Oxygen tension, H₂S, and NO bioavailability: is there an interaction?

Molecular oxygen (O₂) is an essential component for survival and development. Variation in O₂ levels leads to changes in molecular signaling and ultimately affects the physiological functions of many organisms. Nitric oxide (NO) and hydrogen sulfide (H₂S) are two gaseous cellular signaling molecules that play key roles in several physiological functions involved in maintaining vascular homeostasis including vasodilation, anti-inflammation, and vascular growth. Apart from the aforementioned functions, NO and H₂S are believed to mediate hypoxic responses and serve as O₂ chemosensors in biological systems. In this literature review, we briefly discuss NO and H₂S and their roles during hypoxia.