Ethanol-elicited structural and biochemical alterations in mitochondrial ATPase in cultured myocardial cells

The effects of ethanol (12.5-500 mM for up to 24 h) on mitochondrial structure including that of ATPase particles in cultured ventricular myocardial cells were studied using negative-stain electron microscopy. The activity of mitochondrial ATPase after ethanol treatment was also examined cytochemically and biochemically. At 5 min after the addition of all the concentrations of ethanol examined, some mitochondrial cristae were expanded and the arrangement of mitochondrial ATPase particles on these cristae was disordered. At and after 30 min the cristae decreased in number and some were expanded, vesiculated or fragmented. ATPase particles also decreased in number, particularly after the application of ethanol in concentrations of more than 50 mM. All the mitochondria had broadened and translucent cristae, and lacked ATPase particles with 200 and 500 mM ethanol at 24 h, although with 12.5 and 50 mM ethanol some mitochondria had similar negatively stained images but others had ATPase particles on broadened cristae. The enzymatic activity of the mitochondrial ATPase was unchanged with 200 and 500 mM ethanol at 24 h, compared with controls. The cytochemical technique also detected enzyme activity with all the concentrations of ethanol examined at 24 h. The discrepancy between the structural and biochemical alterations in mitochondrial ATPase induced by ethanol is discussed.