title: Structural and functional plasticity of astrocyte processes and dendritic spine interactions.
abstract: Experience-dependent plasticity of synaptic transmission, which represents the cellular basis of learning, is accompanied by morphological changes in dendritic spines. Astrocytic processes are intimately associated with synapses, structurally enwrapping and functionally interacting with dendritic spines and synaptic terminals by responding to neurotransmitters and by releasing gliotransmitters that regulate synaptic function. While studies on structural synaptic plasticity have focused on neuronal elements, the structural-functional plasticity of astrocyte-neuron relationships remains poorly known. Here we show that stimuli inducing hippocampal synaptic LTP enhance the motility of synapse-associated astrocytic processes. This motility increase is relatively rapid, starting <5 min after the stimulus, and reaching a maximum in 20-30 min (t(1/2) = 10.7 min). It depends on presynaptic activity and requires G-protein-mediated Ca(2+) elevations in astrocytes. The structural remodeling is accompanied by changes in the ability of astrocytes to regulate synaptic transmission. Sensory stimuli that increase astrocyte Ca(2+) also induce similar plasticity in mouse somatosensory cortex in vivo. Therefore, structural relationships between astrocytic processes and dendritic spines undergo activity-dependent changes with metaplasticity consequences on synaptic regulation. These results reveal novel forms of synaptic plasticity based on structural-functional changes of astrocyte-neuron interactions.
authors.affiliation: Instituto Cajal, CSIC, 28002 Madrid, Spain, Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg (ZMNH), University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany.
authors.forename: Alberto
authors.initials: A
authors.lastname: Perez-Alvarez
authors.affiliation: Instituto Cajal, CSIC, 28002 Madrid, Spain.
authors.forename: Marta
authors.identifier: http://orcid.org/0000-0003-2097-4788
authors.initials: M
authors.lastname: Navarrete
authors.affiliation: Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455.
authors.forename: Ana
authors.initials: A
authors.lastname: Covelo
authors.affiliation: Laboratory of Neurophysiology and Synaptic Plasticity, Albacete Science and Technology Park (PCYTA), Institute for Research in Neurological Disabilities (IDINE), University of Castilla-La Mancha, 02006 Albacete, Spain, and.
authors.forename: Eduardo D
authors.initials: ED
authors.lastname: Martin
authors.affiliation: Instituto Cajal, CSIC, 28002 Madrid, Spain and Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455.
authors.forename: Alfonso
authors.initials: A
authors.lastname: Araque
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D049229:Dendritic Spines / Q000502:physiology*; D005260:Female; D006624:Hippocampus / Q000502:physiology; D017774:Long-Term Potentiation / Q000187:drug effects / Q000502:physiology; D008297:Male; D051379:Mice; D009473:Neuronal Plasticity / Q000502:physiology*; D013003:Somatosensory Cortex / Q000502:physiology; D009435:Synaptic Transmission / Q000502:physiology
chemical_list: D002118:Calcium
keywords: astrocyte; astrocyte–neuron interactions; dendritic spines; remodeling