What is the role of orexin in the brain?

Orexin, also known as hypocretin, is a neuropeptide that plays a crucial role in the regulation of arousal, wakefulness, and appetite. It is primarily produced in the hypothalamus and acts on various parts of the brain to promote wakefulness and maintain alertness. The production of orexin is stimulated during periods of wakefulness, and its levels decrease during sleep. This peptide is particularly important for stabilizing wakefulness and preventing sudden transitions into sleep.

Individuals with low levels of orexin, such as those with narcolepsy, often experience sleep disturbances, highlighting its significance in maintaining wakefulness. Therefore, its primary role is promoting wakefulness rather than inducing sleep, regulating temperature, or facilitating memory storage. These latter functions are managed by different neuropeptides and brain systems.