[Antioxidant-induced release of calcium in biological membranes]

The effect of synthetic (BHT, 2,2,5,7,8-pentamethyl-6-hydroxychroman) and natural (alpha-tocopherol) antioxidants on Ca++-transporting systems was compared in platelets, brain synaptosomes, and skeletal muscle sarcoplasmic reticulum. It was shown that synthetic antioxidants, in contrast to alpha-tocopherol, induced Ca++-release manifested in platelet aggregation, stimulation of 5-hydroxytryptamine release by synaptosomes, synaptosome depolarization and inhibition of Ca++-transport and Ca++-ATPase activity in the sarcoplasmic reticulum. The disturbances of Ca++-homeostasis induced by synthetic antioxidants are considered as molecular mechanisms of complications encountered upon their application.