<p><b>OBJECTIVE</b>To investigate the effect of hypoxia on the human pulmonary artery smooth muscle cells two pore domain potassium channels TASK-1 and the regulation of non-receptor tyrosine kinase c-Src in this process.</p><p><b>METHODS</b>The cultured human pulmonary artery smooth muscle cells (hPASMCs) were divided into: normal group, hypoxia 30 minute group, hypoxia 6 hours group and hypoxia 48 hour group, and hypoxia 48 hour + PP2 group, hypoxia 48 hour + PP3 group, hypoxia 48 hour + bpV group. Flow cytometry was used to analyze the cell cycle, RT-PCR and Western blot technique were carried out to detect the expression changes of TASK-1 mRNA and protein in different groups.</p><p><b>RESULTS</b>(1) Cell Cycle Show: Compared with normal control group, with prolonged hypoxia, the percentages of hPASMCs in S phases of cell cycle were increased. While compared with hypoxia 48 hour group, the percentages of hypoxia 48 hour + PP2 group hPASMCs in S phases of cell cycle were decreased. The expression of TASK-1 mRNA on hPASMCs in acute hypoxia 6 hour group was increased, while the expression of TASK-1 protein on hPASMCs in the acute and chronic hypoxia group was decreased, and the expression of TASK-1 mRNA on hPASMCs in the chronic hypoxia group was decreased; After pre-incubation of a potent and selective inhibitor of the Src family of protein tyrosine kinases PP2, the expression of TASK-1 mRNA and protein in hypoxia 48 hour group was increased, however after pre-incubation of the inhibitor of the Src family of protein tyrosine phosphatase bpV, the expression of TASK-1 protein in hypoxia 48 hour group was decreased.</p><p><b>CONCLUSION</b>Hypoxia promotes human pulmonary artery smooth muscle cell proliferation, and non-receptor tyrosine kinase c-Src may participate in the expression of two pore domain potassium channels TASK-1 regulated by hypoxia. Therefore, we hypothesized that TASK-1 channels and c-Src participatein the acute and chronic hypoxic human pulmonary vasoconstriction.</p>