Calcium entry through a subpopulation of AMPA receptors desensitized neighbouring NMDA receptors in rat dorsal horn neurons

J Physiol. 1995 Jun 1;485 ( Pt 2)(Pt 2):373-81. doi: 10.1113/jphysiol.1995.sp020736.


1. A Ca(2+)-dependent interaction between non-NMDA and NMDA receptors was studied in embryonic rat dorsal horn neurons grown in tissue culture using perforated-patch recording. Specifically, non-NMDA receptors were found to induce reversible inhibition of NMDA receptors in a manner dependent on the presence of extracellular Ca2+. 2. Non-NMDA receptor-induced inhibition of NMDA receptors was mediated by the elevation of intracellular Ca2+ concentration produced by Ca2+ entry through a subpopulation of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) non-NMDA receptors. Furthermore, Ca2+ entry through the AMPA channels alone is sufficient for desensitization of NMDA channels to occur. 3. Imaging of neuritic sites of Ca2+ revealed that Ca(2+)-permeable AMPA channels are often co-localized with NMDA channels on dorsal horn neurons, indicating that the Ca(2+)-mediated interaction between receptors may occur within small dendritic domains. 4. The ability of Ca(2+)-permeable AMPA channels to inhibit adjacent NMDA channels may contribute to the postsynaptic integration of excitatory input.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Calcium / metabolism*
  • Cells, Cultured
  • Electrophysiology
  • Kainic Acid / pharmacology
  • Neurites / drug effects
  • Neurites / metabolism
  • Neuronal Plasticity / drug effects
  • Neurons / metabolism*
  • Patch-Clamp Techniques
  • Rats
  • Receptors, AMPA / drug effects
  • Receptors, AMPA / metabolism*
  • Receptors, N-Methyl-D-Aspartate / antagonists & inhibitors
  • Receptors, N-Methyl-D-Aspartate / drug effects
  • Receptors, N-Methyl-D-Aspartate / metabolism*
  • Spinal Cord / cytology
  • Spinal Cord / metabolism*
  • alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / pharmacology


  • Receptors, AMPA
  • Receptors, N-Methyl-D-Aspartate
  • alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid
  • Kainic Acid
  • Calcium