Pharmacological properties of recombinant N-methyl-D-aspartate (NMDA) receptors containing the epsilon 4 (NR2D) subunit

Neurosci Lett. 1995 Jan 30;184(3):181-4. doi: 10.1016/0304-3940(94)11201-s.


The modulatory effects of spermine, histamine, and ifenprodil on recombinant N-methyl-D-aspartate (NMDA) receptors expressed from the NR1A and epsilon 4 (NR2D) subunits were studied by voltage-clamp recording in Xenopus oocytes. Spermine had no effect on responses to glutamate and glycine at NR1A/epsilon 4 receptors. None of the four previously described effects of spermine, all of which are seen at NR1A receptors and at NR1A/NR2B receptors, was seen at NR1A/epsilon 4 receptors. Similarly, NR1A/epsilon 4 receptors were insensitive to potentiation by histamine and to blockade by ifenprodil. The properties of NR1A/epsilon 4 receptors thus resemble those of NR1A/NR2C receptors and are markedly different from those of homomeric NR1A receptors. In heteromeric NR1A/epsilon 4 receptors the epsilon 4 subunit may alter properties associated with the NR1A subunit, as has been previously suggested for NR2A, NR2B, and NR2C subunits in NR1A/NR2 receptors.

MeSH terms

  • Animals
  • Glutamic Acid / pharmacology
  • Glycine / pharmacology
  • Histamine / pharmacology*
  • Oocytes
  • Piperidines / pharmacology*
  • Receptors, N-Methyl-D-Aspartate / chemistry*
  • Receptors, N-Methyl-D-Aspartate / drug effects*
  • Recombinant Proteins
  • Spermine / pharmacology*
  • Xenopus laevis


  • Piperidines
  • Receptors, N-Methyl-D-Aspartate
  • Recombinant Proteins
  • Spermine
  • Glutamic Acid
  • Histamine
  • ifenprodil
  • Glycine