Fig. 4. (A) ROS production increased in cardiomyocytes cultured under DEPV conditions in a time-dependent manner reaching a peak at 6 hours. DADLE (10 µmol/l) pretreatment inhibited this increase in ROS production at 4, 6 and 8 hours. Values are the mean ± s.d. ^*P<0.05 vs control, ^#P<0.05 vs DEPV. (B) Cardiomyocyte mitochondrial damage was assessed by examining mitochondrial membrane potential, which was determined by the ratio of red and green signals in the micrographs. DEPV-induced depolarization of the mitochondria appeared as a decrease in the red signals with a concomitant increase in the green signals (upper-panel). DADLE (10 µmol/l) inhibited the destruction of mitochondrial membrane potential at 45, 60, 90 and 120 minutes. These effects were blunted by 1 µmol/l glybenclamide (GLY; lower-panel). Values are the mean ± s.d. ^*P<0.05 vs control; ^#P<0.05 vs DEPV; P<0.05 vs DEPV + DADLE. DEPV, serum and glucose deprivation; DADLE, [D-Ala2, D-Leu5]-enkephalin acetate salt.