Optimization of a High-Throughput Assay for Calcium Channel Modulators on IonWorks Barracuda

Assay Drug Dev Technol. 2016 Mar;14(2):75-83. doi: 10.1089/adt.2015.678. Epub 2015 Dec 30.

Abstract

Voltage-gated calcium channels represent important drug targets. The implementation of higher throughput electrophysiology assays is necessary to characterize the interaction of test compounds with several conformational states of the channel, but has presented significant challenges. We report on the development of a high-throughput, automated electrophysiology assay for Cav2.2 on the IonWorks Barracuda™ platform. The assay provides an assessment of the potency of the test compound on the resting/closed and inactivated states of the channel in the same assay run. Inclusion of the heavy metal chelator 2,3-bis(sulfanyl)propane-1-sulfonate in the assay solutions improved the data quality by reversing a loss of current seen in wells directly above the ground electrodes. We hypothesize that the loss of current is caused by block of Cav2.2 currents by silver ions originating from the electrodes.

MeSH terms

  • Animals
  • Calcium Channel Blockers / pharmacology*
  • Calcium Channels, N-Type / metabolism*
  • Cells, Cultured
  • Chelating Agents / pharmacology*
  • Dose-Response Relationship, Drug
  • Electrodes
  • HEK293 Cells
  • High-Throughput Screening Assays*
  • Humans
  • Patch-Clamp Techniques
  • Rats
  • Silver / pharmacology*
  • Structure-Activity Relationship

Substances

  • Cacna1b protein, rat
  • Calcium Channel Blockers
  • Calcium Channels, N-Type
  • Chelating Agents
  • Silver