Intracellular Calcium Measurements Using Fluo-3 Fluorescence

This application note reports on a highly sensitive method for measuring changes of the intracellular calcium concentration (Cai) in a renal epithelial cell line (HEK 293T) and a pituitary tumor cell line (GH4/C1) using the visible light-excitable calcium sensitive dye fluo-3 (Molecular Probes, Inc.). The basal intra-cellular fluo-3 fluorescence and the effects of substances known to elevate Cai – either via calcium in-flux or liberation from intracellular stores – were investigated. Among the substances tested were the calcium ionophore antibiotic ionomycin, ATP and extracellularly applied ethanol.