Figure 2

Single cell calcium signal and fluorescence intensity of the stable EP ₁ HEK293 cells. (I. & III.) Photomicrographs of stable EP₁ HEK293 cells showing baseline calcium signal (a, c, and e), and then the calcium signal produced following the addition of 1 nM PGE₁ (I.-b) or PGE₂ (III.-b), 100 pM PGE₁ (I.-d) or PGE₂ (III.-d), and wash buffer (I.-F and III.-f). The calcium signal is also shown for the untransfected HEK293 cells alone (I-g. and III.-g) and with 1 nM PGE₁ (I.-h) or PGE₂ (III.-h). (II. & IV.) Fluorescence intensity of the stable EP₁ HEK293 cells. The stable EP₁ HEK293 cells were grown in glass-bottom plates and incubated with Fluo8-AM dye, followed by the addition of 1 nM (black upright triangles) PGE₁ (II.) or PGE₂ (IV.), 100 pM (black squares) PGE₁ (II.) or PGE₂ (IV.), or wash buffer (II. and IV., black inverted triangles), and the calcium signals were evaluated using the Nikon Ti-S eclipse microscope and plotted as fluorescence intensity. Also shown is the fluorescence intensity of the pcDNA3.1 vector-transfected HEK293 control cells (II. and IV., black circles) and the untransfected HEK293 control cells in the presence of 1 nM (black diamonds) PGE₁ (II.) or PGE₂ (IV.).