Brief communicationNitric oxide stimulates the erythrocyte for ascorbate recycling

S-Nitrosothiols act as carrier and reservoir of nitric oxide (NO), and release NO under stimulation of ascorbate (Asc). Erythrocyte can regenerate Asc from its oxidised products, thus saving this powerful antioxidant. In this paper the effect of donors of NO, superoxide, and peroxynitrite (SpNONOate, KO2, and SIN-1, respectively) on the erythrocyte production of Asc was investigated. We report here that NO stimulated, while superoxide and peroxynitrite decreased, the Asc recycling. The NO-stimulating effect on the erythrocyte production of Asc was confirmed by using GSNO, a natural occurring S-nitrosothiol, as NO donor. These data highlight a new property of NO, that is the stimulation of erythrocytes for their Asc recycling. Such a property might contribute to regenerate Asc from its oxidised forms, thus preventing its depletion in the circulation. Temperature and pH significantly affected, both in absence and presence of NO, the recycling of Asc by erythrocytes. We propose that a positive feedback, involving the reciprocal stimulation between Asc and S-nitrosothiols, might enhance productions of Asc by erythrocytes and NO release by circulating S-nitrosothiols.