Shimaoka Hiroki, Kawaguchi Takayuki, Morikawa Kahori, Sano Yuuki, Naitou Kiyotada, Nakamori Hiroyuki, Shiina Takahiko, Shimizu Yasutake
Department of Basic Veterinary Science, Laboratory of Physiology, The United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan.
Laboratory of Veterinary Physiology, Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan.
J Physiol Sci. 2018 Jul;68(4):425-430. doi: 10.1007/s12576-017-0543-y. Epub 2017 May 15.
Central adenosine A1-receptor (A1AR)-mediated signals play a role in the induction of hibernation. We determined whether activation of the central A1AR enables rats to maintain normal sinus rhythm even after their body temperature has decreased to less than 20 °C. Intracerebroventricular injection of an adenosine A1 agonist, N6-cyclohexyladenosine (CHA), followed by cooling decreased the body temperature of rats to less than 20 °C. Normal sinus rhythm was fundamentally maintained during the extreme hypothermia. In contrast, forced induction of hypothermia by cooling anesthetized rats caused cardiac arrest. Additional administration of pentobarbital to rats in which hypothermia was induced by CHA also caused cardiac arrest, suggesting that the operation of some beneficial mechanisms that are not activated under anesthesia may be essential to keep heart beat under the hypothermia. These results suggest that central A1AR-mediated signals in the absence of anesthetics would provide an appropriate condition for maintaining normal sinus rhythm during extreme hypothermia.
中枢腺苷 A1 受体（A1AR）介导的信号在诱导冬眠中起作用。我们确定中枢 A1AR 的激活是否能使大鼠即使在体温降至 20℃以下后仍维持正常窦性心律。脑室内注射腺苷 A1 激动剂 N6-环己基腺苷（CHA），随后进行降温，可使大鼠体温降至 20℃以下。在极度低温期间，基本维持了正常窦性心律。相比之下，通过冷却麻醉大鼠强制诱导低温会导致心脏骤停。对由 CHA 诱导低温的大鼠额外给予戊巴比妥也会导致心脏骤停，这表明在麻醉状态下未激活的一些有益机制的运作可能对在低温下维持心跳至关重要。这些结果表明，在没有麻醉剂的情况下，中枢 A1AR 介导的信号将为在极度低温期间维持正常窦性心律提供合适的条件。
