title: Calcium-dependent inactivation of heteromeric NMDA receptor-channels expressed in human embryonic kidney cells.
abstract: 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.
authors.affiliation: INSERM, Unite 29 Hospital de Port-Royal, Paris, France.
authors.forename: I
authors.initials: I
authors.lastname: Medina
authors.forename: N
authors.initials: N
authors.lastname: Filippova
authors.forename: G
authors.initials: G
authors.lastname: Charton
authors.forename: S
authors.initials: S
authors.lastname: Rougeole
authors.forename: Y
authors.initials: Y
authors.lastname: Ben-Ari
authors.forename: M
authors.initials: M
authors.lastname: Khrestchatisky
authors.forename: P
authors.initials: P
authors.lastname: Bregestovski
mesh_terms: D002118:Calcium / Q000502:physiology*; D002460:Cell Line; D018698:Glutamic Acid / Q000494:pharmacology; D006801:Humans; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism*; D007668:Kidney / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism
chemical_list: D007473:Ion Channels; D016194:Receptors, N-Methyl-D-Aspartate; D011994:Recombinant Proteins; D018698:Glutamic Acid; D002118:Calcium