Through the diverse outputs of the orexin system, the orexin neurons in the<unk>  mediate an array of functions. Two of the most commonly noted functions of orexin peptides in the<unk>  are the promotion of feeding behavior and arousal (i.e., wakefulness). More generally, the orexinergic neural projections of the<unk>  are involved in thermoregulation, regulating gastrointestinal motility and gastrointestinal function by way of the dorsal nucleus of the vagus nerve, reducing pain and nociception through several output structures (e.g., periaqueductal gray matter), modulating the rewarding property of stimuli through the ventral tegmental area projections and other outputs in the reward system, regulating energy homeostasis and neuroendocrine functions (e.g., HPA axis, HPG axis, and HPT axis) through other hypothalamic outputs, and regulating visceral functions (e.g., respiration, blood pressure, and urination) via a group of structures in the brain stem, among other functions. The endocannabinoid system and the orexin system mediate many of the same cognitive and physical effects, and a significant overlap in their function and localization has been noted in a 2013 medical review; the receptor heterodimer produces a 100-fold amplification of the potency of the orexin receptor 1-mediated ERK pathway signaling. Unique functional interactions have been noted as well, such as an OX1-induced CB1 pressor response in the rostral ventrolateral medulla.
Lateral hypothalamus
Preoptic anterior hypothalamus
Putamen
Postrhinal cortex
Isothalamus
Pretectal area
Periventricular nucleus
Fusiform body area