title: Essential role of postsynaptic NMDA receptors in developmental refinement of excitatory synapses.
abstract: Neurons in the brains of newborns are usually connected with many other neurons through weak synapses. This early pattern of connectivity is refined through pruning of many immature connections and strengthening of the remaining ones. NMDA receptors (NMDARs) are essential for the development of excitatory synapses, but their role in synaptic refinement is controversial. Although chronic application of blockers or global knockdown of NMDARs disrupts developmental refinement in many parts of the brain, the ubiquitous presence of NMDARs makes it difficult to dissociate direct effects from indirect ones. We addressed this question in the thalamus by using genetic mosaic deletion of NMDARs. We demonstrate that pruning and strengthening of immature synapses are blocked in neurons without NMDARs, but occur normally in neighboring neurons with NMDARs. Our data support a model in which activation of NMDARs in postsynaptic neurons initiates synaptic refinement.
authors.affiliation: The Jackson Laboratory, Bar Harbor, ME 04609, USA. zhongwei.zhang@jax.org
authors.forename: Zhong-wei
authors.initials: ZW
authors.lastname: Zhang
authors.forename: Matthew
authors.initials: M
authors.lastname: Peterson
authors.forename: Hong
authors.initials: H
authors.lastname: Liu
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002352:Carrier Proteins / Q000235:genetics; D055724:Electrophysiological Phenomena; D019706:Excitatory Postsynaptic Potentials; D051379:Mice; D018345:Mice, Knockout; D008959:Models, Neurological; D009030:Mosaicism; D009419:Nerve Tissue Proteins / Q000172:deficiency / Q000235:genetics; D057907:Post-Synaptic Density / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D013569:Synapses / Q000378:metabolism*; D009435:Synaptic Transmission; D013787:Thalamic Nuclei / Q000254:growth & development / Q000378:metabolism; D013788:Thalamus / Q000254:growth & development* / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; C121673:Gprin1 protein, mouse; D009419:Nerve Tissue Proteins; D016194:Receptors, N-Methyl-D-Aspartate