Hypoxic pulmonary vasoconstriction: Role of ion channels

Acute hypoxia induces pulmonary vasoconstriction and chronic hypoxia causes structural changes of the pulmonary vasculature including arterial medial hypertrophy. Electro- and pharmacomechanical mechanisms are involved in regulating pulmonary vasomotor tone, whereas intracellular Ca²⁺ serves as an important signal in regulating contraction and proliferation of pulmonary artery smooth muscle cells. Herein, we provide a basic overview of the cellular mechanisms involved in the development of hypoxic pulmonary vasoconstriction. Our discussion focuses on the roles of ion channels permeable to K⁺ and Ca²⁺, membrane potential, and cytoplasmic Ca²⁺ in the development of acute hypoxic pulmonary vasoconstriction and chronic hypoxia-mediated pulmonary vascular remodeling.