Aim To evaluate the effects of notoginsen-oside R1 on store-operated calcium entry ( SOCE ) in pulmonary arterial smooth muscle cells ( PASMCs ) of chronic hypoxia ( CH)-and monocrotaline ( MCT)-in-duced pulmonary hypertension ( PH) rats. Methods Mn2+ quenching of Fura-2 and measurement of intra-cellular free calcium concentration ( [ Ca2+] i ) using fluo-3 were examined in PASMCs of CH-exposed and MCT-treated rats. Results ①CH-exposed and MCT-treated rats exhibited profound PH when examined 3 weeks after hypoxia exposure or MCT injection, respec-tively. ②In the presence of 3 μmol·L-1 nifedipine, 10 μmol · L-1 notoginsenoside R1 significantly re-duced cyclopiazonic acid ( CPA )-induced the percent reduction in Fura-2 fluorescence measured 500 sec af-ter application of Mn2+, the maximal rate of Mn2+quenching, the amplitude of the Ca2+ influx transient and the resting [ Ca2+] i in PASMCs of CH-exposed and MCT-treated rats. Conclusion Notoginsenoside R1 inhibits SOCE and reduces resting [ Ca2+] i in PASMCs of CH-and MCT-induced PH rats.

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.