Comparison of cytotoxic effect of sulmazole with ouabain on cultured myocardial cells

Cytotoxic effects of sulmazole (Sul) and ouabain (Oua) were compared in primary cultures of myocardial cells. Lactate dehydrogenase (LDH) release was used as an indicator of cell injury. The results showed that Oua (1 mmol/L) caused severe injury of the cells, which was enhanced by the increased extracellular Ca2+. Sul (0.01, 0.1, and l mmol/L) did not cause injury of the cells in the presence of CaCl2 and rather protected the cells from the injury caused by high extracellular CaCl2. but it caused injury of the cells in the absence of CaC12. In addition, Sul did not cause extra injury in hypoxia and glucose deprivation. The results suggest that Sul is a low cytotoxic cardiotonic drug.