title: Nitric oxide mediates local activity-dependent excitatory synapse development.
abstract: Learning related paradigms play an important role in shaping the development and specificity of synaptic networks, notably by regulating mechanisms of spine growth and pruning. The molecular events underlying these synaptic rearrangements remain poorly understood. Here we identify NO signaling as a key mediator of activity-dependent excitatory synapse development. We find that chronic blockade of NO production in vitro and in vivo interferes with the development of hippocampal and cortical excitatory spine synapses. The effect results from a selective loss of activity-mediated spine growth mechanisms and is associated with morphological and functional alterations of remaining synapses. These effects of NO are mediated by a cGMP cascade and can be reproduced or prevented by postsynaptic expression of vasodilator-stimulated phosphoprotein phospho-mimetic or phospho-resistant mutants. In vivo analyses show that absence of NO prevents the increase in excitatory synapse density induced by environmental enrichment and interferes with the formation of local clusters of excitatory synapses. We conclude that NO plays an important role in regulating the development of excitatory synapses by promoting local activity-dependent spine-growth mechanisms.
authors.affiliation: Department of Basic Neuroscience, Geneva Medical Center, University of Geneva, 1211 Geneva 4, Switzerland.
authors.forename: Irina
authors.initials: I
authors.lastname: Nikonenko
authors.forename: Alexander
authors.initials: A
authors.lastname: Nikonenko
authors.forename: Pablo
authors.initials: P
authors.lastname: Mendez
authors.forename: Tatyana V
authors.initials: TV
authors.lastname: Michurina
authors.forename: Grigori
authors.initials: G
authors.lastname: Enikolopov
authors.forename: Dominique
authors.initials: D
authors.lastname: Muller
mesh_terms: D000818:Animals; D015815:Cell Adhesion Molecules / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D005071:Evoked Potentials / Q000502:physiology; D005838:Genotype; D006624:Hippocampus / Q000254:growth & development*; D007858:Learning / Q000502:physiology*; D051379:Mice; D008840:Microfilament Proteins / Q000378:metabolism; D008854:Microscopy, Electron; D009415:Nerve Net / Q000254:growth & development*; D009473:Neuronal Plasticity / Q000502:physiology*; D009569:Nitric Oxide / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D016133:Polymerase Chain Reaction; D051381:Rats; D015398:Signal Transduction / Q000502:physiology*; D013569:Synapses / Q000502:physiology* / Q000648:ultrastructure; D000098662:Vasodilator-Stimulated Phosphoprotein
chemical_list: D015815:Cell Adhesion Molecules; D017931:DNA Primers; D008840:Microfilament Proteins; D010750:Phosphoproteins; D000098662:Vasodilator-Stimulated Phosphoprotein; D009569:Nitric Oxide; D006152:Cyclic GMP
keywords: VASP; dendritic spines; spinogenesis; synaptic plasticity