Nitric oxide (NO) is an endogenous compound of the body involved in a variety of biological processes,1 including immunity-regulating functions, physiological control of blood pressure, and neurotransmission. Authentic NO in vivo has only a 0.1 s half-life.2 Nitrosothiols (RSNO), which are formed in vivo from the reaction of NO with protein or nonprotein thiols, can increase the effective tissue half-life of NO.3 RSNO is commonly referred to as a NO-donor and is found in various biological systems, such as in human plasma, airways, white blood cells, and rat cerebellum.4 Nitrosoglutathione (GSNO) has been shown to be one of the most aboundant RSNOs,4c,5,6 e.g., 0.3μM in bronchial lavage fluid and 0.7μM in brain, and to exhibit depressor action.7