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Updated: Dec 27, 2025
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Examining Monosynaptic Connections in Drosophila Using Tetrodotoxin Resistant Sodium Channels
Published on: February 14, 2018
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TTX-Resistant Sodium Channels Functionally Separate Silent From Polymodal C-nociceptors.
Robin Jonas1, Vincenzo Prato2, Stefan G Lechner2
1Department of Experimental Pain Research, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany.
Frontiers in Cellular Neuroscience
|March 3, 2020
Summary
Silent nociceptors exhibit tetrodotoxin-resistance (TTX-r) and pronounced activity-dependent slowing. These axonal properties, including increased calcium transients, distinguish them from other nociceptor classes.
Area of Science:
- Neuroscience
- Pain research
- Ion channel physiology
Background:
- Activity-dependent slowing of conduction characterizes mechano-insensitive, "silent" nociceptors.
- This slowing may be linked to high expression of tetrodotoxin-resistant sodium channels (NaV1.8).
Purpose of the Study:
- To investigate nociceptor-class specific differences in action potential characteristics.
- To explore the relationship between tetrodotoxin-resistance (TTX-r) and axonal properties in silent nociceptors.
Main Methods:
- In vitro calcium imaging in single porcine nerve growth factor (NGF)-responsive neurites.
- In vivo extracellular recordings in functionally identified porcine silent nociceptors.
- In vitro patch-clamp recordings from murine silent nociceptors (CHRNA3 expression).
Main Results:
- Porcine TTX-r neurites showed over twice the calcium transients per action potential compared to TTX-sensitive (TTX-s) neurites.
- Porcine silent nociceptors were TTX-r and displayed pronounced activity-dependent slowing, unlike TTX-s polymodal nociceptors.
- Murine silent nociceptors exhibited longer action potential duration and higher peak amplitudes than putative polymodal nociceptors.
Conclusions:
- Axonal properties, including TTX-resistance and calcium handling, differ between nociceptor classes.
- Findings suggest silent nociceptors possess distinct axonal characteristics beyond their receptive fields.
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