Roles of mGluR5 in synaptic function and plasticity of the mouse thalamocortical pathway.

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Type
Article: article from journal or magazin.
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Publications
Institution
Title
Roles of mGluR5 in synaptic function and plasticity of the mouse thalamocortical pathway.
Journal
European Journal of Neuroscience
Author(s)
She W.C., Quairiaux C., Albright M.J., Wang Y.C., Sanchez D.E., Chang P.S., Welker E., Lu H.C.
ISSN
1460-9568[electronic]
Publication state
Published
Issued date
04/2009
Peer-reviewed
Oui
Volume
29
Number
7
Pages
1379-1396
Language
english
Abstract
The group I metabotropic glutamate receptor 5 (mGluR5) has been implicated in the development of cortical sensory maps. However, its precise roles in the synaptic function and plasticity of thalamocortical (TC) connections remain unknown. Here we first show that in mGluR5 knockout (KO) mice bred onto a C57BL6 background cytoarchitectonic differentiation into barrels is missing, but the representations for large whiskers are identifiable as clusters of TC afferents. The altered dendritic morphology of cortical layer IV spiny stellate neurons in mGluR5 KO mice implicates a role for mGluR5 in the dendritic morphogenesis of excitatory neurons. Next, in vivo single-unit recordings of whisker-evoked activity in mGluR5 KO adults demonstrated a preserved topographical organization of the whisker representation, but a significantly diminished temporal discrimination of center to surround whiskers in the responses of individual neurons. To evaluate synaptic function at TC synapses in mGluR5 KO mice, whole-cell voltage-clamp recording was conducted in acute TC brain slices prepared from postnatal day 4-11 mice. At mGluR5 KO TC synapses, N-methyl-D-aspartate (NMDA) currents decayed faster and synaptic strength was more easily reduced, but more difficult to strengthen by Hebbian-type pairing protocols, despite a normal developmental increase in alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR)-mediated currents and presynaptic function. We have therefore demonstrated that mGluR5 is required for synaptic function/plasticity at TC synapses as barrels are forming, and we propose that these functional alterations at the TC synapse are the basis of the abnormal anatomical and functional development of the somatosensory cortex in the mGluR5 KO mouse.
Keywords
barrels , cortical maps , mGluR , somatosensory cortex , thalamocortical synapses
Pubmed
Web of science
Create date
29/06/2009 12:42
Last modification date
20/08/2019 13:09
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