Hypoxia selectively inhibits KCNA5 channels in pulmonary artery smooth muscle cells.

Acute hypoxia induces pulmonary vasoconstriction and chronic hypoxia causes pulmonary vascular remodeling characterized by significant vascular medial hypertrophy. Electromechanical and pharmacomechanical mechanisms are involved in regulating pulmonary vasomotor tone, while changes in cytosolic Ca2+ concentration ([Ca2+](cyt)) are an important signal in regulating contraction and proliferation of pulmonary artery smooth muscle cells (PASMC). Hypoxia-induced increases in [Ca2+](cyt) are, in part, mediated by selective inhibition of voltage-gated K+ (Kv) channels in PASMC.