Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Japan.
Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Japan.
Peptides. 2023 Jul;165:171009. doi: 10.1016/j.peptides.2023.171009. Epub 2023 Apr 11.
Orexin-A and -B (identical to hypocretin-1 and -2) are neuropeptides synthesized in the lateral hypothalamus and perifornical area, and orexin neurons project their axon terminals broadly throughout the entire central nervous system (CNS). The activity of orexins is mediated by two specific G protein-coupled receptors (GPCRs), termed orexin type1 receptor (OX1R) and orexin type2 receptor (OX2R). The orexin system plays a relevant role in various physiological functions, including arousal, feeding, reward, and thermogenesis, and is key to human health. Orexin neurons receive various signals related to environmental, physiological, and emotional stimuli. Previous studies have reported that several neurotransmitters and neuromodulators influence the activation or inhibition of orexin neuron activity. In this review, we summarize the modulating factors of orexin neurons in the sleep/wake rhythm and feeding behavior, particularly in the context of the modulation of appetite, body fluids, and circadian signaling. We also describe the effects of life activity, behavior, and diet on the orexin system. Some studies have observed phenomena that have been verified in animal experiments, revealing the detailed mechanism and neural pathway, while their applications to humans is expected in future research.
食欲素 A 和 B（与下丘脑外侧和穹窿周区的促食欲素 1 和 2 相同）是在外侧下丘脑和穹窿周区合成的神经肽，食欲素神经元的轴突末梢广泛投射到整个中枢神经系统（CNS）。食欲素的活性由两种特定的 G 蛋白偶联受体（GPCR）介导，分别称为食欲素 1 型受体（OX1R）和食欲素 2 型受体（OX2R）。食欲素系统在各种生理功能中发挥着重要作用，包括觉醒、摄食、奖赏和产热，是人类健康的关键。食欲素神经元接收与环境、生理和情绪刺激相关的各种信号。先前的研究报告称，几种神经递质和神经调质会影响食欲素神经元活性的激活或抑制。在这篇综述中，我们总结了睡眠/觉醒节律和摄食行为中调节食欲素神经元的因素，特别是在调节食欲、体液和昼夜信号方面。我们还描述了生活活动、行为和饮食对食欲素系统的影响。一些研究观察到了已在动物实验中得到验证的现象，揭示了详细的机制和神经通路，而这些机制和神经通路有望在未来的研究中应用于人类。
