Aim To evaluate the time-course curve of expression of TRPC1 and vascular tone of pulmonary arteries(PAs)mediated by SOCE in chronic hypoxia pulmonary hyperte-nsion rats.Methods Both tension of PA rings and expression of TRPC1 were tested in CH exposure (1 0.0 % ±0.5 %partialpressure ofoxygen ) induced pulmonary hypertensive (PH)rats,and the time-course curve(detected respectively in CH 1 ,3,5, 7,1 4,21 d)was traced.Results ①CH could up-regulate the mean right ventricular pressure(mRVSP) ,which was increased significantly on 1 d,and reached the maximum on 7d;right ventricular weight index (RV-MI)began increase on 3d,and kept rising;②semi-quantitative reverse transcription polyme-rase chain reaction (RT-PCR)was performed to detect the expression of TRPC1 in PAs.The expression of TRPC1 increased significantly on 1 d,and reached the maxi-mum on 3d;③CH could up-regulate the vascular tone of PAs mediated by SOCE,which was increased signif-icantly on 3d,and reached the maximum on 7d.Con-clusions TRPC1 /SOCE increases significantly in the early days of CH,and the time-course curve of the two has correlation,which reflects the important role of the upregulation of TRPC1 /SOCE in the process of chronic hypoxia pulmonary hypertension.