Overview
Huwentoxin-IV (HWTX-IV), a tetrodotoxin-sensitive (TTX-s) Na+ channel blocker, isolated from the venom of the Chinese Bird spider Ornithoctonus huwena1. A naturally modified HWTX-IV (mHWTX-IV), having a molecular mass 18 Da. lower than HWTX-IV, has also been isolated from the venom of the same spider. mHWTX-IV has been shown to have the same amino acid sequence as that of HWTX-IV, except that the N-terminal glutamic acid is replaced by pyroglutamic acid. mHWTX-IV inhibits tetrodotoxin-sensitive NaV channels of dorsal root ganglion neurons with an IC50 nearly equal to native HWTX-IV (IC50 value of 28 nM versus 26 nM). mHWTX-IV shows the same activation and inactivation kinetics seen for native HWTX-IV2.
Huwentoxin-IV preferentially inhibits hNaV1.7. NaV1.7 plays a crucial role in pain transduction with familial gain of function mutations linked to several chronic pain disorders, while loss of NaV1.7 function results in congenital insensitivity to pain3.
Specifications
Applications
Alomone Labs mHuwentoxin-IV inhibits NaV1.7 currents in stably transfected HEK cells.A. Time course of mHuwentoxin-IV (#STH-101) action on NaV1.7 currents. Maximum current amplitudes were plotted as a function of time. Membrane potential was held at –100 mV and cells were stimulated by a 50 ms voltage ramp to +20 mV. 100 nM mHuwentoxin-IV were perfused as indicated by the bar (green) during 4 min. B. Superimposed examples of NaV1.7 channel current in the absence (control) and presence (green) of 100 nM mHuwentoxin-IV (taken from the experiment in A).
