November 21, 2008

Font Size
A
A
A

Narcolepsy (cont.)

Narcolepsy Causes

Narcolepsy is believed to result from a genetic predisposition and abnormal neurotransmitter (hypocretin, also known as orexin) functioning and sensitivity.

Genetic predisposition

Understanding of narcolepsy stems primarily from research involving narcoleptic dogs (for example, special laboratory-bred Dobermans and Labradors). In these animal models, the disorder is transmitted in an autosomal recessive fashion and is characterized mainly by cataplexy. Only 1% of human cases are inherited and, unlike the canine form, are transmitted in an autosomal dominant manner.

Neurotransmitter

The neurotransmitter hypocretin was identified in the last few years and is strongly associated with narcolepsy in dogs with a genetic predisposition. Hypocretin levels in human subjects with narcolepsy have been found to be undetectable or low in several recent studies of patients with narcolepsy. Hypocretin appears to modulate activity in the hypothalamus (the part of the brain associated with sleep). The deficiency of hypocretin might produce sleep attacks. The drug modafinil (Provigil) is useful in the treatment of narcolepsy is believed to activate hypocretin-containing nerve cells.



Next: Exams and Tests »

Printer-Friendly Format  |  Email to a Friend

Sleep Disorders

Get tips for better sleep.

eMedicineHealth is a first aid and consumer health information site written by physicians for patients and consumers.
WebMD Symptom Checker - Start Here

Snoring Cure Snoring Cure
If you're ready to say goodnight to chronic snoring, a new cure could be right under your nose.See more WebMD Videos »

Adult Skin Problems Slideshow

Search Medical Dictionary