NOS1 and Stroke: In stroke pathology, the levels of GSNO and the consequent S-nitrosylated proteins are believed to decrease due to four major reasons: (a) decreased oxygen supply under ischemic/hypoxic condition reduces GSNO biosynthesis; (b) excessive superoxide formed during reperfusion instantaneously reacts with nitric oxide synthase (NOS)-derived NO, forming peroxynitrite and thus reducing NO bioavailability for GSNO biosynthesis; (c) biosynthesis of GSNO is decreased as a result of reduced levels of glutathione (redox imbalance) and NO (due to its reaction with superoxide) under IR conditions.