Summary
The properties of various potassium conductance models have been investigated using an analogue computer. It is shown that the experimental data of Hodgkin and Huxley can be fitted as satisfactorily by a cube (n 3) model of potassium conductance as it is by the Hodgkin-Huxley (n 4) and (n 6) models.
A planar subunit array structure for the membrane has been suggested, where the appearance of a potassium conducting channel depends upon a conformational change to an activated state in each of δ neighboring subunits. This system is described by the same mathematics as the Hodgkin-Huxley activating particle mechanism and so provides a physical basis for the power (n δ) formulae. Introduction of interaction between subunits, such that a conformational change is prohibited unless an adjacent subunit is in the activated state, modifies the mathematics and enables simulation of the delayed potassium currents observed by Cole and Moore (Biophys. J. 1:1, 1960). This innovation avoids the difficulties associated with the higher power (δ>6) models, by not requiring physical justification for large numbers of simultaneous events, while still providing a good fit to the experimental data. The interactive subunit models satisfactorily describe the potassium conductance changes which occur under voltage clamp or during an action potential.
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Bretag, A.H., Davis, B.R. & Kerr, D.I.B. Potassium conductance models related to an interactive subunit membrane. J. Membrain Biol. 16, 363–380 (1974). https://doi.org/10.1007/BF01872424
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DOI: https://doi.org/10.1007/BF01872424