Royal Society Publishing

Fractionation of the Asymmetry Current in the Squid Giant Axon into Inactivating and Non-Inactivating Components

N. G. Greeff, R. D. Keynes, D. F. Van Helden


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.

Royal Society Login

Log in through your institution