FIG. 1.
Possible nitric oxide synthase (NOS)-dependent pathways leading to the in vitro formation of nitroxyl or nitrosyl hydride (HNO). In addition to the direct oxidation of NG-hydroxy-L-arginine (NOHA) when NOS is uncoupled and to the possibility of generating HNO via tetrahydrobioterpin (BH4)-free NOS, the lower part of the diagram highlights the possibility of forming HNO from the decomposition of S-nitrosothiols. (To see this illustration in color the reader is referred to the web version of this article at www.liebertonline.com/ars).