• Patchliner

    Most versatile automated patch clamp system on the market
  • Patchliner

    In-house production and QC of consumables
  • Patchliner

    More than 10 years experience in assay design and support
  • Dynamite8

    Automated Dynamic Clamp
  • Patchliner

    All features & benefits of manual patch clamp

2022 - Low potency inhibition of NaV1.7 by externally applied QX-314 via a depolarizing shift in the voltage-dependence of activation

icon pl  Patchliner publication in European Journal of Pharmacology (2022)

Authors:
Klasfauseweh T., Israel M.R., Ragnarsson L., Cox J.J., Durek T., Carter D.A., Leffler A., Vetter I., Deuis J.R.

Journal:
European Journal of Pharmacology (2022) doi:10.1016/j.ejphar.2022.175013


Abstract: 

QX-314 is a quaternary permanently charged lidocaine derivative that inhibits voltage-gated sodium channels (NaV). As it is membrane impermeable, it is generally considered that QX-314 applied externally is inactive, unless it can gain access to the internal local anesthetic binding site via another entry pathway. Here, we characterized the electrophysiological effects of QX-314 on NaV1.7 heterologously expressed in HEK293 cells, and found that at high concentrations, external QX-314 inhibited NaV1.7 current (IC50 2.0 ± 0.3 mM) and shifted the voltage-dependence to more depolarized potentials (ΔV50 +10.6 mV). Unlike lidocaine, the activity of external QX-314 was not state- or use-dependent. The effect of externally applied QX-314 on NaV1.7 channel biophysics differed to that of internally applied QX-314, suggesting QX-314 has an additional externally accessible site of action. In line with this hypothesis, disruption of the local anesthetic binding site in a [F1748A]NaV1.7 mutant reduced the potency of lidocaine by 40-fold, but had no effect on the potency or activity of externally applied QX-314. Therefore, we conclude, using an expression system where QX-314 was unable to cross the membrane, that externally applied QX-314 is able to inhibit NaV1.7 peak current at low millimolar concentrations.


Download here

Back to Overview

We use cookies on our website. Some of them are essential for the operation of the site, while others help us to improve this site and the user experience (tracking cookies). You can decide for yourself whether you want to allow cookies or not. Please note that if you reject them, you may not be able to use all the functionalities of the site.