Preservation of Mitochondrial Membrane Potential During Anoxia

Abstract

Mitochondria (Mt) in living cells can be intensely and selectively stained against a dark cytoplasmic background by several fluorescent cationic dyes. For example, the incorporation of Rhodamine 123 (RH123) into Mt depends on the membrane potential, accompanied by red shifts of absorption spectra and quenching of fluorescence intensity (Emaus et al., 1986). Though almost all the fluorescence dyes work in the ultraviolet and visible regions, our major goal is to develop the optically active contrast agents that can enhance and contrast the changes of energization of living tissues in near-infrared region. This is due to the fact that the light in the near-infrared region is more translucent to tissues than visible light. In this paper, we show the possible extrinsic optical probes, RH 123 as energy-dependent contrast reagent, though it works in visible region. Expanding to near-infrared region is also discussed.