
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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 | 海外学術 |
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| Research Field |
Environmental physiology (including Physical medicine and Nutritional physiology)
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| Research Institution | Chukyo University (2005)
Aichi Medical University (2003-2004) |
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Principal Investigator |
MATSUMOTO Takaaki Chukyo University, School of Health and Sport Sciences, Professor, 体育学部, 教授 (60199875)
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| Co-Investigator(Kenkyū-buntansha) |
SAKAI Akio Shinshu University, School of Medicine, Associate Professor, 大学院医学研究科, 助教授 (70020758)
SAITO Muneo Central Institute for Experimental Animals, Head ofLaboratory Animals Center, 実験動物研究部, 室長 (50167417)
MATSUZAKI Tetsuya Central Institute for Experimental Animals, Head of Laboratory Animals Center, 実験動物研究部, 室長 (30167647)
YAHATA Takehiro Nayoro City College, School of Nursing, Professor, 看護学科, 教授 (60041828)
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| Project Period (FY) |
2003 – 2005
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| Keywords | pika / cold adaptation / high-altitude adaptation / circadian rhythm / brown adipose tissue / UCP1 / China / Mongolia |
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| Research Abstract |
1) Recording the body temperature rhythm of wild pikas by field telemetry method showed clearly that a pika is essentially diurnal both in summer and in winter. 2) Whole year monitoring of burrow and outside temperatures showed that the burrow (an underground tunnel network or the space between the rocks) play an important role as a shelter not only against for natural enemies but also for summer heat and winter cold. 3) Monitoring the body temperature of the wild pika in winter suggested the un-hibernating nature of pikas strongly. 4) Generally, cardiac weight (right/left heart weight ratio) increased by cold in addition to low oxygen in winter, but it did not increase in winter compared with the value of a summer in the wild pika, as same as in the other animals living under ground. 5) The oxygen consumption of the pika became the minimum value at 20 ℃, and was lower than that of the rat at the temperatures between 0 and 30 ℃. 6) As a result of comparing the heat production ability of the brown adipose tissue (BAT) of wild pikas with rats, it was clarified that BAT play an important role in cold-tolerance in pikas. 7) In the pikas reared in the warm, BAT was whitish like white adipose tissue and was composed of a large lipid droplet in electro-microscopic observation. In the pikas exposed to acute cold, most cytoplasm was seen in the small cells. BAT uncoupling protein (UCP1) mRNA was identified in all pikas, and the intensity of UCP1mRNA become strong by acute cold exposure. As a result of the partial analysis of the base sequence of UCP1mRNA, pika UCP1 showed the highest homology with rabbit UCP1.
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