Figure 1.

Effect of loperamide (L; 30 μM) on levels of intracellular calcium before and after release of intracellular calcium and subsequent activation of SOC channels in HL-60 cells. Elevation of intracellular calcium levels before the addition of loperamide was by (A) 10 μM ATP, (B) 15 nM thapsigargin (T), (C) 10 μM ionomycin (I), and (D) a combination of 10 μM ATP, 15 nM thapsigargin, and 1 μM ionomycin. Elevation of intracellular calcium levels after the addition of loperamide was by (E) 10 μM ATP, (F) 15 nM thapsigargin (T), and (G) 10 μM ionomycin (I). Cells were loaded with fluo3-AM.