title: Locus coeruleus neurons: cessation of activity during cataplexy.
abstract: Cataplexy, a symptom of narcolepsy, is a loss of muscle tone usually triggered by sudden, emotionally significant stimuli. We now report that locus coeruleus neurons cease discharge throughout cataplexy periods in canine narcoleptics. Locus coeruleus discharge rates during cataplexy were as low as or lower than those seen during rapid-eye-movement sleep. Prazosin, an alpha1 antagonist, and physostigmine, a cholinesterase inhibitor, both of which precipitate cataplexy, decreased locus coeruleus discharge rate. Our results are consistent with the hypothesis that locus coeruleus activity contributes to the maintenance of muscle tone in waking, and that reduction in locus coeruleus discharge plays a role in the loss of muscle tone in cataplexy and rapid-eye-movement sleep. Our results also show that the complete cessation of locus coeruleus activity is not sufficient to trigger rapid-eye-movement sleep in narcoleptics.
authors.affiliation: Neurobiology Research, VA Medical Center, North Hills, CA 91343, USA.
authors.forename: M F
authors.initials: MF
authors.lastname: Wu
authors.forename: S A
authors.initials: SA
authors.lastname: Gulyani
authors.forename: E
authors.initials: E
authors.lastname: Yau
authors.forename: E
authors.initials: E
authors.lastname: Mignot
authors.forename: B
authors.initials: B
authors.lastname: Phan
authors.forename: J M
authors.initials: JM
authors.lastname: Siegel
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D002385:Cataplexy / Q000503:physiopathology*; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D004285:Dogs; D004594:Electrophysiology; D008125:Locus Coeruleus / Q000187:drug effects / Q000473:pathology / Q000502:physiology / Q000503:physiopathology*; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D010830:Physostigmine / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D012895:Sleep, REM / Q000502:physiology
chemical_list: D000317:Adrenergic alpha-Antagonists; D002800:Cholinesterase Inhibitors; D010830:Physostigmine; D011224:Prazosin