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The NMDA-to-AMPA ratio at synapses onto layer 2/3 pyramidal neurons is conserved across prefrontal and visual cortices.
J Neurophysiol. 2003 Aug; 90(2):771-9.JN

Abstract

To better understand regulation of N-methyl-d-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor complements across the cortex, and to investigate NMDA receptor (NMDAR)-based models of persistent activity, we compared NMDA/AMPA ratios in prefrontal (PFC) and visual cortex (VC) in rat. Whole cell voltage-clamp responses were recorded in brain slices from layer 2/3 pyramidal cells of the medial PFC and VC of rats aged p16-p21. Mixed miniature excitatory postsynaptic currents (mEPSCs) having AMPA receptor (AMPAR)- and NMDAR-mediated components were isolated in nominally 0 Mg2+ ACSF. Averaged mEPSCs were well-fit by double exponentials. No significant differences in the NMDA/AMPA ratio (PFC: 27 +/- 1%; VC: 28 +/- 3%), peak mEPSC amplitude (PFC: 19.1 +/- 1 pA; VC: 17.5 +/- 0.7 pA), NMDAR decay kinetics (PFC: 69 +/- 8 ms; VC: 67 +/- 6 ms), or degree of correlation between NMDAR- and AMPAR-mediated mEPSC components were found between the areas (PFC: n = 27; VC: n = 28). Recordings from older rats (p26-29) also showed no differences. EPSCs were evoked extracellularly in 2 mM Mg2+ at depolarized potentials; although the average NMDA/AMPA ratio was larger than that observed for mEPSCs, the ratio was similar in the two regions. In nominally 0 Mg2+ and in the presence of CNQX, spontaneous activation of NMDAR increased recording noise and produced a small tonic depolarization which was similar in both areas. We conclude that this basic property of excitatory transmission is conserved across PFC and VC synapses and is therefore unlikely to contribute to differences in firing patterns observed in vivo in the two regions.

Authors+Show Affiliations

Myme CI
Department of Biology, Volen Center for Complex Systems, Brandeis University, Waltham, Massachusetts 02454-9110, USA.
Sugino K
No affiliation info available
Turrigiano GG
No affiliation info available
Nelson SB
No affiliation info available

MeSH

AnimalsElectrophysiologyExcitatory Amino Acid AntagonistsExcitatory Postsynaptic PotentialsPatch-Clamp TechniquesPrefrontal CortexRatsRats, Long-EvansReceptors, AMPAReceptors, N-Methyl-D-AspartateVisual Cortex

Pub Type(s)

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

Language

eng

PubMed ID

12672778

Citation

Myme, Chaelon I O., et al. "The NMDA-to-AMPA Ratio at Synapses Onto Layer 2/3 Pyramidal Neurons Is Conserved Across Prefrontal and Visual Cortices." Journal of Neurophysiology, vol. 90, no. 2, 2003, pp. 771-9.
Myme CI, Sugino K, Turrigiano GG, et al. The NMDA-to-AMPA ratio at synapses onto layer 2/3 pyramidal neurons is conserved across prefrontal and visual cortices. J Neurophysiol. 2003;90(2):771-9.
Myme, C. I., Sugino, K., Turrigiano, G. G., & Nelson, S. B. (2003). The NMDA-to-AMPA ratio at synapses onto layer 2/3 pyramidal neurons is conserved across prefrontal and visual cortices. Journal of Neurophysiology, 90(2), 771-9.
Myme CI, et al. The NMDA-to-AMPA Ratio at Synapses Onto Layer 2/3 Pyramidal Neurons Is Conserved Across Prefrontal and Visual Cortices. J Neurophysiol. 2003;90(2):771-9. PubMed PMID: 12672778.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The NMDA-to-AMPA ratio at synapses onto layer 2/3 pyramidal neurons is conserved across prefrontal and visual cortices. AU - Myme,Chaelon I O, AU - Sugino,Ken, AU - Turrigiano,Gina G, AU - Nelson,Sacha B, Y1 - 2003/04/02/ PY - 2003/4/4/pubmed PY - 2003/10/2/medline PY - 2003/4/4/entrez SP - 771 EP - 9 JF - Journal of neurophysiology JO - J Neurophysiol VL - 90 IS - 2 N2 - To better understand regulation of N-methyl-d-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor complements across the cortex, and to investigate NMDA receptor (NMDAR)-based models of persistent activity, we compared NMDA/AMPA ratios in prefrontal (PFC) and visual cortex (VC) in rat. Whole cell voltage-clamp responses were recorded in brain slices from layer 2/3 pyramidal cells of the medial PFC and VC of rats aged p16-p21. Mixed miniature excitatory postsynaptic currents (mEPSCs) having AMPA receptor (AMPAR)- and NMDAR-mediated components were isolated in nominally 0 Mg2+ ACSF. Averaged mEPSCs were well-fit by double exponentials. No significant differences in the NMDA/AMPA ratio (PFC: 27 +/- 1%; VC: 28 +/- 3%), peak mEPSC amplitude (PFC: 19.1 +/- 1 pA; VC: 17.5 +/- 0.7 pA), NMDAR decay kinetics (PFC: 69 +/- 8 ms; VC: 67 +/- 6 ms), or degree of correlation between NMDAR- and AMPAR-mediated mEPSC components were found between the areas (PFC: n = 27; VC: n = 28). Recordings from older rats (p26-29) also showed no differences. EPSCs were evoked extracellularly in 2 mM Mg2+ at depolarized potentials; although the average NMDA/AMPA ratio was larger than that observed for mEPSCs, the ratio was similar in the two regions. In nominally 0 Mg2+ and in the presence of CNQX, spontaneous activation of NMDAR increased recording noise and produced a small tonic depolarization which was similar in both areas. We conclude that this basic property of excitatory transmission is conserved across PFC and VC synapses and is therefore unlikely to contribute to differences in firing patterns observed in vivo in the two regions. SN - 0022-3077 UR - https://www.unboundmedicine.com/medline/citation/12672778/The_NMDA_to_AMPA_ratio_at_synapses_onto_layer_2/3_pyramidal_neurons_is_conserved_across_prefrontal_and_visual_cortices_ DB - PRIME DP - Unbound Medicine ER -