The physiological role of orexin/hypocretin neurons in the regulation of sleep/wakefulness and neuroendocrine functions.
The physiological role of orexin/hypocretin neurons in the regulation of sleep/wakefulness and neuroendocrine functions.
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DOI：
10.3389/fendo.2013.00018
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发表时间：
2013
影响因子：
5.2
通讯作者：
Yamanaka A
中科院分区：
文献类型：
--
作者：
Inutsuka A;Yamanaka A
下丘脑监测机体内稳态并调节各种行为，如摄食、产热和睡眠。食欲素（也称为下丘脑素）被鉴定为下丘脑外侧区两个孤儿g蛋白偶联受体的内源性配体。它们最初被认为是摄食行为的调节器，但它们主要被认为是睡眠/觉醒周期的关键调节器。食欲素激活下丘脑/脑干区域的食欲素神经元、单胺能神经元和胆碱能神经元，以维持长时间、巩固的清醒期。对转基因小鼠食欲素神经元神经投射和表型特征的解剖研究揭示了食欲素神经元在情绪协调、能量稳态、奖励系统和觉醒等方面的多种作用。例如，食欲素神经元受外周代谢信号的调节，包括生长素、瘦素和葡萄糖浓度。这表明它们可能在能量稳态和觉醒状态之间提供了一种联系。边缘系统和食欲素神经元之间的联系可能对提高情绪刺激时的警觉性很重要。食欲素也与奖赏系统和药物成瘾机制有关。这些发现表明，食欲素神经元感知身体的外部和内部环境，并维持动物生存所需的适当清醒水平。本文讨论了食欲素维持睡眠/清醒状态的机制，以及该机制与调节情绪、奖励和能量稳态的其他系统的关系。
The hypothalamus monitors body homeostasis and regulates various behaviors such as feeding, thermogenesis, and sleeping. Orexins (also known as hypocretins) were identified as endogenous ligands for two orphan G-protein-coupled receptors in the lateral hypothalamic area. They were initially recognized as regulators of feeding behavior, but they are mainly regarded as key modulators of the sleep/wakefulness cycle. Orexins activate orexin neurons, monoaminergic and cholinergic neurons in the hypothalamus/brainstem regions, to maintain a long, consolidated awake period. Anatomical studies of neural projections from/to orexin neurons and phenotypic characterization of transgenic mice revealed various roles for orexin neurons in the coordination of emotion, energy homeostasis, reward system, and arousal. For example, orexin neurons are regulated by peripheral metabolic cues, including ghrelin, leptin, and glucose concentration. This suggests that they may provide a link between energy homeostasis and arousal states. A link between the limbic system and orexin neurons might be important for increasing vigilance during emotional stimuli. Orexins are also involved in reward systems and the mechanisms of drug addiction. These findings suggest that orexin neurons sense the outer and inner environment of the body and maintain the proper wakefulness level of animals for survival. This review discusses the mechanism by which orexins maintain sleep/wakefulness states and how this mechanism relates to other systems that regulate emotion, reward, and energy homeostasis.