M. Miele et al., Glutamate and catabolites of high-energy phosphates in the striatum and brainstem of young and aged rats subchronically exposed to manganese, AGING-CLIN, 12(5), 2000, pp. 393-397
Citations number
28
Categorie Soggetti
General & Internal Medicine","Medical Research General Topics
The degradation of high-energy phosphates was recently shown to precede man
ganese-induced cellular death. We evaluated hypoxanthine, xanthine, uric ac
id and glutamate levels in the striatum and brainstem of 3- and 20-month-ol
d rats after subchronic oral exposure to manganese (MnCl2, 200 mg/kg/day in
young rats, and 50-100 or 200 mg/kg/day in aged rats). Aged rats had highe
r basal levels of hypoxanthine, xanthine, and glutamate both in the striatu
m and brainstem than young rats; conversely, basal uric acid levels were lo
wer in the striatum, but higher in the brainstem. Manganese induced a signi
ficantly greater increase in hypoxanthine, xanthine, uric acid and glutamat
e levels in aged rats than in young rats in both brain regions. These findi
ngs depict a greater manganese-induced energetic impairment (increases in h
ypoxanthine and xanthine levels), xanthine oxidase-induced free radical gen
eration (increases in xanthine and uric acid levels), and excitotoxic statu
s (increases in glutamate levels) in aged rats than in young rats. In addit
ion, these findings may also account for a greater manganese toxicity to th
e nigro-striatal dopaminergic system in aged than in young rats, as shown i
n a previous work. (C)2000, Editrice Kurtis.