Advantages and limits of the electrochemical method using Nafion and Ni-porphyrin-coated microelectrode to monitor NO release from cultured vascular cells

Electrochemical monitoring with a porphyrinic microsensor of in situ nitric oxide production from cultured cells offers numerous advantages but requir es cautious analysis, repeated calibration and accurate localisation of the electrode. It also had some limitations. We describe here some characteris tics of this method, the stability of the electrode response during experim ents and its application to nitric oxide production by constitutive and ind ucible nitric oxide synthases. Real-time measurements of NO concentration a llow the study of the kinetics of NO production. This is illustrated by the time-course of NO release from cultured human endothelial cells. How NO pr oduction by inducible nitric oxide synthase in cultured smooth muscle cells obtained from human internal mammary artery can he evaluated by Nafion- an d Ni-porphyrin-coated electrode is also described. The results thus obtaine d are compared to the cumulated NO2- production evaluated by the Griess met hod.