Rapid recovery from K current inactivation on membrane hyperpolarization in molluscan neurons

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• Alternative Title:
  J Gen Physiol
• Description:
  Recovery from K current inactivation was studied in molluscan neurons using two-microelectrode and internal perfusion voltage clamps. Experiments were designed to study the voltage-dependent delayed outward current (IK) without contamination from other K currents. The amount of recovery from inactivation and the rate of recovery increase dramatically when the membrane potential is made more negative. The time course of recovery at the resting potential, -40 mV, is well fit by a single exponential with a time constant of 24.5 s (n = 7). At more negative voltages, the time course is best fit by the sum of two exponentials with time constants at -90 mV of 1.7 and 9.8 s (n = 7). In unclamped cells, a short hyperpolarization can cause rapid recovery from inactivation that results in a shortening of the action potential duration. We conclude that there are two inactivated states of the channel and that the time constants for recovery from both states are voltage dependent. The results are discussed in terms of the multistate model for K channel gating that was developed by R. N. Aldrich (1981, Biophys. J., 36:519-532).
• Subjects:
  Action Potentials Animals Electric Stimulation Ion Channels Kinetics Membrane Potentials Microelectrodes Models, Biological Neurons Potassium Snails

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• Source:
  J Gen Physiol. 84(6):861-875.
• Pubmed ID:
  6097637
• Pubmed Central ID:
  PMC2228767
• Document Type:
  Journal Article
• Funding:
  ND 14519/ND/ONDIEH CDC HHS/United States
• Volume:
  84
• Issue:
  6
• Collection(s):
  CDC Public Access
• Main Document Checksum:
  urn:sha256:de314058697bf780fbfe7701687e004027f607887a21cf7c91b648e975772dcb
• Download URL:
  https://stacks.cdc.gov/view/cdc/30806/cdc_30806_DS1.pdf
• File Type:
  [PDF - 849.98 KB ]