Fractionation of the asymmetry current in the squid giant axon into inactivating and non-inactivating components.
The operation of the voltage-sensitive sodium gating system in the nerve membrane involves conformational changes that are accompanied by small asymmetrical displacement currents. The asymmetry current may be divided into a component that is inactivated by positive voltage-clamp pulses, and recovers from inactivation with exactly the same time course as the sodium conductance, and one that is not inactivated. A method is described for recording the two components separately with the aid of an inactivating prepulse. They appear to have a marked difference in their rising phases, that of the non-inactivating component being just about as fast as the imposed step in membrane potential, while the inactivating component requires some tens of microseconds to reach its peak.
D000818:Animals; D001369:Axons / Q000502:physiology*; D049832:Decapodiformes; D004553:Electric Conductivity; D007473:Ion Channels / Q000502:physiology; D008564:Membrane Potentials; D012964:Sodium / Q000502:physiology*
D007473:Ion Channels; D012964:Sodium