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

• Published in: The Journal of physiology Vol. 485; no. Pt 2; pp. 373 - 381
• Main Authors: Kyrozis, A, Goldstein, P A, Heath, M J, MacDermott, A B
• Format: Journal Article
• Language: English
• Published: England The Physiological Society 01.06.1995
• Subjects: alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid - pharmacology; 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
• ISSN: 0022-3751; 1469-7793
• 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.