image: Pair of Doberman pinschers playing (top); seconds later they have a narcoleptic attack (bottom).
The five-year-old dog's fits cause her to suddenly fall asleep at any time. Her bouts of unconciousness last between four and 20 seconds and are brought on by situations during which she becomes excited, such as the daily arrival of the postman, playing with other dogs or if she is petted too vigourously. Her owner has learnt to recognise the signs leading to Mable's sleep attacks. She wags her tail furiously and runs around yelping before she hits the ground "like she's been struck by a bullet," owner Trevor Gliddon, 46, said. Vets have recommended Mable avoids over-excitement in a bid to beat the sleeping bouts. To keep her calm, Trevor uses a number of techniques, including places his hands over Mable's ears to block out exciting sounds or calling her name sharply to draw her attention away from the stimulus. However, Trevor is not always successful in shielding Mable from the excitement of meeting fellow dogs. "Mable does get excited when she meets other dogs because she's so friendly," said Trevor. "Then all of a sudden she'll be out like a light.
via Video: Narcoleptic dog drops unconscious at arrival of postman -
Mable's problem is as uncommon as you might think. I found several Youtube videos of narcoleptic dogs: Skeeter, Rusty, Sampson, Snoozy ... and the cause is not so mysterious. There is a paper from 1999 is titled, "The Sleep Disorder Canine Narcolepsy Is Caused by a Mutation in the Hypocretin (Orexin) Receptor 2 Gene". Hypocretins, discovered in 1998 by De Lecea, are neuro exciters localized in the synaptic vesicle. A defect in the Hcrtr2 gene disturbs a major neuromodulator of sleep. Mutations in the HCRTR2 gene or other hypocretin genes could explain hereditary human narcolepsy.
... researchers at the University of California, Los Angeles, found that patients with narcolepsy have a dramatic and degenerative loss of the brain cells containing hypocretin. The reason for this loss is still a mystery. Mignot suspects that the death of hypocretin-producing cells may come from an autoimmune condition. New medicine would bring relief to many with this disorder, which affects about 135,000 people in the United States.