oreksiinihypokretiinijärjestelmän

The orexin-hypocretin system is a group of neurons in the hypothalamus that produce neuropeptides called orexin A and orexin B, also known as hypocretins. This system plays a crucial role in regulating sleep-wake cycles, arousal, appetite, and reward-seeking behavior.

Neurons in the lateral hypothalamus and perifornical area synthesize and release orexins, which then act on receptors throughout the brain. The orexin system is intricately linked to other neurotransmitter systems, including those involving dopamine, norepinephrine, serotonin, and acetylcholine, all of which are involved in arousal and wakefulness.

Dysfunction of the orexin-hypocretin system is strongly implicated in narcolepsy, a neurological disorder characterized by excessive daytime sleepiness, cataplexy (sudden loss of muscle tone), sleep paralysis, and hallucinations. In most cases of narcolepsy, there is a significant loss of orexin-producing neurons, leading to a deficiency in orexin signaling. This deficiency disrupts the normal regulation of sleep and wakefulness, resulting in the characteristic symptoms of narcolepsy.

Research into the orexin-hypocretin system has opened new avenues for therapeutic interventions for sleep disorders. Orexin receptor antagonists are being developed as potential treatments for insomnia, while orexin agonists are being investigated for their potential to treat narcolepsy and other sleep-wake disorders. The system's involvement in appetite regulation also suggests potential applications in the treatment of obesity and eating disorders.