title: Direct imaging of lateral movements of AMPA receptors inside synapses.
abstract: Trafficking of AMPA receptors in and out of synapses is crucial for synaptic plasticity. Previous studies have focused on the role of endo/exocytosis processes or that of lateral diffusion of extra-synaptic receptors. We have now directly imaged AMPAR movements inside and outside synapses of live neurons using single-molecule fluorescence microscopy. Inside individual synapses, we found immobile and mobile receptors, which display restricted diffusion. Extra-synaptic receptors display free diffusion. Receptors could also exchange between these membrane compartments through lateral diffusion. Glutamate application increased both receptor mobility inside synapses and the fraction of mobile receptors present in a juxtasynaptic region. Block of inhibitory transmission to favor excitatory synaptic activity induced a transient increase in the fraction of mobile receptors and a decrease in the proportion of juxtasynaptic receptors. Altogether, our data show that rapid exchange of receptors between a synaptic and extra-synaptic localization occurs through regulation of receptor diffusion inside synapses.
authors.affiliation: Centre de Physique Moléculaire Optique et Hertzienne - CNRS UMR 5798 et Université Bordeaux 1, 351 Cours de la Libération, 33405 Talence, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Tardin
authors.forename: Laurent
authors.initials: L
authors.lastname: Cognet
authors.forename: Cécile
authors.initials: C
authors.lastname: Bats
authors.forename: Brahim
authors.initials: B
authors.lastname: Lounis
authors.forename: Daniel
authors.initials: D
authors.lastname: Choquet
mesh_terms: D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D002478:Cells, Cultured; D004058:Diffusion; D004622:Embryo, Mammalian; D051273:Glucose Transporter Type 2; D018698:Glutamic Acid / Q000494:pharmacology; D006624:Hippocampus / Q000502:physiology; D008856:Microscopy, Fluorescence; D009004:Monosaccharide Transport Proteins / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D009473:Neuronal Plasticity; D009474:Neurons / Q000166:cytology; D051381:Rats; D013569:Synapses / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D013779:Tetrodotoxin / Q000494:pharmacology
chemical_list: D051273:Glucose Transporter Type 2; D009004:Monosaccharide Transport Proteins; D018698:Glutamic Acid; D013779:Tetrodotoxin; D001640:Bicuculline