Non-borinate esters are either uneffective or inhibitors of SOCE. Dose-response curve of [Ca2+]i to 2-APB analogues were obtained as in figure 2C. A. DMBA, DPTHF and DP3A are inhibitors of SOCE. B. Mn2+ quenching of indo-1 in BL41 cells stimulated by two concentrations of DMBA or 2-APB. Same as in figure 2B, except that 1 and 20 μM DPBA or 2-APB were used. C and D. Cytosolic calcium concentration measurement of BL41 cells in 2-APB/DMBA competition experiments. Cells were treated 400s with TG 1 μM to allow Ca2+ release from ER and opening of SOC channels. Then 1 mM CaCl2 was added, allowing Ca2+ entry through SOC channels. 2-APB 10 μM ("2-APB", C), DMBA 10 μM ("DMBA", D) or 2-APB 10 μM + DMBA 10 μM ("2-APB + DMBA", C and D) were applied 30 s prior to CaCl2. In competition experiments, DMBA 10 μM was applied 100 s after CaCl2 adding on cells treated by 2-APB ("2-APB then DMBA", C) or 2-APB 10 μM was applied 100 s after CaCl2 adding on cells treated by DMBA ("DMBA then 2-APB", D). Error bars were omitted for clarity (maximum ~ ± 50 nM). E. Diphenhydramine and phenytoine are weak inhibitors of SOCE, although PBA is inefficient. Same experiment as done in figure 3A. F. Mn2+ quenching of indo-1 in BL41 cells by low and high concentrations of DPTHF and DP3A, compared to 2-APB. Same protocol was used as in figure 2B. The two analogues were used at 10 μM and 50 μM. G and H. Values of Indo-1 quenching in presence of the borinate esters were normalised to values obtained in the lonely presence of Mn2+ ions, respectively from B and F.