Department of Nutritional Science, National Institute of Health and Nutrition, 1-23-1 Toyama, Shinjuku 162-8636, Japan.
Neuroscience. 2012 Dec 13;226:73-80. doi: 10.1016/j.neuroscience.2012.09.033. Epub 2012 Sep 19.
Hypoxia evokes a regulated decrease in the body core temperature, which response is mediated, at least in part, by noradrenaline (NA) and nitric oxide (NO) in the rostromedial preoptic area (POA) of the hypothalamus. In the accompanying paper, it was shown that glutamatergic activation of the lateral POA also evokes hypothermic responses. Here, I tested the hypothesis that the glutamatergic transmission in the lateral POA is critically involved in the neural mechanism of hypoxia-induced hypothermia. Hypoxic ventilation (10% O(2)-90% N(2), 5 min) as well as a single microinjection of NA (50 pmol) or the NO donor sodium nitroprusside (8.4 nmol) into the rostromedial POA evoked an increase in the tail skin temperature and a decrease in the colonic temperature in urethane-chloralose-anesthetized, neuromuscularly blocked, artificially ventilated rats. All of these responses were greatly attenuated by pretreatment with multiple microinjections of kynurenic acid (10 nmol, four locations), a nonselective glutamate receptor antagonist, but not by those with saline solution, in the bilateral rostral and central parts of the lateral POA. These results suggest that the NA- and NO-sensitive structure in the rostromedial POA activated the glutamatergic transmission in the lateral POA to mediate hypoxia-induced hypothermia.
缺氧会引起体温核心下降，这种反应至少部分是由下丘脑前视区（POA）中的去甲肾上腺素（NA）和一氧化氮（NO）介导的。在随附的论文中，已经表明外侧 POA 的谷氨酸能激活也会引起体温降低反应。在这里，我测试了这样一个假设，即外侧 POA 中的谷氨酸能传递对于缺氧诱导的体温降低的神经机制至关重要。缺氧通气（10% O2-90% N2，5 分钟）以及 NA（50 pmol）或 NO 供体硝普钠（8.4 nmol）单次微注射到前视区会引起大鼠尾皮温度升高和结肠温度降低。这些反应在双侧前侧和中央侧 POA 的多微注射犬尿氨酸（10 nmol，四个部位）预处理后，即非选择性谷氨酸受体拮抗剂后，均大大减弱，但在生理盐水处理后并未减弱。这些结果表明，前视区中对 NA 和 NO 敏感的结构激活了外侧 POA 中的谷氨酸能传递，以介导缺氧诱导的体温降低。
