Tags

Type your tag names separated by a space and hit enter

Calcium-dependent inactivation of recombinant N-methyl-D-aspartate receptors is NR2 subunit specific.
Mol Pharmacol. 1996 Dec; 50(6):1680-8.MP

Abstract

Intracellular Ca2+ can reversibly reduce the activity of native N-methyl-D-aspartate (NMDA) receptors in hippocampal neurons, a phenomenon termed Ca2+-dependent inactivation. We examined inactivation in heteromeric NMDA receptors expressed in human embryonic kidney (HEK) 293 cells using whole-cell recording. NR1-1a/2A heteromers showed reversible inactivation that was very similar to native NMDA receptors in cultured hippocampal neurons. Inactivation was dependent on the extracellular Ca2+ concentration and the degree of intracellular Ca2+ buffering. In 2 mM extracellular Ca2+, inactivation resulted in a 46.1 +/- 12.6% reduction in the whole-cell current during a 5-sec agonist application. Inactivation of NR1-1a/2A heteromers was unaffected by calcineurin inhibitors, staurosporine, or phalloidin. NR1-1a/2D heteromers also showed a similar degree of inactivation. In contrast, NR1-1a/2B and NR1-1a/2C heteromers showed no significant inactivation. At saturating concentrations of NMDA (1 mM), NR1-1a/2A heteromers also showed Ca- and glycine-independent desensitization, as seen in native hippocampal neurons. Ca(2+)- and glycine-independent desensitization was less pronounced in NR1-1a/2B heteromers and absent in NR1-1a/2C heteromers. Activation of NR1-1a/2C heteromers triggered intracellular Ca2+ transients similar to NR1-1a/2A heteromers as verified by combined Ca2+ imaging and whole-cell recording. Thus differences in Ca2+ permeability were not responsible for the lack of inactivation in NR1-1a/2C heteromers. Our results show that inactivation of recombinant NMDA receptors requires either the NR2A or NR2D subunit, whereas both inactivation and desensitization were absent in NR2C-containing receptors. The gating of inactivating NMDA receptors is more likely to be influenced by ongoing NMDA receptor activity and Ca2+ transients, perhaps consistent with the prominent expression of NR2A in hippocampus and cerebral cortex.

Authors+Show Affiliations

Vollum Institute, Oregon Health Sciences University, Portland 97201, USA.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

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

Language

eng

PubMed ID

8967993

Citation

Krupp, J J., et al. "Calcium-dependent Inactivation of Recombinant N-methyl-D-aspartate Receptors Is NR2 Subunit Specific." Molecular Pharmacology, vol. 50, no. 6, 1996, pp. 1680-8.
Krupp JJ, Vissel B, Heinemann SF, et al. Calcium-dependent inactivation of recombinant N-methyl-D-aspartate receptors is NR2 subunit specific. Mol Pharmacol. 1996;50(6):1680-8.
Krupp, J. J., Vissel, B., Heinemann, S. F., & Westbrook, G. L. (1996). Calcium-dependent inactivation of recombinant N-methyl-D-aspartate receptors is NR2 subunit specific. Molecular Pharmacology, 50(6), 1680-8.
Krupp JJ, et al. Calcium-dependent Inactivation of Recombinant N-methyl-D-aspartate Receptors Is NR2 Subunit Specific. Mol Pharmacol. 1996;50(6):1680-8. PubMed PMID: 8967993.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Calcium-dependent inactivation of recombinant N-methyl-D-aspartate receptors is NR2 subunit specific. AU - Krupp,J J, AU - Vissel,B, AU - Heinemann,S F, AU - Westbrook,G L, PY - 1996/12/1/pubmed PY - 1996/12/1/medline PY - 1996/12/1/entrez SP - 1680 EP - 8 JF - Molecular pharmacology JO - Mol Pharmacol VL - 50 IS - 6 N2 - Intracellular Ca2+ can reversibly reduce the activity of native N-methyl-D-aspartate (NMDA) receptors in hippocampal neurons, a phenomenon termed Ca2+-dependent inactivation. We examined inactivation in heteromeric NMDA receptors expressed in human embryonic kidney (HEK) 293 cells using whole-cell recording. NR1-1a/2A heteromers showed reversible inactivation that was very similar to native NMDA receptors in cultured hippocampal neurons. Inactivation was dependent on the extracellular Ca2+ concentration and the degree of intracellular Ca2+ buffering. In 2 mM extracellular Ca2+, inactivation resulted in a 46.1 +/- 12.6% reduction in the whole-cell current during a 5-sec agonist application. Inactivation of NR1-1a/2A heteromers was unaffected by calcineurin inhibitors, staurosporine, or phalloidin. NR1-1a/2D heteromers also showed a similar degree of inactivation. In contrast, NR1-1a/2B and NR1-1a/2C heteromers showed no significant inactivation. At saturating concentrations of NMDA (1 mM), NR1-1a/2A heteromers also showed Ca- and glycine-independent desensitization, as seen in native hippocampal neurons. Ca(2+)- and glycine-independent desensitization was less pronounced in NR1-1a/2B heteromers and absent in NR1-1a/2C heteromers. Activation of NR1-1a/2C heteromers triggered intracellular Ca2+ transients similar to NR1-1a/2A heteromers as verified by combined Ca2+ imaging and whole-cell recording. Thus differences in Ca2+ permeability were not responsible for the lack of inactivation in NR1-1a/2C heteromers. Our results show that inactivation of recombinant NMDA receptors requires either the NR2A or NR2D subunit, whereas both inactivation and desensitization were absent in NR2C-containing receptors. The gating of inactivating NMDA receptors is more likely to be influenced by ongoing NMDA receptor activity and Ca2+ transients, perhaps consistent with the prominent expression of NR2A in hippocampus and cerebral cortex. SN - 0026-895X UR - https://www.unboundmedicine.com/medline/citation/8967993/Calcium_dependent_inactivation_of_recombinant_N_methyl_D_aspartate_receptors_is_NR2_subunit_specific_ L2 - http://molpharm.aspetjournals.org/cgi/pmidlookup?view=long&pmid=8967993 DB - PRIME DP - Unbound Medicine ER -