ABSTRACT
The link between hypocretin (Hcrt, orexin) neuropeptides and narcolepsy is now very well documented. Numerous animal models in mice, rats and dogs are available to confirm this relationship (1,2). Human narcolepsy is generally associated with a lack or a great reduction of preprohypocretin mRNA and Hcrt neuropeptides as shown by in situ hybridization (Fig. 1), radioimmunoassay and immunohistochemistry on brain and cerebrospinal fluid samples of narcoleptic patients at all ages (3-5). Based on these observations and the well-documented positive association of human narcolepsy with the human leucocyte antigen markers (6), the current hypothesis suggests that human narcolepsy is an autoimmune disease with hypocretin neurons as the target.
