Electrochemical and UV-Vis spectroscopic measurements of nitric oxide in fibroblasts and astrocytes

Two complementary analytical methods were applied to measure nitric oxide p roduction in two cell cultures of fibroblasts and astrocytes: W-vis spectro scopic assay of nitrites based on Griess reaction and direct, electrochemic al determination of nitric oxide with use of a 5 mm diameter disk porphyrin ic sensor. The nitrite measurement was used in order to get total quantitat ive information on NO production in a specified time. Application of an ele ctrochemical sensor allowed observation of the dynamics and stabilization o f nitric oxide production in real time, in the vicinity of a culture of sti mulated cells. In experiments, cell suspension was placed just above the se nsor surface or cells were grown directly on the modified electrode. Curren t curves were recorded after base current stabilization and injection of L- arginine the last remaining cosubstrate in the system. Collected data enabl ed one to estimate the local concentration of nitric oxide produced in the culture of fibroblasts to be 70 nM.