Actelion's research team is targeting the G-Protein coupled receptors, OX1 and OX2, which mediate the actions of orexins.

Orexins are neuropeptide modulators - small protein-like molecules used by nerve cells (or neurons) to communicate with each other in the brain. Orexins act functionally at the interface of alertness, energy homeostasis and reward:aversion systems, essentially to regulate vigilance and alertness states. Defects of the orexin peptides, or their receptors, are associated with wakefulness and sleep disorders.

The anatomical distribution of orexin receptors in the brain supports the essential role that orexin plays in promoting alertness and maintaining wakefulness under situations of high motivational relevance, eg circadian vigilance states, reward opportunities or exposure to threats. Orexins and their receptors are highly conserved across vertebrate species.