CHEMBL5733366

Sodium Influx Assay (In Vitro Assay): This sodium influx assay employs the use of the cell permeable, sodium sensitive dye ANG2 to quantify sodium ion influx through sodium channels which are maintained in an open state by use of sodium channel modulators. This high throughput sodium influx assay allows for rapid profiling and characterization of sodium channel blockers.In general, Trex HEK293 cells were stably transfected with an inducible expression vector containing the full-length cDNA coding for the desired human sodium channel α-subunit and with an expression vector containing full length cDNA coding for the β1-subunit. Sodium channel expressing cell lines were induced with tetracycline (1 μg/mL) and plated on 384-well PDL-coated plates at a density of 25K-30K cells/well in culture media (DMEM, containing 10% FBS and 1% L-glutamine). After overnight incubation (37° C., 5% CO2), culture media was removed and cells were loaded with 5 uM ANG2 dye for 1-1.5 h in Buffer 1 (155 mM NMDG, 5 mM KCl, 2 mM CaCl2, 1 mM MgCl2, 10 mM HEPES, 10 mM glucose, adjusted with Tris to pH 7.4). Access dye was removed and cells were incubated with test compounds for 1 hr in buffer 1 containing sodium channel modulator(s) at room temperature. Hamamatsu FDSS ρCell was used to perform a 1:1 addition of Na/K challenge buffer (140 mM NaCl, 20 mM HEPES, 1 mM CaCl2, 15 mM KCl, 1 mM MgCl2, 10 mM glucose, adjusted with Tris to pH 7.4) and simultaneously read plates at excitation wavelength of 530 nm and emission wavelength set at 558 nm. Percent inhibition of sodium ion influx was calculated for each test compound at each test concentration to determine the IC50 values.