Strong voltage-dependent inward rectification of inward rectifier K+ channels is caused by intracellular spermine

Cell. 1995 Jan 13;80(1):149-54. doi: 10.1016/0092-8674(95)90459-x.


Inward rectifier K+ channels mediate the K+ conductance at resting potential in many types of cell. Since these K+ channels do not pass outward currents (inward rectification) when the cell membrane is depolarized beyond a trigger threshold, they play an important role in controlling excitability. Both a highly voltage-dependent block by intracellular Mg2+ and an endogenous gating process are presently assumed to underly inward rectification. It is shown that strong voltage dependence of rectification found under physiological conditions is predominantly due to the effect of intracellular spermine. Physiological concentrations of free spermine mediate strong rectification of IRK1 inward rectifier K+ channels even in the absence of free Mg2+ and in IRK1 mutant channels that have no endogenous rectification.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Ion Channel Gating
  • Magnesium / metabolism
  • Membrane Potentials
  • Oocytes
  • Patch-Clamp Techniques
  • Potassium Channels / metabolism*
  • Potassium Channels, Inwardly Rectifying*
  • Spermine / metabolism*
  • Xenopus


  • Potassium Channels
  • Potassium Channels, Inwardly Rectifying
  • Spermine
  • Magnesium