[Kinetics of the reaction between scorpion toxin and the sodium channels of nodes of Ranvier].

The kinetics of the scorpion Buthus eupeus venom toxin binding to sodium channels at holding potential -120 mV and subsequent dissociation of the toxin-channel complex with the membrane potential shifts to -60 divided by +120 mV were studied under voltage clamp conditions in the Ranvier node membrane. The dissociation rate is shown to increase exponentially when shifting the membrane potential towards more positive values, with an e-fold increase for each 32.3 mV. The results are consistent with the suggestion that the dissociation of the toxin-channel complex is due to a difference in electric energy between normal and toxin-modified inactivated sodium channels.