The regulation of sleep and wakefulness by the hypothalamic neuropeptide orexin/hypocretin
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Updated: May 12, 2026

Optogenetic Manipulation of Neural Circuits During Monitoring Sleep/wakefulness States in Mice
Published on: June 19, 2019
Ayumu Inutsuka1, Akihiro Yamanaka
1Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.
Abstract:
Orexins, also known as hypocretins, are neuropeptides that are exclusively expressed by neurons in the lateral hypothalamic area. Although originally recognized as regulators of feeding behavior, orexins are now mainly regarded as key modulators of the sleep/wakefulness cycle. In addition, anatomical studies of neural networks and analyses of transgenic mice have revealed integrated roles for orexin neurons in the coordination of emotion, energy homeostasis, and the reward system. A functional link between the limbic system and orexin neurons may be important for increasing vigilance in response to emotional stimuli. These findings suggest that orexin neurons relay information about an organism's environment to maintain the proper amount of sleep and wakefulness in animals.
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