Effect of transgenic overexpression of NR2B on NMDA receptor function and synaptic plasticity in visual cortex

Benjamin D. Philpot, Michael P. Weisberg, Margarita S. Ramos, Nathaniel B. Sawtell, Ya Ping Tang, Joseph Zhuo Tsien, Mark F. Bear

Research output: Contribution to journalArticle

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Abstract

The NMDA receptor (NMDAR) is a heteromer comprised of NR1 and NR2 subunits. Mice that overexpress the NR2B subunit exhibit enhanced hippocampal LTP, prolonged NMDAR currents, and improved memory (Tang et al., 1999). In the current study, we explored visual cortex plasticity and NMDAR function in NR2B overexpressing transgenic mice. Unlike the hippocampus, in vitro synaptic plasticity of the visual cortex was unaltered by NR2B overexpression. Consistent with the plasticity findings, NMDAR excitatory postsynaptic current (EPSC) durations from layer 2/3 pyramidal cells were similar in wild-type (wt) and transgenic (tg) mice. Furthermore, temporal summation of NMDAR EPSCs to 10, 20, and 40 Hz stimulation did not differ between cells from wt and tg mice. Finally, although in situ studies clearly demonstrate overexpression of NR2B mRNA in visual cortex, we failed to observe a significant elevation in the synaptic expression of NR2B protein. We conclude that the synaptic ratio of NR2B over NR2A in the NMDA receptor complex in the visual cortex is not significantly influenced by the transgene overexpression. These data suggest that mRNA availability is not a limiting factor for the synthesis of NR2B protein in the visual cortex, and support the hypothesis that levels of NR2A, rather than NR2B, normally determine the subunit composition of NMDARs in visual cortex.

Original languageEnglish (US)
Pages (from-to)762-770
Number of pages9
JournalNeuropharmacology
Volume41
Issue number6
DOIs
StatePublished - Oct 25 2001

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Neuronal Plasticity
Visual Cortex
N-Methyl-D-Aspartate Receptors
Transgenic Mice
Messenger RNA
Pyramidal Cells
Excitatory Postsynaptic Potentials
Transgenes
NR2B NMDA receptor
Hippocampus
Proteins

Keywords

  • Cortical plasticity
  • Critical period
  • LTP
  • Metaplasticity
  • NMDA receptor
  • NR2B

ASJC Scopus subject areas

  • Pharmacology
  • Cellular and Molecular Neuroscience

Cite this

Effect of transgenic overexpression of NR2B on NMDA receptor function and synaptic plasticity in visual cortex. / Philpot, Benjamin D.; Weisberg, Michael P.; Ramos, Margarita S.; Sawtell, Nathaniel B.; Tang, Ya Ping; Tsien, Joseph Zhuo; Bear, Mark F.

In: Neuropharmacology, Vol. 41, No. 6, 25.10.2001, p. 762-770.

Research output: Contribution to journalArticle

Philpot, Benjamin D. ; Weisberg, Michael P. ; Ramos, Margarita S. ; Sawtell, Nathaniel B. ; Tang, Ya Ping ; Tsien, Joseph Zhuo ; Bear, Mark F. / Effect of transgenic overexpression of NR2B on NMDA receptor function and synaptic plasticity in visual cortex. In: Neuropharmacology. 2001 ; Vol. 41, No. 6. pp. 762-770.
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