title: Distribution of neurochemical abnormalities in patients with narcolepsy with cataplexy: An in vivo brain proton MR spectroscopy study.
abstract: Narcolepsy with cataplexy is characterised by excessive daytime sleepiness, sudden drops of muscle tone triggered by emotions, termed cataplexy, disrupted nocturnal sleep and other dissociated rapid eye movement (REM) sleep phenomena. Narcolepsy has been linked to a loss of hypothalamic neurons producing hypocretins, neuropeptides implicated in the regulation of the arousal system. Neuroimaging and neurometabolic studies have shown the pathophysiological involvement of other brain structures such as cerebral cortex and thalamus, but, overall with inconsistent results. We investigated, by using an advanced quantitative MR technique, proton MR spectroscopy ((1)H-MRS), the distribution of brain neurochemical abnormalities in narcolepsy with cataplexy patients. Single voxel (1)H-MRS study was performed in the thalamus, hypothalamus, and parietal-occipital cortex of hypocretin deficient, narcolepsy with cataplexy patients, HLA-DQB1*0602-positive, drug free. No significant changes were detected in the thalamus and parietal-occipital cortex of the patients. On the other hand, the neuronal marker N-acetyl-aspartate was reduced in the hypothalamus of narcolepsy with cataplexy patients compared to controls. These (1)H-MRS findings further support that in narcolepsy with cataplexy patients, the hypothalamus is the primary site of neural lesions. The absence of (1)H-MRS neurodegenerative changes in the thalamus and cerebral cortex suggests that the abnormalities detected in these brain regions by other neuroimaging techniques are likely of functional nature.
authors.affiliation: MR Spectroscopy Unit, Department of Internal Medicine, Aging and Nephrology, University of Bologna, Bologna, Italy. caterina.tonon@unibo.it
authors.forename: Caterina
authors.initials: C
authors.lastname: Tonon
authors.forename: Christian
authors.initials: C
authors.lastname: Franceschini
authors.forename: Claudia
authors.initials: C
authors.lastname: Testa
authors.forename: David Neil
authors.initials: DN
authors.lastname: Manners
authors.forename: Francesca
authors.initials: F
authors.lastname: Poli
authors.forename: Barbara
authors.initials: B
authors.lastname: Mostacci
authors.forename: Emanuel
authors.initials: E
authors.lastname: Mignot
authors.forename: Pasquale
authors.initials: P
authors.lastname: Montagna
authors.forename: Bruno
authors.initials: B
authors.lastname: Barbiroli
authors.forename: Raffaele
authors.initials: R
authors.lastname: Lodi
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Plazzi
mesh_terms: D000328:Adult; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D001921:Brain / Q000378:metabolism / Q000502:physiology*; D001931:Brain Mapping; D016923:Cell Death; D005260:Female; D006801:Humans; D007031:Hypothalamus / Q000378:metabolism / Q000502:physiology; D007091:Image Processing, Computer-Assisted; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D009290:Narcolepsy / Q000378:metabolism* / Q000503:physiopathology; D009474:Neurons / Q000378:metabolism / Q000502:physiology
chemical_list: D001224:Aspartic Acid; C000179:N-acetylaspartate