ALTERATION IN RABBIT BRAIN ENDOPLASMIC-RETICULUM CA2-VITRO( TRANSPORTBY FREE OXYGEN RADICALS IN)

The involvement of free oxygen radicals in ischemia-reperfusion injury is generally accepted. We describe here the loss of efficiency of ret icular membranes to sequester Ca2+ due to free oxygen radical damage i n vitro. Based on experimental results we suggest that the primary eff ect of free oxygen radicals is alteration of the lipid component of th e membrane manifested in the increase of passive Ca2+ leak. Prolonged treatment of microsomes with free oxygen radical generating systems al so led to the decrease of Ca2+-ATPase activity which is caused as we s uppose by modulation of the lipid-Ca2+ pump interactions. A protective effect of butylated hydroxytoluene on the depression in the Ca2+ upta ke and Ca2+-ATPase activities supports our suggestions. (C) 1994 Acade mic Press, Inc.