FIGURE 1.
Effect of PMA and serum on [Ca2+]i and AA release in IMLF+/+. A, [3H]AA-labeled IMLF+/+ were stimulated with 10% serum (right) or 100 nm PMA (left) and [3H]AA release was determined at given times and compared with unstimulated (US) cells. [3H]AA released into the medium was measured and expressed as a percentage of the total cellular radioactivity in each well. The results are the average of three experiments ± S.E. for PMA (left) and two experiments ± S.D. for serum (right). B, live cell calcium imaging of IMLF+/+ loaded with the fluorescent calcium indicator FuraRed-AM was measured after the addition (arrows) of serum, PMA, or vehicle (DMSO). Calcium changes are shown in individual cells stimulated with 10% serum without (panel 1) or with (panel 2) a 15-min preincubation in EGTA. Panel 3 shows calcium oscillations in cells stimulated with 100 nm PMA for 30 min. Panel 4 illustrates calcium changes in cells stimulated with PMA with an EGTA preincubation. Panel 5 shows control cells (incubated without EGTA) using DMSO vehicle in place of PMA. Calcium changes were determined by correcting for background fluorescence values from each cell and calculated as a ratio of bound to unbound calcium fluorescence intensities (F403/F470). Data are presented relative to time 0 (RT/R0), and starting (RT/R0) for each cell is set at 1. Each line represents data from an individual cell. Graphs are representative of a minimum of three independent experiments.