title: Undesirable feature of safranine as a probe for mitochondrial membrane potential.
abstract: This communication describes experiments showing that safranine, at the concentrations usually employed as a probe of mitochondrial membrane potential, causes significant undesirable side effects on Ca2+ transport by liver mitochondria. The major observations are: (i) safranine potentiates the spontaneous Ca2+ release from liver mitochondria induced by phosphate or acetoacetate. This is paralelled by potentiation of the release of state-4 respiration and of the rate of mitochondrial swelling, indicating a generalized effect of the dye on the mitochondrial membrane; (ii) the efflux of mitochondrial Ca2+ stimulated by hydroperoxide is irreversible in the presence of safranine even if membrane stabilizers such as Mg2+ and ATP are present. It is concluded that the use of safranine to monitor the changes in membrane potential during Ca2+ transport by mitochondria should be avoided or special care be taken.
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism; D008274:Magnesium / Q000378:metabolism; D008297:Male; D008564:Membrane Potentials; D008928:Mitochondria / Q000502:physiology*; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism; D008933:Mitochondrial Swelling / Q000187:drug effects; D010101:Oxygen Consumption / Q000187:drug effects; D010619:Phenazines / Q000009:adverse effects; D051381:Rats
chemical_list: D010619:Phenazines; D000255:Adenosine Triphosphate; D008274:Magnesium; D002118:Calcium; C009195:safranine T