Role of endothelial nitric oxide in pulmonary and systemic arteries during hypoxia

A complex equilibrium is established between NO, sGC and CcO in vessels in function of the concentration of O2: as O2 falls, NO inhibition of mitochondrial O2 consumption increases and activation of sGC decreases, thus promoting a rapid increase in tone in both pulmonary and systemic vessels, which is followed by the triggering of NO-independent vasodilator/vasoconstrictor mechanisms.