Loss of neurons Orexin, otherwise known as hypocretin, is a neuropeptide that acts within the brain to regulate appetite and wakefulness as well as a number of other cognitive and physiological processes. Loss of these orexin-producing neurons causes<unk>  and most individuals with<unk>  have a reduced number of these neurons in their brains. Selective destruction of the HCRT/OX neurons with preservation of proximate structures suggests a highly specific autoimmune pathophysiology. Cerebrospinal fluid HCRT-1/OX-A is undetectable in up to 95% of patients with type 1<unk> . The system which regulates sleep, arousal, and transitions between these states in humans is composed of three interconnected subsystems: the orexin projections from the lateral hypothalamus, the reticular activating system, and the ventrolateral preoptic nucleus. In narcoleptic individuals, these systems are all associated with impairments due to a greatly reduced number of hypothalamic orexin projection neurons and significantly fewer orexin neuropeptides in cerebrospinal fluid and neural tissue, compared to non-narcoleptic individuals. Those with<unk>  generally experience the REM stage of sleep within five minutes of falling asleep, while people who do not have<unk>  (unless they are significantly sleep deprived) do not experience REM until after a period of slow-wave sleep, which lasts for about the first hour or so of a sleep cycle. Disturbed sleep states The neural control of normal sleep states and the relationship to<unk>  are only partially understood. In humans, narcoleptic sleep is characterized by a tendency to go abruptly from a waking state to REM sleep with little or no intervening non-REM sleep. The changes in the motor and proprioceptive systems during REM sleep have been studied in both human and animal models. During normal REM sleep, spinal and brainstem alpha motor neuron hyperpolarization produces almost complete atonia of skeletal muscles via an inhibitory descending reticulospinal pathway. Acetylcholine may be one of the neurotransmitters involved in this pathway. In<unk> , the reflex inhibition of the motor system seen in cataplexy has features normally seen only in normal REM sleep.
Narcolepsy
Heart failure
Erotolepsy
Major depressive disorder
Nicotine withdrawal
Anemia
Dancing mania
Sleep apnea