[Neuroanatomic bases of hypocretin actions on the ascending reticular activating system: a contribution to narcolepsy physiopathology].

The present study describes at the ultrastructural level the hypocretinergic innervation of brainstem reticular formation neurons that project to the medial frontal cortex in the rat. In addition, we assess, by using dual immunofluorescence techniques, the proportion of those reticular neurons containing specific neurotransmitters. Our results indicate that hypocretinergic axons make asymmetric synapses with neurons within the locus coeruleus, ventral tegmental area, dorsal raphe nucleus and laterodorsal tegmental nucleus that target the medial frontal cortex, Hypocretins could facilitate wakefulness and cortical activation, therefore, by activation of those neurons with cortical projections in these four reticular nuclei.