Orexins are chemical signals produced in the brain. The area where nerve cells make orexins is called the “hypothalamus”, which is at the base of the brain. This area controls many automatic and hormonal functions. They play a critical role in regulating various functions such as sleep-wake cycles, wakefulness and alertness, and appetite.
When you are awake, orexin neurons are highly active, releasing orexin into their target regions. This promotes arousal, enhances alertness, and helps maintain a state of wakefulness. During rapid eye movement (REM) sleep, the activity of orexin neurons decreases, resulting in less orexin release. When the orexin system doesn’t work correctly, it can contribute to sleep disorders like insomnia and narcolepsy, a condition characterized by excessive daytime sleepiness.
Researchers are exploring ways to manipulate the orexin system with medications to develop treatments for sleep disorders. Disruptions in the orexin system may contribute to difficulties in falling or staying asleep, resulting in insomnia. Research suggests that adjusting orexin receptors could offer a novel approach to promote sleep onset and duration. By blocking orexins effect with medication, researchers hope to help those suffering from insomnia. Conversely, increasing the effect of orexins is likely to benefit conditions with excessive sleepiness such as narcolepsy.
Understanding orexins and how they work is particularly important in sleep disorder research. As researchers unravel the intricate role of orexins in sleep wake regulation, treatments may be developed which better target sleep disorders, specifically insomnia and narcolepsy.
Dr. Mogavero is a neurologist at Vita Salute, San Raffaele University, Milan, Somnologist, Master in Sleep Medicine, and on faculty of the World Sleep Academy.