Plasma glutamate and glycine levels in patients with amyotrophic lateral sclerosis.
Defective glutamate (Glu) metabolism and glutamate excitotoxicity have been implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS). Glycine (Gly), the main inhibitory neurotransmitter, has been shown to potentiate excitatory transmission. In the present study, the levels of Glu and Gly in fasting plasma were measured by high performance liquid chromatography (HPLC) in 20 healthy volunteers and in 65 untreated ALS patients. Increased plasma Glu levels were observed in ALS (p=0.05), correlating with longer disease duration (p=0.03, beta=0.34) and male gender (p=0.02). Furthermore, the increase was found only in the spinal subtype of the disease (p=0.03), while in the bulbar subtype, no significant increase was noted. As regards plasma Gly, no difference was observed between patients and controls; however female patients had higher levels than males. The above results are compatible with the "glutamate hypothesis" of ALS and suggest that the spinal and bulbar-onset subtypes of the disease may be biochemically different.
Andreadou
Elisabeth
E
Department of Neurology, Athens National University, Aeginition Hospital, Athens, Greece. eandread@med.uoa.gr
Kapaki
Elisabeth
E
Kokotis
Panagiotis
P
Paraskevas
George P
GP
Katsaros
Nikolaos
N
Libitaki
Georgia
G
Petropoulou
Olga
O
Zis
Vassilios
V
Sfagos
Constantinos
C
Vassilopoulos
Demetrios
D
D000690:Amyotrophic Lateral Sclerosis / Q000097:blood* / Q000175:diagnosis / Q000503:physiopathology; D002851:Chromatography, High Pressure Liquid; D005260:Female; D005508:Food Deprivation; D018698:Glutamic Acid / Q000097:blood*; D005998:Glycine / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index
D018698:Glutamic Acid; D005998:Glycine