A high-throughput HERG potassium channel function assay: An old assay with a new look

In this paper, we describe an assay using radioactive rubidium (Rb-86) efflux to screen functional human ether-a go-go-related gene (HERD) K+ channels in a high-throughput screening (HTS) format. This assay offers an alternative way to examine functional interactions between chemical compounds and HERG K+ channels. Follow-up experiments and discussions were carried out to address a variety of factors that affect potency evaluation within the Rb efflux assay. Factors that can affect the assay results, such as assay time, efflux rate, and compound blocking kinetics, are discussed in detail. Our results provide some explanations for the variances of the assay results and offer some guidelines for using the Rb efflux assay to evaluate compound interactions with HERG K+ channels in the pharmaceutical industry.