The vasorelaxant effect and its mechanisms of sodium bisulfite as a sulfur dioxide donor

► Sodium bisulfite relaxed rat aortic rings in a concentration-dependent manner. ► Sodium sulfite at low concentrations caused vasoconstriction. ► Vasorelaxation of bisulfite at low concentrations related to cGMP pathway. ► Vasorelaxation of bisulfite at high concentrations related to K+ and Ca2+ channels. ► Sodium bisulfite was used as a SO2 donor for the study of SO2 biology.