Sleep regulation molecules involved

The orexin receptors (0X1R and 0X2R) are G-protein coupled receptors expressed mainly in the brain. These receptors are believed to be involved in the regulation of the sleep-wake cycle and other behaviors in animals and humans. Activation of these two receptors by two endogenous peptides, orexin A and orexin B, promotes wakefulness in animals. Hence, blockade of orexin signaling by a small molecule antagonist may offer a new treatment for insomnia patients. Clinical evidence for this hypothesis was demonstrated in 2007 with the release of data from a Phase II insomnia trial from Actelion Pharmaceuticals (1). 

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