The Mechanism(s) of Hypoxic Pulmonary Vasoconstriction: Potassium Channels, Redox O2Sensors, and Controversies

Abstract
Hypoxic pulmonary vasoconstriction matches perfusion to ventilation and optimizes systemic oxygenation. Alterations in Po2are sensed by a vascular redox O2sensor in the pulmonary artery smooth muscle cell, probably within the mitochondria. This creates a signal that modulates redox-sensitive K+channels, thereby controlling membrane potential, Ca2+entry, and tone.