Figure 3.

Effects of Ex26, Ki16425, and BTP2 on the thapsigargin-evoked Ca²⁺ release and SOCE. SOCE responses were analysed with Fura-2. Cells were kept in a nominally Ca²⁺-free medium. ER Ca²⁺ stores were depleted with thapsigargin (Tg, 200 nM) before re-introducing external Ca²⁺. The resulting increase in intracellular Ca²⁺ is due to Ca²⁺ entering via the plasma membrane. Panel A shows somatic Ca²⁺ responses (expressed as Δ ratio F340/F380) as a function of time, and generated by the sequential addition of Tg (200 nM, horizontal gray bar) followed by the readmission of 2 mM external Ca²⁺ (horizontal black bar). Four conditions are shown: without antagonists of LPA and S1P receptors (Control, open circles, n = 7), with 1 µM Ex26 (gray triangles, n = 5), with 10 µM Ki16425 (filled squares, n = 5), and with 1 µM BTP2 (symbols, n = 5). When tested, Ex26 (or Ki16425) and BTP2 were added 4–7 and 11–12 min, respectively, before time 0 and were also present during the recordings. One time point out of 3 is shown. Panel B shows the thapsigargin-evoked Ca²⁺ release and SOCE measured as area under the curve (AUC). Mean ± SEM.