CONTEXT Narcoleptic patients with cataplexy have a general loss of hypocretin (orexin) in the lateral hypothalamus, possibly due to an autoimmune-mediated degeneration of the hypocretin neurons. In addition to excessive daytime sleepiness, Prader-Willi syndrome (PWS) patients may show narcolepsy-like symptoms, such as sleep-onset rapid eye movement sleep and cataplexy, independent of obesity-re...

As is evident from the pathological consequences of its absence in narcolepsy, orexin (hypocretin) appears to be critical for the maintenance of wakefulness. Via diffuse projections through the brain, orexin-containing neurons in the hypothalamus may act on a number of wake-promoting systems. Among these are the intralaminar and midline thalamic nuclei, which project in turn in a widespread man...

A recent publication suggested that hypocretin (Hcrt, orexin) may mediate the neuropathological process leading to Alzheimer’s disease (AD) and that antagonism of hypocretin receptors decreases this process. Narcoleptics have an approximately 90% loss of Hcrt neurons and commensurate reductions in the levels of Hcrt in their cerebrospinal fluid beginning at disease onset, usually before the age...

Orexin is produced exclusively in the lateral hypothalamus, where it is known to be involved in pain modulation through brain stem. Due to the important role of this peptide in functions such as eating, sleeping and awaking, addiction, it attracted the attention of researchers in medical sciences specially neuroscientists. These hypothalamic peptides play a critical role in arousal in s...

Recent work has implicated the hypocretin (orexin) system in the genesis of narcolepsy. In the current study we demonstrate that systemically administered hypocretin-1 (Hcrt-1) produces an increase in activity level, longer waking periods, a decrease in REM sleep without change in nonREM sleep, reduced sleep fragmentation and a dose dependent reduction in cataplexy in canine narcoleptics. Repea...