Dynamic inhibition of excitatory synaptic transmission by astrocyte-derived ATP in hippocampal cultures

Schuichi Koizumi, Kayoko Fujishita, Makoto Tsuda, Yukari Shigemoto-Mogami, Kazuhide Inoue

Research output: Contribution to journalArticlepeer-review

189 Citations (Scopus)

Abstract

Originally ascribed passive roles in the CNS, astrocytes are now known to have an active role in the regulation of synaptic transmission. Neuronal activity can evoke Ca2+ transients in astrocytes, and Ca 2+ transients in astrocytes can evoke changes in neuronal activity. The excitatory neurotransmitter glutamate has been shown to mediate such bidirectional communication between astrocytes and neurons. We demonstrate here that ATP, a primary mediator of intercellular Ca2+ signaling among astrocytes, also mediates intercellular signaling between astrocytes and neurons in hippocampal cultures. Mechanical stimulation of astrocytes evoked Ca2+ waves mediated by the release of ATP and the activation of P2 receptors. Mechanically evoked Ca2+ waves led to decreased excitatory glutamatergic synaptic transmission in an ATP-dependent manner. Exogenous application of ATP does not affect postsynaptic glutamatergic responses but decreased presynaptic exocytotic events. Finally, we show that astrocytes exhibit spontaneous Ca2+ waves mediated by extracellular ATP and that inhibition of these Ca2+ responses enhanced excitatory glutamatergic transmission. We therefore conclude that ATP released from astrocytes exerts tonic and activity-dependent down-regulation of synaptic transmission via presynaptic mechanisms.

Original languageEnglish
Pages (from-to)11023-11028
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume100
Issue number19
DOIs
Publication statusPublished - Sep 16 2003

All Science Journal Classification (ASJC) codes

  • General

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