Because ion channel activity is sensitive to interference, and chemical interference with a particular ion channel is highly unpredictable, the FLIPR Membrane Potential Assay Kits have two formulations. Both formulations combine the advantages of our proprietary membrane potential indicator dye with our patented quench technology. One formulation uses a blue quencher and the other formulation uses a red quencher. We recommend that both versions be evaluated for each individual target/cell line to determine which formulation will provide optimal performance.
Modulation of a Nav1.5 channel in CHL-hH1 cells by tetrodotoxin. In this assay, 30 mM veratridine is used to hold the sodium channel in its open state. Modulation occurs as tetrodotoxin concentration increases. A rapid influx of Na+ into the cell occurs, subsequently depolarizing the membrane, and leading to an increase in fluorescence. In this assay, the Membrane Potential Red Kit showed the larger signal window and larger Z factor.