Colocalization of active KCa channels and Ca2+ channels within Ca2+ domains in helix neurons

Neuron. 1993 Apr;10(4):689-99. doi: 10.1016/0896-6273(93)90170-v.


Large conductance Ca(2+)-activated K+ channels (KCa channels) have to be colocalized with Ca2+ channels to be involved in nerve cell firing regulation. KCa channels were detected in cell-attached patches performed in voltage-clamped Helix neurons. This technique allowed Ca2+ entry to occur either within or around the patch. We observed that the submembrane Ca2+ diffusion was sufficiently limited to prevent the KCa channels from being opened by remote Ca2+ entry. The KCa channels located in areas devoid of Ca2+ channels remained quiescent during cell firing. These crypto channels were detected following either patch excision or intracellular Ca2+ injection. These data provide direct evidence for the existence of functional Ca2+ domains in a nonspecialized neural membrane.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium / metabolism
  • Calcium / physiology*
  • Calcium Channels / metabolism*
  • Calcium Channels / physiology
  • Diffusion
  • Electrophysiology
  • Helix, Snails / metabolism*
  • Neurons / metabolism*
  • Tissue Distribution


  • Calcium Channels
  • Calcium