Mitochondrial membrane potential and hydroethidine‐monitored superoxide generation in cultured cerebellar granule cells
Year: 1997
Type: article
Abstract: Mitochondrial depolarisation has been reported to enhance the generation of superoxide anion (O2.-) in a number of cell preparations while an inhibition has been observed with isolated mitochondria. Cerebellar granule cells equilibrated with > 1 microM hydroethidine (dihydroethidium) which is oxidised to the fluorescent ethidium cation by O2.- showed a large increase in fluorescence on protonophore addition. However, controls showed the fluorescent enhancement to be a consequence of release of unbound preformed ethidium from the mitochondrial matrix within the cell with resultant fluorescent enhancement. This ambiguity was removed by the use of low (1 microM) concentrations of dye in which case generated ethidium remained bound within the mitochondria. Under these conditions antimycin A, but not protonophore addition, produced an increase in fluorescence. It is concluded that excess ethidium acts as an indicator of mitochondrial membrane potential obscuring the monitoring of O2.- and that certain experiments employing this indicator in cells may require re-evaluation.
Source: FEBS Letters
Institution: University of Dundee
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: bronze
Funders: Wellcome Trust, Medical Research Council
OpenAlex ID: W1981783025