HCRT and narcolepsy: In animal models, the loss of the hypocretin peptide, its receptors (particularly OX2R) or hypocretin-containing neurons results in a narcolepsy-like phenotype (Chemelli et al., 1999; Lin et al., 1999; Hara et al., 2001; Yamanaka et al., 2003; Willie et al., 2003).