The fluorescence of the voltage sensitive dye, diS-C3-(5), has been analyzed by means of synchronous excitation spectroscopy. Using this rather rare fluorescence technique we have been able to distinguish between the slightly shifted spectra of diS-C3-(5) fluorescence from cells and from the supernatant. It has been found that diS-C3-(5) fluorescence in the supernatant can be selectively monitored at lambda exc = 630 nm and lambda em = 650 nm, while the cell associated fluorescence can be observed at lambda exc = 690 nm and lambda em = 710 nm. A modified theory for the diS-C3-(5) fluorescence response to the membrane potential is presented, according to which a linear relationship exists between the logarithmic increment of the dye fluorescence intensity in the supernatant, 1n I/I degrees, and the underlying change in the plasma membrane potential, delta psi p = psi p - psi p degrees. The theory has been tested on human myeloid leukemia cells (line ML-1) in which membrane potential changes were induced by valinomycin clamping in various K+ gradients. It has been demonstrated that the membrane potential change, delta psi p, can be measured on an absolute scale.

Institute of Physics Charles University Prague Czechoslovakia

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J Membr Biol. 1978 Jan 12;38(1-2):73-97 PubMed

J Cell Physiol. 1984 Jul;120(1):83-90 PubMed

Annu Rev Biophys Bioeng. 1979;8:47-68 PubMed

Gen Physiol Biophys. 1984 Feb;3(1):19-30 PubMed

J Physiol. 1974 Jun;239(3):519-52 PubMed

Biophys J. 1980 Jun;30(3):441-62 PubMed

Biochim Biophys Acta. 1982 Dec 30;721(4):341-8 PubMed

J Membr Biol. 1977 May 6;33(1-2):109-40 PubMed

Biochemistry. 1974 Jul 30;13(16):3315-30 PubMed

Methods Enzymol. 1979;55:547-69 PubMed

J Cell Physiol. 1985 Oct;125(1):61-71 PubMed

J Cell Physiol. 1982 Aug;112(2):298-300 PubMed

Gen Physiol Biophys. 1984 Apr;3(2):97-117 PubMed

Biochim Biophys Acta. 1980;595(1):15-30 PubMed

Biosci Rep. 1981 Mar;1(3):183-96 PubMed

Biochim Biophys Acta. 1976 Jun 17;436(2):475-88 PubMed

Methods Enzymol. 1979;55:569-86 PubMed

J Physiol. 1976 Dec;263(2):287-319 PubMed

Monitoring of real changes of plasma membrane potential by diS-C(3)(3) fluorescence in yeast cell suspensions