Fig. 5. Effect of exposure of cultures to iron with or without isoflurane exposure on mitochondrial membrane potential. Cultures were pretreated with 10 μm 5,5’,6,6’-tetrachloro-1,1’,3,3’-tetraacethylbenzimidazolylcarbocyamine iodide (JC-1) for 30 min, washed, and then exposed to iron or iron plus isoflurane. Fluorescence was measured at either 20 min after onset of iron or iron-plus-isoflurane exposure (Intra Exposure) or 6 h after completion of a 30-min exposure (6 h Post Exposure) at two sets of excitation–emission wavelengths (485–530 nm and 530–590 nm). The ratio of fluorescence intensity measured at each wavelength was calculated as mitochondrial membrane polarization. Higher ratios indicate depolarization of the mitochondrial inner membrane. Cont. = untreated control cultures; Fe = 300 μm FeSO⁴–FeCl³; Fe + Iso = 300 μm FeSO⁴–FeCl³+ 1.2 mm isoflurane. Values are mean ± SD. ^aP  less than 0.01 versus  untreated controls; ^bP  less than 0.01 versus  Fe. N = 16 culture wells per condition. Cont. + DNP = effects of 500 μm dinitrophenol (a potent uncoupler of oxidative phosphorylation).