Single cell determination of nitric oxide release using capillary electrophoresis with laser-induced fluorescence detection.

Measurements of nitric oxide (NO) release at single cell level are fundamental to understand the diverse physiological functions of this remarkable molecule. To achieve this purpose, capillary electrophoresis with laser-induced fluorescence detection (CE-LIF) was originally described for the sensitive determination of NO release in individual neuron and mammalian cell after 8-(3,4-diaminophenyl)-2,6-bis(2-carboxyethyl)-4,4-difluoro-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene (DAMBO-P(H)) was chosen as the fluorescent probe. Various parameters affecting NO trapping in vivo and CE separation were systematically studied. Under the optimal conditions, complete and fast separation of the resulted targeted high-fluorescent triazole (DAMBO-P(H)-T) was achieved in about 3 min (2.89 min), and the relative standard deviations (RSDs) values of migration time and peak area were less than 5% and 9% for intra-day and inter-day assays, respectively. The detection limit was 42 amol (at a signal-to-noise ratio of 3). The feasibility of application of the developed method was validated by successfully applied to the measurements of NO release from four single cell study models. This original application of this method in diverse samples represents a powerful tool to study the kinetics of NO release by neuronal cells during neurotransmission, as well as for the understanding of the pathobiological and therapeutic basis of this molecule for cardiovascular diseases and under oxidative stress.