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
Article

Summary

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.

Keywords

Human Physiology Harmonic Analysis Rate Process Wide Band Nonlinear Model 

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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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