Currents from squid giant axons clamped with their action potentials

摘要

The Hodgkin-Huxley equations1 have been used extensively to derive currents through membranes of squid giant axon. The Hodgkin-Huxley model postulates two independent ensembles of molecular channels which become accessible to K+ and Na+ ion currents respectively when they change from a closed to an open configuration. The membrane conductance is directly proportional to the number of “open” channels in each ensemble. With this arrangement, the current-voltage relationship is ohmic although the membrane conductance increases as the number of open channels increases. The rate constants for the closed-open kinetics are functions of the transmembrane potential.