Redox thiol status plays a central role in the mobilization and metabolism of nitric oxide in human red blood cells |
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Authors: | José Pedro Lopes de Almeida Filomena Almeida Carvalho Teresa Santos-Freitas |
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Institution: | a Santa Maria Hospital, University of Lisbon Medical School, Av Prof. Egas Moniz, 1649-028 Lisbon, Portugal b Institute of Biochemistry, Institute of Molecular Medicine, University of Lisbon Medical School, Av Prof. Egas Moniz, 1649-028 Lisbon, Portugal |
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Abstract: | We assessed the redox thiol status influence on nitric oxide (NO) metabolism and efflux in erythrocytes stimulated with acetylcholinesterase substrate (acetylcholine, ACh) and inhibitor (velnacrine maleate, VM). Erythrocyte suspensions from healthy donors were incubated with increasing concentrations of dithiothreitol (1-50 μM), in the presence and absence of acetylcholine/velnacrine (10 μM). Levels of NO, nitrite/nitrate, S-nitrosohemoglobin, peroxynitrite and S-nitrosoglutathione were determined by spectrofluorimetric and spectrophotometric methods.Dithiothreitol significantly mobilized NO toward nitrite/nitrate and S-nitrosoglutathione, and decreased the amount of NO efflux. Both ACh/VM induce changes on the levels of erythrocyte nitrite/nitrate dependent on the DTT concentration. Higher levels of peroxynitrite and S-nitrosoglutathione were seen with velnacrine in presence of DTT 1 and 50 μM.We concluded that dithiothreitol-induced activation of erythrocyte thiol status decreases NO efflux and allows greater intracellular NO mobilization onto different derivative molecules, both in the absence and presence of acetylcholinesterase substrate and inhibitor. |
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Keywords: | Acetylcholinesterase Erythrocyte Nitric oxide Redox thiol status S-nitrosothiols |
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