Hypoxia-Dependent TRP Channel Function in Pulmonary Arterial Smooth Muscle Cells

Hypoxic pulmonary vasoconstriction (HPV) is an essential physiological mechanism of the lung which matches perfusion to ventilation to optimize gas exchange. Pulmonary arterial smooth muscle cells (PASMC) are the effector and possibly also the sensor cells of HPV. Contraction of these cells under hypoxia is induced by an increase in intracellular Ca²⁺ concentration ([Ca²⁺ ]_i ). To investigate details of the hypoxia-induced increase in [Ca²⁺ ]_i , we use a live cell imaging procedure with fura-2 in isolated wild-type (WT) and gene-deficient mouse PASMC. We also describe here the manganese-quenching method to determine the role of nonselective cation influx through transient receptor potential (TRP) channels in response to hypoxia.