Effect of water-soluble carbodiimide on gating in sodium channels

Abstract

The treatment of nodal membrane with water-soluble carbodiimide results in a deceleration of the time-course of activation and inactivation of Na + channels and in a decrease in the steepness of the voltage-dependence of the channel gating. The effective charge of activation decreases from about 5 to 3 electronic charges. Carbodiimide is effective only at low (4.3–4.9) pH, which means that it reacts most probably with carboxyl groups. The data are consistent with the proposal that carboxyl groups may serve as ‘gating particles’.