FOS and obesity due to melanocortin 4 receptor deficiency: For example, introduction of the endocannabinoid receptor ligand, 2-arachidonoyglycerol, into the rat lateral hypothalamus increases REM sleep and c-Fos expression in MCH neurons44 and combined treatment with CB1R and MCH1R antagonists synergistically induces anti-obesity effects in diet-induced obese mice45.