Paul Waring wrote: > I have been out of touch with the mitochondria field for a few > years. Would anyone care to give me an update on the relative > advantages of JC-1 versus Dioc6 (or other dyes) in measuring > mitochondrial membrane potential ? JC-1 has been found useful for discriminating energized from deenergized mitochondria, but, as far as I know, has never been demonstrated to *measure* mitochondrial potential. The distribution of green vs. red fluorescence is too broad in all directions to make a ratiometric procedure feasible. It is claimed that DiOC6(3) at very low concentrations (around 1 nM) *can* be used for quantitative measurements (Rottenberg H, Wu S: Quantitative assay by flow cytometry of the mitochondrial membrane potential in intact cells. Biochim Biophys Acta 1404:393-404, 1998). I suspect that other cyanines would also work at this low concentration. If the mitochondria are energized, the dye concentration inside will be at least 100 times the external concentration; if the external concentration is much higher than 1 nM, there will be substantial quenching of intramitochondrial dye fluorescence, and also more interference from dye in the cytosol. At the lower concentrations, mitochondrial fluorescence would be expected to track membrane potential. -HowardReceived on Thu Aug 31 14:38:00 2006
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