Behavioral correlates of activity in identified hypocretin/orexin neurons.

TitleBehavioral correlates of activity in identified hypocretin/orexin neurons.
Publication TypeJournal Article
Year of Publication2005
AuthorsMileykovskiy BY, Kiyashchenko LI, Siegel JM
Date Published2005 Jun 2
KeywordsAction Potentials, Animals, Electric Stimulation, Exploratory Behavior, Intracellular Signaling Peptides and Proteins, Locus Coeruleus, Male, Neurons, Neuropeptides, Orexins, Rats, Rats, Wistar, Ventral Tegmental Area

Micropipette recording with juxtacellular Neurobiotin ejection, linked micropipette-microwire recording, and antidromic and orthodromic activation from the ventral tegmental area and locus coeruleus were used to identify hypocretin (Hcrt) cells in anesthetized rats and develop criteria for identification of these cells in unanesthetized, unrestrained animals. We found that Hcrt cells have broad action potentials with elongated later positive deflections that distinguish them from adjacent antidromically identified cells. They are relatively inactive in quiet waking but are transiently activated during sensory stimulation. Hcrt cells are silent in slow wave sleep and tonic periods of REM sleep, with occasional burst discharge in phasic REM. Hcrt cells discharge in active waking and have moderate and approximately equal levels of activity during grooming and eating and maximal activity during exploratory behavior. Our findings suggest that these cells are activated during emotional and sensorimotor conditions similar to those that trigger cataplexy in narcoleptic animals.

Alternate JournalNeuron
PubMed ID15924864
Grant ListMH064109 / MH / NIMH NIH HHS / United States
MH071350 / MH / NIMH NIH HHS / United States
NS14610 / NS / NINDS NIH HHS / United States