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Cold-induced thermogenesis requires GABA in the preoptic area of the hypothalamus

寒冷诱导的产热需要下丘脑视前区的 GABA

基本信息

批准号：
15590218
负责人：
OSAKA Toshimasa
金额：
$ 2.18万
依托单位：
National Institute of Health and Nutrition
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15590218/
关键词：
cold-induced thermogenesis rat autonomic nervous system oxygen consumption GABA preoptic area adrenal medulla beta adrenoceptor 脳下位脳幹

项目摘要

Bilateral microinjections of GABA (300 mM, 100 nl) or the GABA_A receptor agonist muscimol (100 μM, 100 nl) into the preoptic area (POA) of the hypothalamus increased both the rate of whole-body oxygen consumption (VO2) and the body core (colonic) temperature of urethane-chloralose-anesthetized, artificially ventilated rats. The GABA-induced thermogenesis was accompanied by a tachycardic response and electromyographic (EMG) activity recorded from the femoral or neck muscles. Pretreatment with muscle relaxants (1 mg/kg pancuronium bromide plus 4 mg/kg vecuronium bromide, I.V.) prevented the GABA-induced EMG activity but had no significant effect on the GABA-induced thermogenesis. However, pretreatment with the β-adrenoceptor propranolol (5 mg/kg, I.V.) greatly attenuated the GABA-induced increase in VO2 and tachycardic responses. Accordingly, the GABA-induced increase in VO2 reflected mainly nonshivering thermogenesis. On the other hand, cooling of the shaved back of the rat by contact with a plastic bag containing 28 ℃ water also elicited thermogenic, tachycardic, and EMG responses. Bilateral microinjections of the GABA_A receptor antagonist bicuculline (500 μM, 100 nl), but not those of vehicle saline, into the POA blocked these skin cooling-induced responses. These results suggest that cold-induced thermogenesis requires GABA and GABA_A receptors in the POA.

将GABA（300 mM，100 nl）或GABA_A受体激动剂蝇蕈醇（100 μM，100 nl）双侧微量注射到下丘脑视前区（POA），可增加氯醛糖麻醉、人工通气大鼠的全身耗氧率（VO 2）和体核（结肠）温度。GABA诱导的产热伴随着从股骨或颈部肌肉记录的心动过速反应和肌电图（EMG）活动。肌肉松弛剂预处理（1 mg/kg泮库溴铵+4 mg/kg维库溴铵，静脉注射）抑制GABA诱导的肌电活动，但对GABA诱导的产热无明显影响。然而，用β-肾上腺素受体普萘洛尔（5 mg/kg，I. V.）大大减弱GABA诱导的VO 2和心动过速反应的增加。因此，GABA诱导的VO 2增加主要反映了非颤抖性产热。另一方面，通过接触装有28 ℃水的塑料袋冷却大鼠剃毛的背部也引起产热、心动过速和EMG反应。双侧POA微量注射GABA_A受体拮抗剂荷包牡丹碱（bicuculline，500 μM，100 nl）可阻断皮肤冷却诱导的上述反应。这些结果表明，冷诱导的产热作用需要GABA和GABA_A受体参与。