Astrocytic Ca2+ signals are required for the functional integrity of tripartite synapses

Neuronal activity alters calcium ion (Ca2+) dynamics in astrocytes, but the physiologic relevance of these changes is controversial. To examine this issue further, we generated an inducible transgenic mouse model in which the expression of an inositol 1,4,5-trisphosphate absorbent, "IP3 sponge&...

Full description

Saved in:
Bibliographic Details
Published in:Molecular brain 2013-01, Vol.6 (1), p.6-6, Article 6
Main Authors: Tanaka, Mika, Shih, Pei-Yu, Gomi, Hiroshi, Yoshida, Takamasa, Nakai, Junichi, Ando, Reiko, Furuichi, Teiichi, Mikoshiba, Katsuhiko, Semyanov, Alexey, Itohara, Shigeyoshi
Format: Article
Language:English
Subjects:
Animals
Anxiety - pathology
Anxiety - physiopathology
Aspartate
Astrocyte
Astrocytes - drug effects
Astrocytes - metabolism
Behavior, Animal - drug effects
Brain
Calcium
Calcium - metabolism
Calcium Signaling - drug effects
Cameras
Experiments
Fear - drug effects
Genetic engineering
Glutamate
Glutamates - metabolism
Glutathione Transferase - metabolism
Inositol
Inositol 1,4,5-Trisphosphate - pharmacology
Memory - drug effects
Methyl aspartate
Mice
Mice, Transgenic
Models, Biological
Neuron-glia interaction
Neurophysiology
Rodents
Science
Synapse
Synapses - drug effects
Synapses - metabolism
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Neuronal activity alters calcium ion (Ca2+) dynamics in astrocytes, but the physiologic relevance of these changes is controversial. To examine this issue further, we generated an inducible transgenic mouse model in which the expression of an inositol 1,4,5-trisphosphate absorbent, "IP3 sponge", attenuates astrocytic Ca2+ signaling. Attenuated Ca2+ activity correlated with reduced astrocytic coverage of asymmetric synapses in the hippocampal CA1 region in these animals. The decreased astrocytic 'protection' of the synapses facilitated glutamate 'spillover', which was reflected by prolonged glutamate transporter currents in stratum radiatum astrocytes and enhanced N-methyl-D-aspartate receptor currents in CA1 pyramidal neurons in response to burst stimulation. These mice also exhibited behavioral impairments in spatial reference memory and remote contextual fear memory, in which hippocampal circuits are involved. Our findings suggest that IP3-mediated astrocytic Ca2+ signaling correlates with the formation of functional tripartite synapses in the hippocampus.
ISSN:1756-6606
1756-6606
DOI:10.1186/1756-6606-6-6