title: Subcellular location of astrocytic calcium stores favors extrasynaptic neuron-astrocyte communication.
abstract: Neuron-astrocyte interactions are important for brain computations and synaptic plasticity. Perisynaptic astrocytic processes (PAPs) contain a high density of transporters that are responsible for neurotransmitter clearance. Metabotropic glutamate receptors are thought to trigger Ca(2+) release from Ca(2+) stores in PAPs in response to synaptic activity. Our ultrastructural study revealed that PAPs are actually devoid of Ca(2+) stores and have a high surface-to-volume ratio favorable for uptake. Astrocytic processes containing Ca(2+) stores were located further away from the synapses and could therefore respond to changes in ambient glutamate. Thus, the anatomic data do not support communication involving Ca(2+) stores in tripartite synapses, but rather point to extrasynaptic communication.
authors.affiliation: RIKEN Brain Science Institute, Wako, Saitama, 351-0198, Japan.
authors.forename: Ilya
authors.initials: I
authors.lastname: Patrushev
authors.forename: Nikolay
authors.initials: N
authors.lastname: Gavrilov
authors.forename: Vadim
authors.initials: V
authors.lastname: Turlapov
authors.forename: Alexey
authors.initials: A
authors.lastname: Semyanov
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D002118:Calcium / Q000378:metabolism*; D002450:Cell Communication; D018698:Glutamic Acid / Q000494:pharmacology; D006624:Hippocampus / Q000378:metabolism; D008297:Male; D008854:Microscopy, Electron; D009010:Monte Carlo Method; D009474:Neurons / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D018094:Receptors, Metabotropic Glutamate / Q000378:metabolism; D013569:Synapses / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D018094:Receptors, Metabotropic Glutamate; D018698:Glutamic Acid; D002118:Calcium
keywords: Astrocyte; Neuron–glia interaction; Perisynaptic processes; Postsynaptic density