Neuropeptide S (NPS) occurs in a great variety of animal species, including humans, and manifests intriguing properties that
make it unique among neurotransmitters, and indeed, among known pharmacological agents. Like hypocretin (orexin), NPS signals
through a GPCR that until recently had remained “orphanized.” And like hypocretin, NPS appears to play a role in the regulation
of sleep/wakefulness. When administered centrally, however, NPS not only promotes wakefulness, but exerts anxiolytic effects.
NPS may thus hold the key to the development of novel drugs to combat symptoms of somnolence without causing anxiogenesis.