Since long-term sleep loss is a critical risk factor that may lead to metabolic disorders such as obesity and diabetes and the hypocretin system is a critical player in the regulation of metabolic functions of the brain (Copinschi et al., 2014; St-Onge and Shechter, 2014), we examined the effects of a chronic exposure to reduced sleep on the hypocretin system in mice through applying modafinil daily to mice during the light phase for a week (Rao et al., 2007). This evidence concerns the gene HCRT and obesity due to melanocortin 4 receptor deficiency.