Class IV Ca2+ antagonists do not affect lipid peroxidation in singlet oxygen challenged cardiomyocytes.

Abstract The effects of various Ca 2+ antagonists on lipid peroxidation in singlet O 2 -challenged isolated cardiomyocytes from adult rat heart were investigated. Singlet O 2 -challenged untreated cells all hypercontracted as a consequence of Ca 2+ overload and produced 463.6 ± 143.6 nM malondialdehyde (MDA; mean ± SD, n = 8). Protective Ca 2+ antagonists reduced the amount of damaged cells, but did generally not affect MDA production. On the other hand, free radical scavengers and antioxidants displayed a good correlation between number of protected cells and MDA produced. It is concluded that flunarizine-like Ca 2+ antagonists protect cells against Ca 2+ overload without, however, interfering with peroxidative processes.