Visualization of nitric oxide production in the mouse main olfactory bulb by a cell-trappable copper(II) fluorescent probe.

We report the visualization of NO production using fluorescence in tissue slices of the mouse main olfactory bulb. This discovery was possible through the use of a novel, cell-trappable probe for intracellular nitric oxide detection based on a symmetric scaffold with two NO-reactive sites. Ester moieties installed onto the fluorescent probe are cleaved by intracellular esterases to yield the corresponding negatively charged, cell-impermeable acids. The trappable probe Cu(2)(FL2E) and the membrane-impermeable acid derivative Cu(2)(FL2A) respond rapidly and selectively to NO in buffers that simulate biological conditions, and application of Cu(2)(FL2E) leads to detection of endogenously produced NO in cell cultures and olfactory bulb brain slices.