Stopped-Flow Fluorometric Ion Flux Assay for Ligand-Gated Ion Channel Studies Academic Article uri icon


MeSH Major

  • Cyclic AMP
  • Potassium Channels
  • Rhizobium


  • Quantitative investigations into functional properties of purified ion channel proteins using standard electrophysiological methods are challenging, in particular for the determination of average ion channel behavior following rapid changes in experimental conditions (e.g., ligand concentration). Here, we describe a method for determining the functional activity of liposome-reconstituted K+ channels using a stopped-flow fluorometric ion flux assay. Channel activity is quantified by measuring the rate of fluorescence decrease of a liposome-encapsulated fluorophore, specifically quenched by thallium ions entering the liposomes via open channels. This method is well suited for studying the lipid bilayer dependence of channel activity, the activation and desensitization kinetics of ligand-dependent K+ channels, and channel modulation by channel agonists, blockers, or other antagonists.

publication date

  • January 2018



  • Academic Article



  • eng

Digital Object Identifier (DOI)

  • 10.1007/978-1-4939-7362-0_17

PubMed ID

  • 29058195

Additional Document Info

start page

  • 223

end page

  • 235


  • 1684