An unexpected role for TASK-3 potassium channels in network oscillations with implications for sleep mechanisms and anesthetic action

Proc Natl Acad Sci U S A. 2009 Oct 13;106(41):17546-51. doi: 10.1073/pnas.0907228106. Epub 2009 Sep 24.

Abstract

TASK channels are acid-sensitive and anesthetic-activated members of the family of two-pore-domain potassium channels. We have made the surprising discovery that the genetic ablation of TASK-3 channels eliminates a specific type of theta oscillation in the cortical electroencephalogram (EEG) resembling type II theta (4-9 Hz), which is thought to be important in processing sensory stimuli before initiating motor activity. In contrast, ablation of TASK-1 channels has no effect on theta oscillations. Despite the absence of type II theta oscillations in the TASK-3 knockout (KO) mice, the related type I theta, which has certain neuronal pathways in common and is involved in exploratory behavior, is unaffected. In addition to the absence of type II theta oscillations, the TASK-3 KO animals show marked alterations in both anesthetic sensitivity and natural sleep behavior. Their sensitivity to halothane, a potent activator of TASK channels, is greatly reduced, whereas their sensitivity to cyclopropane, which does not activate TASK-3 channels, is unchanged. The TASK-3 KO animals exhibit a slower progression from their waking to sleeping states and, during their sleeping period, their sleep episodes as well as their REM theta oscillations are more fragmented. These results imply a previously unexpected role for TASK-3 channels in the cellular mechanisms underlying these behaviors and suggest that endogenous modulators of these channels may regulate theta oscillations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Circadian Rhythm / genetics
  • Circadian Rhythm / physiology
  • Electroencephalography
  • Electromyography
  • Genotype
  • Mice
  • Mice, Knockout
  • Oscillometry
  • Potassium Channels, Tandem Pore Domain / deficiency
  • Potassium Channels, Tandem Pore Domain / genetics*
  • Sleep / physiology*
  • Wakefulness / physiology

Substances

  • Potassium Channels, Tandem Pore Domain