These data suggest that Hcrt/Orx2R is critical for normal regulation of wakefulness/non-REM transitions, whereas the intense deregulation of REM sleep control present in the narcoleptic syndrome relies on signaling disruption through both Hcrt/Orx1R and Hcrt/Orx2R. This evidence concerns the gene HCRT and narcolepsy-cataplexy syndrome.