Simultaneous Recordings of Ligand-Gated Ion Channels using a 384 Planar Patch Clamp Substrate

Abstract

We have developed an apparatus that allows the simultaneous measurement of ligand-gated ion channels (LGICs) at 384 separate recording sites in parallel prior to, during and after ligand addition. Since the development of planar patch clamp recording techniques in 2002 the number of parallel recordings that could be done on LGICs has been limited to 48. Our apparatus measures cell membrane currents using the perforated patch clamp techniques on a polyimide substrate. Currents are measured using a single hole at each recording site or an array of 64 holes at each site (Population Patch Clamp or PPC, Finkel et al. 2006). PPC averages the membrane currents in the 64 cells at each recording site by measuring the ensemble current through all 64 cells using a single pair of electrodes. PPC increases the success rates by mitigating biological variability caused largely by cells not expressing the channel of interest. We present here the consistent ability to measure cell membrane currents simultaneously from all 384 sites. Data presented include LGIC recordings of GABA chloride channels, acid sensing ion channels (ASIC), and nicotinic acetylcholine (α1 nACh) receptors. In addition to the LGIC data presented we also present recordings of voltage-gated ion channels (VGICs) including NaV, KV and hERG channels. Pharmacological blockade of ion channel activity is also presented to validate the use of this apparatus for screening ion channel targets in a drug discovery setting.Ref: Finkel, A. et al. (2006). J Biomol Screen11(5): 488-96.