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Cytoplasmic calcium mediates oxidative damage in an excitotoxic /energetic deficit synergic model in rats
Author(s) -
PérezDe La Cruz Verónica,
Konigsberg Mina,
PedrazaChaverri José,
HerreraMundo Nieves,
DíazMuñoz Mauricio,
Morán Julio,
Fortoulvan der Goes Teresa,
RondánZárate Adrián,
Maldonado Perla D.,
Ali Syed F.,
Santamaría Abel
Publication year - 2008
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.2008.06088.x
Subject(s) - chemistry , excitotoxicity , calcium , dizocilpine , lipid peroxidation , pharmacology , biochemistry , oxidative stress , bapta , calcium in biology , extracellular , nmda receptor , intracellular , biology , receptor , organic chemistry
Excessive calcium is responsible for triggering different potentially fatal metabolic pathways during neurodegeneration. In this study, we evaluated the role of calcium on the oxidative damage produced in an in vitro combined model of excitotoxicity/energy deficit produced by the co‐administration of quinolinate and 3‐nitropropionate to brain synaptosomal membranes. Synaptosomal fractions were incubated in the presence of subtoxic concentrations of these agents (21 and 166 µ m , respectively). In order further to characterize possible toxic mechanisms involved in oxidative damage in this experimental paradigm, agents with different properties – dizocilpine, acetyl l ‐carnitine, iron porphyrinate and S‐allylcysteine – were tested at increasing concentrations (10–1000 µ m ). Lipid peroxidation was assessed by the formation of thiobarbituric acid‐reactive substances. For confirmatory purposes, additional fractions were incubated in parallel in the presence of the intracellular calcium chelator 1,2‐bis(2‐aminophenoxy)ethane‐N,N,N′,N′‐tetraacetic acid‐acetoxymethyl ester (BAPTA‐AM). Under physiological conditions of extracellular calcium availability, synaptomes exposed to both toxins displayed an increased lipoperoxidation (76% above controls), and this effect was partially attenuated by the tested agents as follows: dizocilpine = iron porphyrinate > acetyl l ‐carnitine > S‐allylcysteine. When the incubation medium was deprived of calcium, the lipoperoxidative effect achieved in this experimental paradigm was still high (49% above the control), and the order of attenuation was: iron porphyrinate > S‐allylcysteine > acetyl l ‐carnitine > dizocilpine. BAPTA‐AM was effective in preventing the pro‐oxidant action of both toxins, promoting even lower peroxidative levels than those quantified under basal conditions. Our results suggest that the lipid peroxidation induced in synaptosomal fractions by quinolinate plus 3‐nitropropionate is largely dependent on the cytoplasmic concentrations of calcium.