A cell-permeable, photo-stable nitric oxide (NO) fluorescent indicator with a detection limit of ~10 nM. Intracellularly releases DAR-4M by the action of esterases. Reacts with NO, in the presence of oxygen, resulting in a triazolo-rhodamine analog (DAR-4M T) that exhibits about 840-fold greater fluorescence quantum efficiency. The fluorescence intensity is not dependent on pH.
