Pyronin--a fluorescent indicator of membrane potential of the mitochondria. Mechanism of action.

The effect of the functional state of isolated mitochondria on the fluorescence of pyronin added to the suspension is studied. It is shown experimentally that the intensity of fluorescence changes parallel to the degree of energization of the mitochondria. The magnitude and the sign of the fluorescent changes depend on the pyronin/mitochondria ratio and the length of the wave of excitating light. Model experiments show that the effects observed are probably due to the electrophoretic redistribution of pyronin between the medium, the mitochondrial membrane and the matrix, induced by the membrane potential of the mitochondria. It is assumed that pyronin acts as vector fluorescent indicator, similar to anilinonapthalenesulphonate.