Nav1.5 use-dependent blockers on QPatch X

The voltage dependent sodium channel, Na_V1.5, was tested on QPatch 16X in single-hole and multi-hole mode. Single-hole mode is a classic patch clamp experiment where one cell is in whole-cell configuration, whereas multi-hole mode comprises up to 10 cells in whole-cell configuration. The multi-hole mode therefore tests the summed current of up to ten cells.
In this study, we wanted to determine the best test protocol to distinguish between two antiarrythmic drugs with different modes of action: flecainide, which blocks open Na_v channels, and lidocaine, which blocks inactivated Na_v channels. Therefore four different voltage protocols were set up to test for: 1) steady-state inactivation, 2) open-channel block, 3) recovery from inactivation, 4) state- versus use-dependence. Each protocol was tested in both single-hole and multi-hole mode to compare the capabilities of the QPatch 16X in the two modes.