Stabilizing effect of antioxidants and inhibitors of prostaglandin synthesis on after-contractions in Ca2+-overloaded myocardium.

Ca2+ overload followed by after-contractions was induced by perfusion of mammalian papillary muscles with O-K0+, high Ca2+ solution. The effect of lipotrophic agents (dexamethasone, indomethacin) or free radical scavengers (alpha-tocopherol, reduced glutathione, synthetic antioxidant) was tested at different stages of Ca2+ overloading processes. All the agents tested proved to be effective in attenuating the after-contractions. Activation of lipid peroxidation has been suggested as one of the possible molecular events underlying mechanical destabilization of Ca2+-overloaded myocardium.