Editorial focus: Oxygen sensors and mediators of the contractile responses of smooth muscle to hypoxia. Focus on: 'hydrogen sulfide mediates hypoxic vasoconstriction through a production of mitochondrial ROS in trout gills'

摘要

smooth muscle cells (smcs) in vascular and other tissues reversibly change their tone in response to acute variations in oxygen tension, and this results in important physiological and pathophysiological responses of the organ or system. The best studied example includes the changes in blood vessel diameter in response to decreases in oxygen tension (hypoxia). Thus, in response to tissue hypoxia, systemic peripheral arteries normally dilate, thereby increasing oxygen delivery into the tissue. Conversely, in the lung, hypoxia constricts the pulmonary arteries-a response called hypoxic pulmonary vasoconstric-tion (HPV), which can have either beneficial effects, by reducing and diverting blood flow from poor ventilated regions in the lung and thus optimizing ventilation-perfusion matching and gas exchange, or detrimental effects by increasing pulmonary vascular resistance, resulting in pulmonary hypertension at high altitude or during lung disease (3). In addition, the SMCs in other systems also respond to changes in oxygen tension. For example in the lung, the airways relax in response to hypoxia (7), which also may have a role in ventilation-perfusion matching by facilitating ventilation of hypoxic alveoli.