EFFECTS OF IRON-INDUCED LIPID-PEROXIDATION AND OF ACIDOSIS ON CHOLINE UPTAKE BY SYNAPTOSOMES

The effects of iron-induced lipid peroxidation and of lactic acidosis on [H-3]choline uptake were investigated on crude synaptosomes prepared from rat cerebral cortices. Fe2+-induced lipid peroxidation as evidenced from the production of thiobarbituric acid reactives substances (TBARS) was correlated with a decrease in high-affinity choline uptake (HACU). Trolox C, a free radical scavenger, prevented both Fe2+-induced TBARS production and decrease in HACU. Lactic acidosis (pH 6.0 for 30 or 60 min) increased the TBARS production with concomitant decrease in HACU (-48%, -78%, respectively). The acidosis dependent decrease was not reversible following pH 7.4 readjustment after 60 min acidosis. It was not prevented by trolox C, although trolox C inhibited the acidosis-induced production of TBARS. The results suggest that the contribution of acidosis to peroxidative damages is probably of less importance in comparison to other cytotoxic mechanisms.