Acute effects of ethanol on cultured myocardial cells: an ultrastructural study

Myocardial cells in monolayer culture were examined ultrastructurally at various times (5 min-24 hr) after addition of ethanol (12.5-500 mM). At 5 min, all concentrations of ethanol induced mitochondrial fusion and a remarkable increase in glycogen granules, and the mitochondrial outer membrane seemed more fragile. These initial ultrastructural changes then recovered with time. Glycogen granules were decreased, then returned to normal more rapidly as the ethanol concentration was increased. Mitochondrial fusion and fragile appearance of the outer membrane were hardly seen at 1 hr in the presence of 12.5 or 50 mM ethanol, but were still evident with higher ethanol concentrations (200 and 500 mM), though less frequently than at 5 and 30 min. Furthermore, 'giant mitochondria' (with at least a five-fold increase in sectional area) appeared in the presence of 200 and 500 mM ethanol with increasing time of exposure. These results are discussed in relation to the direct effects of ethanol.