Orexin peptides activate orexin 1 and orexin 2 receptors (OX(1)R and OX(2)R), regulate locomotion and sleep-wake. The dual OX(1)R/OX(2)R antagonist almorexant reduces activity and promotes sleep in multiple species, including man. The relative contributions of the two receptors in locomotion and sleep/wake regulation were investigated in mice.
Mang, G. M., Dürst, T., Bürki, H., Imobersteg, S., Abramowski, D., Schuepbach, E., … Gee, C. E. (2012). The Dual Orexin Receptor Antagonist Almorexant Induces Sleep and Decreases Orexin-Induced Locomotion by Blocking Orexin 2 Receptors. Sleep, 35(12), 1625–1635. https://doi.org/10.5665/sleep.2232