Pulmonary arteries (PA) constrict in response to alveolar hypoxia, whereas systemic arteries
(SA) undergo dilation. These physiological responses reflect the need to improve gas
exchange in the lung, and to enhance the delivery of blood to hypoxic systemic tissues. An
important unresolved question relates to the underlying mechanism by which the vascular
cells detect a decrease in oxygen tension and translate that into a signal that triggers the
functional response. A growing body of work implicates the mitochondria, which appear to …