Astrocyte-induced firing in primary afferent axons
Summary: The large-caliber primary afferents innervating the spindles of the jaw-closing muscles have their cell bodies located centrally in the mesencephalic trigeminal nucleus (NVmes). We have shown, in an acid-induced jaw muscle chronic myalgia model, that these afferents exhibit increased excita...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-03-01
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| Series: | iScience |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2589004225002664 |
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| Summary: | Summary: The large-caliber primary afferents innervating the spindles of the jaw-closing muscles have their cell bodies located centrally in the mesencephalic trigeminal nucleus (NVmes). We have shown, in an acid-induced jaw muscle chronic myalgia model, that these afferents exhibit increased excitability and ectopic discharges that emerge from subthreshold membrane oscillations (SMOs) supported by a persistent sodium current (INaP) exquisitely sensitive to extracellular Ca2+-decreases. Here, we explore if the Ca2+-binding astrocytic protein, S100β, contributes to this hyperexcitability emergence and aim to localize the site where ectopic discharge arises using whole-cell patch-clamp recordings on mice brain slices. We found that astrocytes, by lowering [Ca2+]e at focal points along the axons of NVmes neurons through S100β, enhance the amplitude of the NaV1.6-dependent SMOs, leading to ectopic firing. These findings suggest a crucial role for astrocytes in excitability regulation and raise questions about this neuron-astrocyte interaction as a key contributor to hyperexcitability in several pathologies. |
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| ISSN: | 2589-0042 |