New cardiac safety testing guidelines are being finalised, as part of the FDA’s Comprehensive in vitro Proarrhythmia Assay (CiPA) initiative, which aim to remove the over-reliance on screening against the hERG channel by expanding the panel to include hNav1.5, hCav1.2, hKv4.3/KChiP2.2, hKir2.1 and hKv7.1/KCNE1 human cardiac ion channels. In addition, the CiPA working groups have recently identified two additional in vitro assays required for in silico models to reliably predict proarrhythmia. The first is a ‘late’ sodium current assay, as inhibition of persistent inward current can affect repolarisation and mitigate proarrhythmia (e.g. ranolazine). The second assay quantifies the degree of drug trapping in the hERG channel using the Milnes voltage protocol, which can improve the prediction of proarrhythmic risk.
We developed a high-throughput, electrophysiological assay of TREK-1 function to identify novel modulators. The assay was optimized to identify both activators and inhibitors, providing comprehensive mechanistic data for high value, limited supply screening libraries, such as the venom fraction library used in this study (Targeted Venom Discovery Array, T-VDA, Venomtech, UK).
Scientifica’s PatchScope Pro is an integrated electrophysiology rig incorporating an inverted phase-contrast fluorescence microscope, motorised XY stage and PatchStar micromanipulators, suitable for patch-clamp recording.