Rapid microspectrofluorimetry for biochemical and metabolic studies in single living cells

A rapid multichannel microspectrofluorometer (e.g., to NAD(P)H, fluorescent probes) can be operated on a topographic mode for the evaluation of intracellular metabolic topography or on a spectral mode for the individual or simultaneous intracellular spectral analysis of various fluorochromes. The fluorescence emission spectra of the living cells, as well as difference spectra (spectra after intracellular microelectrophoretic addition of substrate minus before)_are analyzed under various conditions, and provide a direct proof that the fluorescence observed is that of NAD(P)H. The spectral changes which accompany treatment with substrate (e.g., glucose-6-P) can be further followed in cells incubated with other probes (e.g., acridine orange). Repeated and quite reversible transients of NAD(P) reduction—reoxidation may be observed in cells having absorbed acridine orange following repetitive additions of substrate. The spectral response to substrate is also comparatively studied in cells grown in presence of agents affecting the cell cycle (e.g., dibutyryl cyclic AMP, bleomycin).