Studying Nicotinic Acetylcholine Receptors Using the IonFlux™ Microfluidic-Based Automated Patch-Clamp System with Continuous Perfusion and Fast Solution Exchange.

Abstract

Automated patch‐clamp (APC) systems have become indispensable tools of drug‐discovery programs by allowing high‐throughput electrophysiology‐based screening of ion channel compounds. The recent development and introduction of microfluidics‐based APC systems have made it possible to study the interactions of ligand‐gated ion channels with pharmacological reagents, such as agonists, antagonists, or positive allosteric modulators (PAMs), with reliable pharmacological results comparable to those of the gold‐standard manual patch‐clamp technique while maintaining high‐throughput capacity. Many ligand‐gated ion channels exhibit rapid desensitization upon repetitive introduction of ligands; this loss of channel activity in the absence of pharmacological interaction poses a challenge for developing accurate, precise, and robust assays with high success rate, low run‐down, and reliable pharmacological results. Here we present procedures to study nicotinic acetylcholine receptors (nAChRs) with the IonFlux™, an automated patch‐clamp system with continuous flow and precise fluidic exchange; these procedures can also be generalized to the study of other ligand‐gated ion channels. We present protocols to study agonist, antagonist, and PAM activities on nAChRs, particularly the rapidly desensitizing nAChR α7 receptors. The data demonstrate that the IonFlux™ system is a fast, robust, and reliable platform for the study of nAChRs and other ligand‐gated ion channels, generating data that closely mimic those from manual patch‐clamp conditions. © 2020 by John Wiley & Sons, Inc.