The Journal of Membrane Biology

, Volume 54, Issue 2, pp 157–164 | Cite as

Small-signal analysis of K+ conduction in squid axons

  • L. E. Moore
  • H. M. Fishman
  • D. J. M. Poussart


The maximum potential displacement that gives a linear K conductance response was determined to be 1 mV (rms) from a voltage-clamp analysis of TTX treated axons. For perturbations below this amplitude the K conductance kinetics are indistinguishable from a first-order rate process. Linearity and order of kinetics were assessed by four types of measurements: (i) the shape of the onset of the potassium current (sigmoidalvs. exponential); (ii) the symmetry of small hyperpolarizing and depolarizing pulses, (iii) wide band admittance, and (iv) harmonic analysis. The simplest interpretation of the results is that the small-signal linear response arises from a first-order gating mechanism, whereas the large-signal conventional voltage-clamp pulse of tens of millivolts evokes nonlinear phenomena. The small-signal results are consistent with the Hodgkin-Huxley description or any other nonlinear model which fits the large signal data and produces a linear first-order response for small perturbations.


Human Physiology Harmonic Analysis Rate Process Wide Band Nonlinear Model 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag New York Inc 1980

Authors and Affiliations

  • L. E. Moore
    • 1
  • H. M. Fishman
    • 1
  • D. J. M. Poussart
    • 1
  1. 1.Marine Biological LaboratoryWoods Hole

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