In Vitro Assay: HEK 293 cells stably transfected with either Nav 1.7 or with Nav 1.5 were recorded in population patch-clamp mode with the IonWorks® Quattro automated electrophysiology system in accordance with the manufacturer's specifications (Molecular Devices, LLC, Sunnyvale, Calif.). Sodium channel currents were measured in response to a train of depolarizations that induced successively greater inactivation. Cells were held at −110 mV for three seconds (Nav 1.7) or half a second (Nav 1.5) from a holding voltage of −15 mV, then put through a series of 26 pulses of 150 msec duration to −20 mV at a frequency of 5 Hz. Cells were then left unclamped for a period of 3 to 8 minutes while a single concentration of test compound was added. Cells were then reclamped and put through the same voltage protocol. Current at the end of the 26th pulse to −20 mV was subtracted from the peak current evoked by the 26th pulse to −20 mV to correct for leak current.
In Vitro PX Assay: HEK 293 cells stably transfected with human Nav1.7 were recorded in whole cell voltage clamp mode with the PatchXpress automated electrophysiology system (Molecular Devices, LLC, Sunnyvale, Calif.). Compound effects were measured on a partially inactivated state of the sodium channel. Cells were clamped to a holding potential yielding 20 to 50% inactivation. To elicit sodium current, channels were activated by pulsing to −10 mV for 20 msec. This voltage protocol was repeated at a rate of 0.1 Hz throughout the experiment. A single concentration of test compound was applied to cells for a duration of 3 minutes.
In Vitro Assay: HEK 293 cells stably transfected with either Nav 1.7 or with Nav 1.5 were recorded in population patch-clamp mode with the IonWorks® Quattro automated electrophysiology system in accordance with the manufacturer's specifications (Molecular Devices, LLC, Sunnyvale, Calif.). Sodium channel currents were measured in response to a train of depolarizations that induced successively greater inactivation. Cells were held at −110 mV for three seconds (Nav 1.7) or half a second (Nav 1.5) from a holding voltage of −15 mV, then put through a series of 26 pulses of 150 msec duration to −20 mV at a frequency of 5 Hz. Cells were then left unclamped for a period of 3 to 8 minutes while a single concentration of test compound was added. Cells were then reclamped and put through the same voltage protocol. Current at the end of the 26th pulse to −20 mV was subtracted from the peak current evoked by the 26th pulse to −20 mV to correct for leak current.
Inhibition of NaV1.8 in rat DRG neurons assessed as reduction in tetrodotoxin-sensitive sodium channel currents at holding potential of -140 mV by manual patch clamp electrophysiology assay
Inhibition of NaV1.8 in C57BL/6 mouse DRG neurons assessed as reduction in tetrodotoxin-sensitive sodium channel currents at holding potential of -140 mV by manual patch clamp electrophysiology assay