Related Experiment Video
Updated: May 21, 2025
16:38
Dual Electrophysiological Recordings of Synaptically-evoked Astroglial and Neuronal Responses in Acute Hippocampal Slices
Published on: November 26, 2012
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Astrocyte-induced firing in primary afferent axons
Fanny Gaudel1,2, Julia Giraud1, Philippe Morquette1,3
1Département de Neurosciences, Université de Montréal, Montréal, QC, Canada.
Iscience
|March 19, 2025
Summary
Astrocytes, via S100β, reduce extracellular calcium, enhancing neuronal excitability and ectopic firing in jaw muscles. This neuron-astrocyte interaction may drive hyperexcitability in various conditions.
Area of Science:
- Neuroscience
- Cellular Biology
- Muscle Physiology
Background:
- Jaw muscle pain involves hyperexcitability of primary afferents in the mesencephalic trigeminal nucleus (NVmes).
- This hyperexcitability is linked to subthreshold membrane oscillations (SMOs) dependent on persistent sodium current (INaP) and sensitive to extracellular calcium (Ca2+).
Purpose of the Study:
- To investigate the role of the astrocytic protein S100β in NVmes neuron hyperexcitability.
- To determine the specific axonal location where ectopic discharges originate.
Main Methods:
- Whole-cell patch-clamp recordings in mouse brain slices.
- Modeling of acid-induced chronic myalgia.
Main Results:
- Astrocytes, through S100β, decrease focal extracellular Ca2+ ([Ca2+]e) levels along NVmes neuron axons.
- This reduction enhances the amplitude of NaV1.6-dependent SMOs.
- Enhanced SMOs lead to ectopic action potential firing, indicating the axon as the origin of abnormal discharges.
Conclusions:
- Astrocytes actively regulate neuronal excitability by modulating extracellular ion concentrations.
- The S100β-mediated neuron-astrocyte interaction is a critical mechanism contributing to NVmes afferent hyperexcitability.
- This interaction presents a potential therapeutic target for conditions involving neuronal hyperexcitability.
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