A potassium conductance activated by hyperpolarization in paramecium

J Membr Biol. 1978 Oct 19;43(2-3):169-85. doi: 10.1007/BF01933477.

Abstract

Voltage clamp studies show that the wild-type membrane of Paramecium tetraurelia contains a conductance component which is sensitive to hyperpolarization. This component manifests itself as "anomalous", or "inward going", rectification of membrane voltage in response to applied constant current pulses and as a "hyperpolarizing spike" when no K is added to the external solution (Y. Satow, C. Kung, 1977. J. Comp. Physiol. 119:99). Like the conductances which underlie anomalous rectification in other cells, the hyperpolarization-sensitive conductance in Paramecium is specific for K, and the magnitude of the voltage-dependent conductance change depends not only on voltage but also on external potassium concentration. The internal potassium ion concentration of Paramecium is calculated to be between 17 and 18mM.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Cell Membrane Permeability
  • Electric Conductivity
  • Ion Channels / physiology*
  • Membrane Potentials
  • Paramecium / physiology*
  • Potassium / physiology*

Substances

  • Ion Channels
  • Potassium