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Quantifying Synapses: an Immunocytochemistry-based Assay to Quantify Synapse Number
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Glial amplification of synaptic signals
Kaoru Beppu1, Naoko Kubo1, Ko Matsui1,2
1Division of Interdisciplinary Medical Science, Center for Neuroscience, Graduate School of Medicine, Tohoku University, Sendai, 980-8575, Japan.
The Journal of Physiology
|February 2, 2021
Summary
Cerebellar Bergmann glial cells release glutamate, contributing to synaptic currents and amplifying brain signal processing. This glial glutamate release influences excitatory information processing, challenging the sole neuronal origin of postsynaptic signals.
Area of Science:
- Neuroscience
- Cellular Biology
- Glial Cell Function
Background:
- Neuronal and glial circuits exhibit complex signal cross-talk.
- Astrocytes, including Bergmann glial cells (BGs) in the cerebellum, can release transmitters.
- The role of glial-released transmitters in synaptic current generation is under investigation.
Purpose of the Study:
- To investigate the mechanism and influence of physiological interactions between neurons and glia in the cerebellum.
- To determine if Bergmann glial cells contribute to synaptic current.
- To explore the role of glial glutamate release in information processing.
Main Methods:
- Preparation of acute cerebellar slices from mice.
- Whole-cell patch clamp recordings from Purkinje cells and Bergmann glial cells.
- Application of glutamate, d-aspartate (d-Asp), and use of optogenetic tools (archaetrhodopsin-T, channelrhodopsin-2).
- Pharmacological blockade of volume-regulated anion channels.
Main Results:
- Bergmann glial cells release glutamate in response to glutamate and d-Asp.
- Glutamate release from BGs is mediated by volume-regulated anion channels.
- Optogenetic manipulation of BGs altered glial glutamate release and synaptic responses.
- A portion of the postsynaptic current was mediated by glutamate released from Bergmann glial cells.
Conclusions:
- Bergmann glial cells release glutamate, acting as an amplifier of excitatory information processing.
- Glial-derived glutamate contributes to synaptic currents, expanding the understanding of brain signal transmission.
- Modulating Bergmann glial cell activity has direct consequences on brain information processing.
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