Calcium-dependent inactivation of heteromeric NMDA receptor-channels expressed in human embryonic kidney cells

J Physiol. 1995 Feb 1;482 ( Pt 3)(Pt 3):567-73. doi: 10.1113/jphysiol.1995.sp020540.


1. Whole-cell current through heteromeric NR1-NR2A and NR1-NR2B subunit combinations of NMDA channels transiently expressed in human embryonic kidney cells (HEK 293) were studied using the patch-clamp technique. 2. With 4 mM Mg-ATP in the internal pipette solution, the responses of cells expressing NR1-NR2A channels to glutamate application gradually decreased, reaching 50% of control during the first 20 min of recording. This process was accompanied by acceleration of desensitization. 3. Conditioning (5-15 s) applications of glutamate (100 microM) induced a transient inactivation of NR1-NR2A and NR1-NR2B channels (20-40%) with a slow time course of recovery (tau r = 10-60 s). Both the degree of inactivation and the time constant of recovery increased with the duration of conditioning applications of glutamate, and with an elevation of Ca2+ in the external solution. 4. These results show that both NR1-NR2A and NR1-NR2B recombinant NMDA receptor-channels expressed in HEK 293 cells can be transiently inhibited by Ca2+ ions in a similar way to that described for hippocampal neurones.

MeSH terms

  • Calcium / physiology*
  • Cell Line
  • Glutamic Acid / pharmacology
  • Humans
  • Ion Channels / drug effects
  • Ion Channels / metabolism*
  • Kidney / cytology
  • Kidney / drug effects
  • Kidney / metabolism*
  • Patch-Clamp Techniques
  • Receptors, N-Methyl-D-Aspartate / drug effects
  • Receptors, N-Methyl-D-Aspartate / metabolism*
  • Recombinant Proteins / metabolism


  • Ion Channels
  • Receptors, N-Methyl-D-Aspartate
  • Recombinant Proteins
  • Glutamic Acid
  • Calcium