Orexin and MCH neurons double ablated mice showed severe sleep attack and cataplexy

摘要

Orexin and MCH neurons double ablated mice showed severe sleep attack and cataplexy The lateral hypothalamus (LH) is implicated in the regulation of instinctive behavior, including sleep and wakefulness. Orexin- producing neurons (orexin neurons) and melanin-concentrating hormone (MCH)-producing neurons (MCH neurons) are exclusively distributed in the LH and projected to whole brain to regulate sleep and wakefulness. Ablation of orexin neurons decreased wakeful- ness in the dark period and resulted in narcolepsy, but ablation of MCH neurons increased wakefulness. These indicated that orexin and MCH neurons were important but play a different role in the regulation of sleep/wakefulness. Reciprocal innervation between orexin and MCH neurons in vitro has been reported. Orexin neu- rons innervate and inhibited MCH neurons. On the other hand, application of MCH peptides inhibited the firing rate in orexin neurons. Nevertheless, it is unclear how the interactions between orexin and MCH neurons affect sleep/wakefulness. To understand the functional interaction between orexin and MCH neurons and its regulation of sleep/wakefulness, we generated transgenetic mice in which both orexin and MCH neurons are ablated by the Tet- off system. These double ablation mice increased wakefulness and.