Hypoxic pulmonary hypertension is characterized by increased vascular tone, altered vasoreactivity and profound vascular remodeling, which are associated with alterations in Ca2+ homeostasis in pulmonary arterial smooth muscle cells.We have previously shown that transient receptor potential channel 1 and 6 are upregulated in pulmonary arteries of chronic hypoxic rats, but it is unclear whether these channels are essential for the development of pulmonary hypertension.