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Although automated patch clamp (APC) devices have been around for many years and have become an integral part of many aspects of drug discovery, high throughput instruments with gigaohm seal data quality are relatively new. Experiments where a large number of compounds are screened against ion channels are ideally suited to high throughput APC, particularly when the amount of compound available is low. Here we evaluate different APC approaches using a variety of ion channels and screening settings. We have performed a screen of 1920 compounds on GluN1/GluN2A NMDA receptors for negative allosteric modulation using both the SyncroPatch 384 and FLIPR. Additionally, we tested the effect of 36 arthropod venoms on Na V 1.9 using a single 384-well plate on the SyncroPatch 384. As an example for mutant screening, a range of acid-sensing ion channel variants were tested and the success rate increased through fluorescence-activated cell sorting (FACS) prior to APC experiments. Gigaohm seal data quality makes the 384-format accessible to recording of primary and stem cell-derived cells on the SyncroPatch 384. We show recordings in voltage and current clamp modes of stem cell-derived cardiomyocytes. In addition, the option of intracellular solution exchange enabled investigations into the effects of intracellular Ca 2+ and cAMP on TRPC5 and HCN2 currents, respectively. Together, these data highlight the broad applicability and versatility of APC platforms and also outlines some limitations of the approach. KEY POINTS: High throughput automated patch clamp (APC) can be used for a variety of applications involving ion channels. Lower false positive rates were achieved using automated patch clamp versus a fluorometric imaging plate reader (FLIPR) in a high throughput compound screen against NMDA receptors.  Genetic variants and mutations can be screened on a single 384-well plate to reduce variability of experimental parameters. Intracellular solution can be perfused to investigate effects of ions and second messenger systems without the need for excised patches. Primary cells and stem cell-derived cells can be used on high throughput APC with reasonable success rates for cell capture, voltage clamp measurements and action potential recordings in current clamp mode., (© 2021 The Authors. The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.)

Introduction: For reliable identification of cardiac safety risk, compounds should be screened for activity on cardiac ion channels in addition to hERG, including Na V 1.5 and Ca V 1.2. We identified different parameters that might affect IC 50 s of compounds on Na V 1.5 peak and late currents recorded using automated patch clamp (APC) and suggest outlines for best practices., Methods: APC instruments SyncroPatch 384 and Patchliner were used to record Na V 1.5 peak and late current. Up to 24 CiPA compounds were used to investigate effects of voltage protocol, holding potential (-80 mV or - 95 mV) and temperature (23 ± 1 °C or 36 ± 1 °C) on IC 50 values on hNa V 1.5 overexpressed in HEK or CHO cells either as frozen cells or running cultures., Results: The IC 50 s of 18 compounds on the Na V 1.5 peak current recorded on the SyncroPatch 384 using the CiPA step-ramp protocol correlated well with the literature. The use of frozen or cultured cells did not affect IC 50 s but voltage protocol and holding potential did cause differences in IC 50 values. Temperature can affect V half of inactivation and also compound potency. A compound incubation time of 5-6 min was sufficient for most compounds, however slow acting compounds such as terfenadine required longer to reach maximum effect., Discussion: We conclude that holding potential, voltage protocol and temperature can affect IC 50 values and recommend the use of the CiPA step-ramp protocol at physiological temperature to record Na V 1.5 peak and late currents for cardiac safety. Further recommendations include: a minimum compound incubation time of 5 min, a replicate number of 4 and the use of positive and negative controls for reliable IC 50 s., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Introduction: Automated patch clamp (APC) devices have become commonplace in many industrial and academic labs. Their ease-of-use and flexibility have ensured that users can perform routine screening experiments and complex kinetic experiments on the same device without the need for months of training and experience. APC devices are being developed to increase throughput and flexibility. Areas covered: Experimental options such as temperature control, internal solution exchange and current clamp have been available on some APC devices for some time, and are being introduced on other devices. A comprehensive review of the literature pertaining to these features for the Patchliner, QPatch and Qube and data for these features for the SyncroPatch 384/768PE, is given. In addition, novel features such as dynamic clamp on the Patchliner and light stimulation of action potentials using channelrhodosin-2 is discussed. Expert opinion: APC devices will continue to play an important role in drug discovery. The instruments will be continually developed to meet the needs of HTS laboratories and for basic research. The use of stem cells and recordings in current clamp mode will increase, as will the development of complex add-ons such as dynamic clamp and optical stimulation on high throughput devices.