oligomycins and 3-3--dipropyl-2-2--thiadicarbocyanine

The effects of uncouplers (FCCP, DNF), oligomycin, and rotenone on the fluorescence of potential-sensitive dyes, rhodamine 123 and diS-C3-(5), in lymphocyte suspensions were compared. The fluorescence of these optical probes gradually increased at higher FCCP concentrations. The dependences of fluorescence intensities and FCCP concentrations were similar for both dyes, and only diS-C3-(5) fluorescence started increasing at lower FCCP concentrations. Rotenone (1 microM) significantly increased rhodamine 123 fluorescence. TMPD-induced and uncoupler-induced diS-C3-(5) fluorescence changes increased 1.5- to 2-fold if the incubation mixture was supplemented with oligomycin (0.1-0.2 microgram/ml). The fluorescence responses of the dyes in the lymphocyte suspension correlate with the effects of mitochondrial energetics inhibitors on delta psi m in isolated mitochondria. The results suggest the possibility of using these dyes for estimating the direction of the delta psi m changes in the lymphocyte suspension.

Topics: Animals; Benzothiazoles; Carbocyanines; Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; Energy Metabolism; Female; Fluorescence; Fluorescent Dyes; In Vitro Techniques; Kinetics; Lymphocytes; Membrane Potentials; Mitochondria; Oligomycins; Rats; Rhodamine 123; Rhodamines; Rotenone; Uncoupling Agents

A lipophilic fluorescent cation diS-C3-(5) and rotenone suppress the oxygen consumption rate of thymocytes in similar concentrations. Seventy percent inhibition corresponds to an inhibitor:cytochrome a molar ratio of about 1:1. Addition of uncouplers decreases the inhibition of respiration by diS-C3-(5) (but not rotenone). FCCP in similar concentrations increases O2 consumption in the absence of diS-C3-(5) and the diS-C3-(5) fluorescence intensity in the presence of TMPD in thymocyte suspensions. In most thymocyte preparations, oligomycin (0.05-0.1 microgram/mL) increases the fluorescence of diS-C3-(5) and further addition of TMPD (50-100 microM) decreases the fluorescence. Addition of NaCN (400 microM) after oligomycin leads to a fluorescence increase that is hardly affected by subsequent addition of 0.2 microM FCCP. Nigericin (10-50 nM) decreases the diS-C3-(5) fluorescence. The data indicate that the diS-C3-(5) fluorescence associated with mitochondrial transmembrane potential (delta psi m) may be an essential part of the diS-C3-(5) fluorescence in lymphocyte suspensions. The changes of the diS-C3-(5) fluorescence intensity in the presence of TMPD after FCCP addition reflect delta psi m.

Topics: Animals; Benzothiazoles; Carbocyanines; Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; Ethylenediamines; Fluorescent Dyes; Lymphocytes; Membrane Potentials; Mitochondria; Oligomycins; Oxygen Consumption; Quinolines; Rats; Rotenone; Spectrometry, Fluorescence; Thymus Gland

The cyanine dye 3,3'-dipropyl-2,2'-thiadicarbocyanine iodide [diS-C3(5)] was found to be a potent inhibitor of endogenous respiration of Ehrlich ascites tumor cells. This effect is believed to involve both rotenone and uncoupler type actions of the dye on the electron transport system of the mitochondria.

Topics: Adenosine Triphosphatases; Animals; Benzothiazoles; Carbocyanines; Carcinoma, Ehrlich Tumor; Dinitrophenols; Electron Transport; Fluorides; Kinetics; Mice; Mitochondria; Oligomycins; Oxygen Consumption; Quinolines; Rotenone