Astrocyte calcium signalling orchestrates neuronal synchronization in organotypic hippocampal slices.
Astrocytes are thought to detect neuronal activity in the form of intracellular calcium elevations; thereby, astrocytes can regulate neuronal excitability and synaptic transmission. Little is known, however, about how the astrocyte calcium signal regulates the activity of neuronal populations. In this study, we addressed this issue using functional multineuron calcium imaging in hippocampal slice cultures. Under normal conditions, CA3 neuronal networks exhibited temporally correlated activity patterns, occasionally generating large synchronization among a subset of cells. The synchronized neuronal activity was correlated with astrocyte calcium events. Calcium buffering by an intracellular injection of a calcium chelator into multiple astrocytes reduced the synaptic strength of unitary transmission between pairs of surrounding pyramidal cells and caused desynchronization of the neuronal networks. Uncaging the calcium in the astrocytes increased the frequency of neuronal synchronization. These data suggest an essential role of the astrocyte calcium signal in the maintenance of basal neuronal function at the circuit level.
Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan t.sasaki.0224@gmail.com.
Takuya
T
Sasaki
Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan.
Tomoe
T
Ishikawa
Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan.
Reimi
R
Abe
Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan.
Ryota
R
Nakayama
Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan.
Akiko
A
Asada
Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan.
Norio
N
Matsuki
Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan Center for Information and Neural Networks, Suita City, Osaka, Japan.
Yuji
Y
Ikegaya
D000818:Animals; D001253:Astrocytes / Q000378:metabolism* / Q000502:physiology; D056654:CA3 Region, Hippocampal / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D020013:Calcium Signaling; D017966:Pyramidal Cells / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D009435:Synaptic Transmission