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Modulation of the Potassium Conductance in the Squid Giant Axon

  • Eduardo Perozo
  • Christina K. Webb
  • Francisco Bezanilla

Abstract

The potassium conductance of the squid giant axon is considered the classical example of the delayed rectifier-type of voltage dependent potassium permeability (Hodgkin and Huxley, 1952). In this preparation a large number of experiments have been done on K ionic currents using intact axons and under conditions of internal perfusion to study the selectivity and voltage dependence of the conductance. It has also been possible to record single channel events (Conti and Neher, 1980; Llano and Bezanilla, 1985; Llano, Webb and Bezanilla, 1987) and gating currents related to the movement of the charge responsible for the opening and closing of the K conductance (White and Bezanilla, 1985). The squid giant axon is then an ideal preparation for a detailed analysis of K channel gating because all types of electrophysiological recordings can be made in the same preparation, an important prerequisite for formulating a complete model of channel gating. We review here evidence that the K conductance in the squid axon is modulated by ATP-dependent phosphorylation. The changes induced by ATP in the macroscopic currents appear to be the result of a combined effect on more than one type of K channel. We also provide evidence for a Ca-activated component of the K conductance.

Keywords

Current Amplitude Voltage Dependence Internal Solution Voltage Shift Potassium Conductance 
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

© Plenum Press, New York 1988

Authors and Affiliations

  • Eduardo Perozo
    • 2
    • 3
    • 1
  • Christina K. Webb
    • 2
    • 1
  • Francisco Bezanilla
    • 2
    • 1
  1. 1.Marine Biological LaboratoryWoods HoleUSA
  2. 2.Department of Physiology, Ahmanson Laboratory of Neurobiology and Jerry Lewis Neuromuscular Research CenterUniversity of CaliforniaLos AngelesUSA
  3. 3.Instituto Venezolano de Investigaciones CientificasCaracasVenezuela

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