NaV1.5 - "Pharmacology of hNaV1.5 recorded on Nanion's Patchliner"
Voltage gated sodium channels (NaV) are important elements of action potential initiation and propagation in excitable cells. The channels are activated upon a depolarization of the membrane. Their activation leads to further depolarization of the membrane which constitutes the upstroke of the action potential. NaV currents generally activate very fast (within 1-2 ms) upon depolarization of the membrane. Hence, a good and stable access resistance is critical for high quality pharmacological patch clamp recordings. Also, for automated patch clamp devices, it is not a given that applied compound concentrations are accurately delivered to the cell. This is a pre-requisite for accurately reproducible dose-response curves. Here we present data collected on the 8-channel Patchliner. Tetrodotoxin and lidocaine dose‑response curves on hNaV1.5 expressed in HEK293 cells are shown. Lidocaine has been shown to block hNaV1.5 in its inactivated state (Bean et al. 1983) which means that the IC50 of lidocaine becomes dependent on the holding potential. This dependence was investigated. We also demonstrate the stability and reproducibility of the data collected with the Patchliner. Using two sequential dose responses of hNaV1.5 to TTX we demonstrate that the compound concentrations are accurately delivered to the cells and that recordings are stable with robust access resistance.