Cyclopiazonic Acid Promotes Store-Operated Ca2+ Entry in HEK293 Cells

HEK293 cells were incubated with cytosolic Ca2+ sensitive dye, Fura-2AM for 40 min, washed and kept in the normal tyrode buffer for 20 min. Fura2-loaded cells were excited alternately at 340 and 380 nm and fluorescence at 510 nm was expressed as 340/380 ratio. 25 μM CPA depletes intracellular Ca2+ stores and promotes store-operated Ca2+ entry into the cells upon addition of 1 mM extracellular Ca2+.