Orexin receptor antagonists are used for the treatment of insomnia (Cox et al., 2010); therefore, the antagonistic activity of A2ARPAM-1 and A2ARPAM-2 against human orexin A (OXA) at orexin-1 receptors (OX1Rs) and orexin-2 receptors (OX2Rs) was measured in a cell-based calcium assay. Here, HCRT is linked to insomnia.