SK2 and SK3 expression differentially affect firing frequency and precision in dopamine neurons

Neuroscience. 2012 Aug 16:217:67-76. doi: 10.1016/j.neuroscience.2012.04.053. Epub 2012 Apr 30.


The firing properties of dopamine (DA) neurons in the substantia nigra (SN) pars compacta are strongly influenced by the activity of apamin-sensitive small conductance Ca(2+)-activated K(+) (SK) channels. Of the three SK channel genes expressed in central neurons, only SK3 expression has been identified in DA neurons. The present findings show that SK2 was also expressed in DA neurons. Immuno-electron microscopy (iEM) showed that SK2 was primarily expressed in the distal dendrites, while SK3 was heavily expressed in the soma and, to a lesser extent, throughout the dendritic arbor. Electrophysiological recordings of the effects of the SK channel blocker apamin on DA neurons from wild type and SK(-/-) mice show that SK2-containing channels contributed to the precision of action potential (AP) timing, while SK3-containing channels influenced AP frequency. The expression of SK2 in DA neurons may endow distinct signaling and subcellular localization to SK2-containing channels.

Publication types

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

MeSH terms

  • Action Potentials / drug effects
  • Action Potentials / physiology*
  • Animals
  • Apamin / pharmacology
  • Dopaminergic Neurons / drug effects
  • Dopaminergic Neurons / metabolism
  • Dopaminergic Neurons / physiology*
  • Mice
  • Mice, Knockout
  • Small-Conductance Calcium-Activated Potassium Channels / genetics
  • Small-Conductance Calcium-Activated Potassium Channels / metabolism*
  • Substantia Nigra / drug effects
  • Substantia Nigra / metabolism


  • Kcnn2 protein, mouse
  • Kcnn3 protein, mouse
  • Small-Conductance Calcium-Activated Potassium Channels
  • Apamin