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Photoactivation and calcium sensitivity of the fluorescent NO indicator 4,5‐diaminofluorescein (DAF‐2): implications for cellular NO imaging
Author(s) -
Broillet Marie-Christine,
Randin Olivier,
Chatton Jean-Yves
Publication year - 2001
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(01)02206-2
Subject(s) - fluorescence , fluorometer , biophysics , divalent , chemistry , calcium , fluorescence microscope , analytical chemistry (journal) , chromatography , biology , optics , physics , organic chemistry
The fluorescent indicator of nitric oxide (NO), 4,5‐diaminofluorescein (DAF‐2), and its membrane‐permeable derivative (DAF‐2 diacetate) have been recently developed to perform real‐time biological imaging of NO. In this study, we show that DAF‐2 is strongly influenced by factors other than the concentration of NO itself. Using measurements with a fluorimeter as well as fluorescence microscopy, we found that the divalent cation concentration in the medium, as well as the incident light, strongly affects the ability of DAF‐2 to detect NO. Calcium, in particular, enhanced the signal detection of NO released by NO donors by up to 200 times. With multiple and longer exposures to light, no bleaching of the dye was observed but, instead, a potentiation of the fluorescence response could be measured. While these two properties will affect the use and interpretation of the hitherto acquired data with this fluorescent compound, they may also open up new possibilities for its application.