Figure 2.

Effect of parathyroid hormone (PTH) on store-operated Ca²⁺ entry (SOCE) in human umbilical vein endothelial cells (HUVECs). (A,B) Representative traces (A) and summary data (B) showing thapsigargin (TG)-evoked SOCE in HUVECs after treatment with vehicle control, PTH (100 pM) or PTH plus BTP2 (an Orai nonspecific inhibitor) for 24 h. After depletion of the intracellular Ca²⁺ stores by treatment with 2 μM TG for 10 min in a Ca²⁺-free medium, SOCE was evoked by 2 mM Ca²⁺ application to the medium. Data are shown as the mean ± SEM; n = 7. **P < 0.01, ***P < 0.001 vs. Con or PTH. (C–E) Representative traces (C,D) and summary data (E) showing TG-evoked SOCE in HUVECs transfected with scrambled siRNA or Orai1 siRNA and treated with vehicle control or PTH (100 pM) for 24 h. (F,G) Representative images (F) and summary data (G) showing the effect of scrambled siRNA or Orai1 siRNA transfection on Orai1 expression in HUVECs. GAPDH was used as a loading control. (H) Summary data showing viability of HUVECs transfected with scrambled siRNA or Orai1 siRNA and treated with vehicle control or PTH (100 pM) for 24 h. Data are shown as the mean ± SEM; n = 4–5. *P < 0.05, **P < 0.01, ***P < 0.001 vs. Scrambled siRNA.