Known calcium channel alpha1 subunits can form low threshold small conductance channels with similarities to native T-type channels

Neuron. 1998 Feb;20(2):341-51. doi: 10.1016/s0896-6273(00)80461-4.


Native T-type voltage-dependent calcium channels are low voltage-activated and have a small single channel conductance of 5-8 pS, which distinguishes them from any known cloned calcium channels whose conductances are 12-25 pS. Here, we show that when alpha1B, alpha1E, or alpha1C are expressed in COS7 cells, which contain no endogenous calcium channel subunits or calcium channels, they each exhibit a 4-7 pS channel as well as a large conductance channel. At low depolarizations, or when the alpha1 subunit is expressed in the absence of auxiliary alpha2-delta or beta subunits, the small conductance channels are seen alone, and their biophysical properties, including voltage dependence and kinetics of activation and inactivation, are very similar to native T-type calcium channels.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • COS Cells
  • Calcium Channels / chemistry*
  • Calcium Channels / genetics*
  • Electric Conductivity
  • Gene Expression
  • Glioma
  • Hybrid Cells / chemistry
  • Hybrid Cells / physiology
  • Ion Channel Gating / drug effects
  • Ion Channel Gating / physiology*
  • Neuroblastoma
  • Patch-Clamp Techniques
  • Rats
  • Transfection


  • Calcium Channels