Neuropeptide system, centered in dorsolateral hypothalamus, that regulates arou sal states, influences feeding, and plays a role in sleep disorder narcolepsy. Hypocretin aka orexin system: also influences hormone secretion and autonomic h omeostasis. Most human narcolepsies result from autoimmune attack against hypocretin-produc ing neurons. Discovery of a neuropeptide system that regulates arousal states and energy met abolism. Hypocretins aka orexins are 2 carboxy-terminally amidated neuropeptides of rela ted sequence. They"re produced from a common precursor, which is expressed only in a few thou sand neurons of rat dorsolateral hypothalamus. 2 g protein coupled receptors (gpcrs) for hypocretins have been id"d, they have diff distrubution w/i cns and diff affinities for the 2 hypocretins. Hypocretins (h) detected in secretory vesicles at synapses of fibers that proje ct to areas w/i posterior hypothalamus that are implicated in feeding behaviours & hormone secretion.