PF-04856264, is a synthetic blocker of the human NaV1.7 channel. It has an effective concentration of 10 nM - 1 μM and an IC50 of 28 nM for NaV1.7 channel in its inactive state. NaV1.7 currents elicited by 20 ms depolarizing voltage steps from −120 mV are insensitive to inhibition by 1 µM PF-04856264, whereas the same concentration produced 91% ± 4% inhibition when a test pulse was preceded by an 8-s conditioning voltage step to inactivate approximately half of the channels. In contrast, NaV1.3 and NaV1.5 channels exhibit little or no sensitivity to inhibition by PF-04856264.
