Fast delayed rectifier potassium current is required for circadian neural activity

Nat Neurosci. 2005 May;8(5):650-6. doi: 10.1038/nn1448. Epub 2005 Apr 24.


In mammals, the precise circadian timing of many biological processes depends on the generation of oscillations in neural activity of pacemaker cells in the suprachiasmatic nucleus (SCN). The ionic mechanisms that underlie these rhythms are largely unknown. Using the mouse brain slice preparation, we show that the magnitude of fast delayed rectifier (FDR) potassium currents has a diurnal rhythm that peaks during the day. Notably, this rhythm continues in constant darkness, providing the first demonstration of the circadian regulation of an intrinsic voltage-gated current in mammalian cells. Blocking this current prevented the daily rhythm in firing rate in SCN neurons. Kv3.1b and Kv3.2 potassium channels were widely distributed within the SCN, with higher expression during the day. We conclude that the FDR is necessary for the circadian modulation of electrical activity in SCN neurons and represents an important part of the ionic basis for the generation of rhythmic output.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Action Potentials / physiology*
  • Animals
  • Biological Clocks / drug effects
  • Biological Clocks / physiology*
  • Circadian Rhythm / drug effects
  • Circadian Rhythm / physiology*
  • Darkness
  • Delayed Rectifier Potassium Channels
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Neurons / drug effects
  • Neurons / physiology*
  • Organ Culture Techniques
  • Potassium Channels, Voltage-Gated / drug effects
  • Potassium Channels, Voltage-Gated / metabolism
  • Potassium Channels, Voltage-Gated / physiology*
  • Shaw Potassium Channels
  • Suprachiasmatic Nucleus / drug effects
  • Suprachiasmatic Nucleus / physiology*
  • Synaptic Transmission / drug effects
  • Synaptic Transmission / physiology


  • Delayed Rectifier Potassium Channels
  • Kcnc1 protein, mouse
  • Potassium Channels, Voltage-Gated
  • Shaw Potassium Channels