| Voltage gated sodium channels (Nav) are important elements of action potential initiation and propagation in excitable cells because they are responsible for the initial depolarization of the membrane. |
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| Whole cell recordings performed with the Patchliner. Whole cell currents of HEK293 cells stably expressing hNav1.5. |
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| Stable recordings. A series of drug concentrations can be applied to one cell. Figure A shows Imax (-40 mV) as recorded in Nav1.5 expressing CHO cells. Five concentrations of TTX (0.3, 1, 3, 10, 30 μM) have been applied, then washed out and applied again to demonstrate the stability of whole cell recordings. |
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Block of the hNav1.5 by lidocaine is voltage dependent. Full dose response curves at the different holding potentials were recorded for each cell (HEK293 cells stably expressing hNav1.5). Currents were elicited every 2 s by a 10 ms voltage step to 0 mV. Plotted are average peak currents as a function of the holding potential and the lidocaine concentration. The IC50s for lidocaine were 1.7 µM (-70 mV), 4.0 µM (-80 mV), 21.7 µM (-90 mV), 37.8 µM (-100 mV), and 194.6 µM (-110 mV). |