Permalink : http://hdl.handle.net/2115/89101

JaLCDOI : 10.14943/lowtemsci.81.149

KEYWORDS : 冬眠;体温;アデノシン;オピオイド;甲状腺刺激ホルモン放出ホルモン（TRH）;hibernation;body temperature;adenosine;opioid;thyrotropin releasing hormone

シリアンハムスター（Mesocricetus auratus）は，寒冷・短日環境下で1ヶ月以上飼育すると環境温度付近（6℃）まで体温を低下させ冬眠を始める（導入期）．その後，数日間の非活動期（維持期）を経て，再び自力で正常体温まで覚醒する（覚醒期）．冬眠期間中はこの数日間の低体温期と中途覚醒を何度も繰り返す．我々はこれまでに，冬眠導入期・維持期・覚醒期の体温は，それぞれ，A1受容体を介したアデノシン系・mu1受容体を介したオピオイド系・R1受容体を介したTRH系の別々の中枢神経機構により制御されていることを明らかにしてきた．本稿ではそれぞれの体温制御機構を解説する．
Hibernation induced in Syrian hamsters by housing them in winter condition (L:D 8:16, Ta = 5℃) was confirmed by marked reductions in the body temperature (Tb) and respiratory rate. A hibernation bout of Syrian hamsters could be divided into entrance, maintenance and arousal phases according to changes in Tb. In the entrance phase, the adenosine system mediated by activating A1 receptors lowered Tb. During the maintenance phase, beta-endorphin which synthesizes in the arcuate nucleus related with sustenance of depressed Tb by activating mu-opioid receptors. In the arousal phase, the central thyrotropin-releasing hormone (TRH) system mediated by R1 receptor induced elevation of Tb. TRH-R1 activated non-shivering thermogenesis in brown adipose tissue via sympathetic nerve stimulation. In this paper, we review their thermoregulatory mechanisms in hibernating hamster.