Mitochondrial membrane potential in living cells: evidence from studies with rhodamine 6 G as fluorescent probe.

Rhodamine 6 G as a cationic permeant fluorophore is demonstrated to be selectively accumulated by mitochondria of living pancreatic acinar cells from guinea pigs. The accumulation of the fluorescent dye was studied by means of the application of electron transport inhibitors in the respiratory chain, ionophores and some hydrogen donors. Besides, some unspecific staining processes were excluded. Using this technique, it becomes possible to estimate the energy state of living cells under various conditions of energy supply and demand.