Fast delayed rectifier potassium current is required for circadian neural activity.
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.
Itri
Jason N
JN
Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, 760 Westwood Plaza, Los Angeles, California 90024-1759, USA.
Michel
Stephan
S
Vansteensel
Mariska J
MJ
Meijer
Johanna H
JH
Colwell
Christopher S
CS
D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D001683:Biological Clocks / Q000187:drug effects / Q000502:physiology*; D002940:Circadian Rhythm / Q000187:drug effects / Q000502:physiology*; D003624:Darkness; D051668:Delayed Rectifier Potassium Channels; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D009924:Organ Culture Techniques; D024642:Potassium Channels, Voltage-Gated / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D051670:Shaw Potassium Channels; D013493:Suprachiasmatic Nucleus / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology
D051668:Delayed Rectifier Potassium Channels; C490839:Kcnc1 protein, mouse; D024642:Potassium Channels, Voltage-Gated; D051670:Shaw Potassium Channels