THE ALTERATIONS IN THE ENERGY-LINKED PROPERTIES INDUCED IN RAT-LIVER MITOCHONDRIA BY ACETYLSALYCILATE ARE PREVENTED BY CYCLOSPORINE-A OR MG2+

The alterations in rat liver mitochondria induced by acetylsalicylate in the presence of low concentrations of Ca2+ (large amplitude swellin g, permeability to [C-14]sucrose, collapse of transmembrane potential and effluxes of endogenous Mg2+ and accumulated Ca2+) were fully preve nted by either cyclosporin A or Mg2+. Cyclosporin A and Mg2+ were also capable of restoring transmembrane potential upon its decrease induce d by acetylsalicylate. The loss of endogenous Mg2+ was the primary eff ect promoted by acetylsalicylate; the other noxious effects followed. These results indicate that Mg2+ are fundamental components of the mit ochondrial permeability barrier and that their loss might be responsib le for the membrane transition induced by acetylsalicylate.