INTERACTION OF DIS-C-3-(5) WITH DNP AND P ALMITIC ACID DURING STUDYING THE TRANSMEMBRANE MITOCHONDRIAL POTENTIALS BY THE METHOD OF PENETRATING IONS

Fluorescent potential-sensitive dye diS-C-3-(5) has been used as a per meating lipophilic cation to observe the changes in Delta psi across r at liver mitochondrial membranes by the method of penetrating ions. Si milarly to TPP+, the dye concentration in the medium during organella energization decreased, and the potential difference across membrane-e lectrode (U-meas) increased. The drop in U-meas upon mitochondria deen ergization unequivocally indicates the diS-C-3-(5) release into surrou nding solution. At 0.3-0.6 mu M concentrations, diS-C-3-(5) does not u ncouple mitochondria as far as it was possible to observe from the rev ersible Delta psi, decrease during ADP phosphorylation. In contrast to TPP+, only qualitative observations of Delta psi changes can be made using diS-C-3-(5) because this dye binds not only to membranes but to uncouplers (DNP and palmitic acid) and the cell in which investigation s are carried out.