Mechanisms of hibernation and cell protection during hypothermic condition in golden hamster

众所周知，金仓鼠在寒冷的环境中冬眠。仓鼠的冬眠分为进入期、维持期和唤醒期。在入口阶段，仓鼠的体温下降到接近环境温度，并在维持阶段继续下降。脑室内（i.c.v）给药腺苷（ADO）和ATP可使仓鼠体温过低。腺苷A1受体拮抗剂CPT抑制ADO和ATP产生的低温。此外，c.v.给药CHA，一种腺苷A1受体激动剂，将B.T.降低到几乎环境温度。静脉注射β-内啡肽导致体温过低呈剂量依赖性。选择性μ受体激动剂DAMGO也将bt降低到接近环境温度。在进入阶段，CPT的管理（i.c.v）产生了B.T的上升，但在维持阶段没有。维持期给予纳洛酮可使bt升高，而进入期则无升高。进入期下丘脑A1受体数量减少。上述结果表明，腺苷通过A1受体调控仓鼠入口期B.T.，阿片通过μ受体调控维持期B.T.。冬眠仓鼠在被唤醒时，体温从6℃迅速上升到37℃。褐色脂肪组织的生热作用是包括仓鼠在内的啮齿类动物热疗的重要组成部分。促甲状腺素释放激素（TRH）通过增加基础代谢产生高热。因此，我们研究了冬眠唤醒时中枢性TRH和BAT在热疗中的功能联系。在冬眠的仓鼠脑室内（i.c.v）施用TRH可产生高热，冬眠被中断。急性实验中，大鼠灌胃TRH后，直肠和肩胛骨间BAT （iBAT）温度升高。通过iBAT手术去神经和/或SR59230（一种β3肾上腺素受体拮抗剂）抑制TRH的高热效应。灌胃TRH引起iBAT去甲肾上腺素（NE）含量和NE周转率升高。这些结果表明，中枢TRH系统和外周BAT系统通过交感神经系统存在功能联系，并在冬眠唤醒时的热疗中发挥重要作用。少

It is known that golden hamster hibernates in cold environment. The hibernation of the hamster is classified into entrance stage, maintenance stage and arousal stage. In entrance stage, the body temperature (B.T.) of hamster lowers to almost environmental temperature, and the lowered B.T. continues in maintenance stage. Intracerebroventricular (i.c.v.) administrations of adenosine (ADO) and ATP produced hypothermia in hamster. The hypothermia produced by ADO and ATP suppressed by CPT, an adenosine A1 receptor antagonist. Moreover, i.c.v. administrated CHA, an adenosine A1 receptor agonist, lowered the B.T. to almost environmental temperature. I.c.v. administrated β-endorphin produced hypothermia in a dose-dependent manner. DAMGO, a selective μ-receptor agonist, also lowered the B.T. to almost environmental temperature. In entrance stage, administration (i.c.v.) of CPT produced uprise of the B.T., but did not in maintenance stage. Administration of naloxone in maintenance stage produced … More uprise of the B.T., but did not in entrance stage. The A1 receptor number of the hypothalamus in entrance stage decreased. These results suggest that adenosine regulates the B.T. of hamster in entrance stage via A1 receptor, and opioid regulates B.T. in maintenance stage via μ receptor.During arousal from hibernation, the body temperature of hibernating hamster rapidly rises from 6 ℃ to 37 ℃. Thermogenesis in brown adipose tissue (BAT) is import component for the hyperthermia in the rodents including hamster. Thyrotropin-releasing hormone (TRH) produces the hyperthermia by increase of base metabolism. Therefore, we investigated the functional linkage of central TRH and BAT in the hyperthermia during arousal from hibernation. Intracerebroventricular (i.c.v.) administration of TRH produced hyperthermia in the hibernating hamster, and the hibernation was interrupted. In acute experiment, temperature of rectum and inter scapular BAT (iBAT) rose by the i.c.v. administration of TRH. The hyperthermic effect of TRH was suppressed by surgical denervation of iBAT and/or administration of SR59230 , a β3 adrenoceptor antagonist. I.c.v. administration of TRH caused increase of norepinephrine (NE) content and NE turnover rate in the iBAT. These results suggest that central TRH system and peripheral BAT system have functionally linked through the sympathetic nervous system, and it is play an important role in the hyperthermia during arousal from hibernation. Less