Lateral hypothalamus an OX1-induced CB1 pressor response in the rostral ventrolateral medulla. Narcolepsy is associated with a marked reduction in the number of orexinergic projection neurons from the lateral hypothalamus and very low orexin peptides in cerebrospinal fluid. This has been identified as the mechanism responsible for narcoleptic symptoms. Evidence suggest that OX1 neurons that synapse onto the dorsal nucleus of the vagus nerve and parts of the brain stem may play a role in the pathophysiology of chronic pain and visceral hypersensitivity in functional gastrointestinal disorders. Lateral hypothalamus The lateral hypothalamus, also called the lateral hypothalamic area, contains the primary orexinergic
Lateral hypothalamus substructures, including the rostral ventromedial medulla, rostral ventrolateral medulla, nucleus ambiguus, solitary nucleus, spinal trigeminal nucleus, pontine micturition center, ventral respiratory group, and pontine respiratory group), area postrema, and dorsal nucleus of vagus nerve. Cannabinoid receptor 1 (CB1) is colocalized on orexinergic projection neurons in the lateral hypothalamus and many output structures, where the CB1 and orexin receptor 1 (OX1) receptors physically and functionally join together to form the CB1–OX1 receptor heterodimer. There is substantial anatomical and functional overlap and systemic cross-talk between the endocannabinoid system and orexin system within the central nervous system. Through the diverse outputs of the