Metabolic effects of some electrofluorimetric dyes.

The effect of five electrofluorimetric dyes on mitochondrial metabolism was examined to determine their suitability for mitochondrial studies and other biological uses. The dyes merocyanine 540, 8-anilino-1-naphthalene sulfonic acid and bis(1,3-dibutyl barbituric acid-(5))-pentamethane oxonol were found to be inhibitors of the respiratory chain. However, the first two exerted their effect only at high concentrations. 3.3'-Dihexyl-2,2'-oxacarbocyanine was found to act as an uncoupler. 3,3'-Dipropyl-thiocarbocyanine inhibited beta-hydroxybutyrate respiration while dissociating succinate supported respiration from the phosphorylation of ADP. Merocyanine 540 and 8-anilino-1-naphthalene sulfonic acid may be the best suited for studies of membrane potentials in mitochondria since their effect on metabolism is negligible