Neuronal degeneration in canine narcolepsy

Narcolepsy is a lifelong illness characterized by persistent sleepiness, hy pnagogic hallucinations, and episodes of motor paralysis called cataplexy. We have tested the hypothesis that a transient neurodegenerative process is linked to symptom onset. Using the amino-cupric silver stain on brain sect ions from canine narcoleptics, we round elevated levels of axonal degenerat ion in the amygdala, basal forebrain (including the nucleus of the diagonal band, substantia innominata, and preoptic region), entopeduncular nucleus, and medial septal region. Reactive neuronal somata, an indicator of neuron al pathology, were found in the ventral amygdala. Axonal degeneration was m aximal at 2-4 months of age. The number of reactive cells was maximal at 1 month of age. These degenerative changes precede or coincide with symptom o nset. The forebrain degeneration that we have observed can explain the majo r symptoms of narcolepsy.