歯の神経の新たな役割を解明(Tooth Nerves That Serve as Pain Detectors Have Another Purpose: Tooth Protectors)

2025-07-25 ミシガン大学

<関連情報>

• https://news.umich.edu/ouch-tooth-nerves-that-serve-as-pain-detectors-have-another-purpose-tooth-protectors/
• https://www.cell.com/cell-reports/fulltext/S2211-1247(25)00788-0

歯内機械痛覚受容器は歯の損傷を防ぐ見張り役として働く Intradental mechano-nociceptors serve as sentinels that prevent tooth damage

Elizabeth A. Ronan ∙ Akash R. Gandhi ∙ Karin H. Uchima Koecklin ∙ … ∙ Bing Ye^, ∙ Peng Li ∙ Joshua J. Emrick
Cell Reports  Published:July 16, 2025
DOI:https://doi.org/10.1016/j.celrep.2025.116017

Graphical abstract

Highlights

• In vivo calcium imaging enables real-time monitoring of intradental neurons
• Intradental neurons are mechano-nociceptors that respond to superficial tooth damage
• Activation of intradental neurons elicits pain identified via LabGym analysis
• Activation of intradental neurons triggers a protective jaw-opening reflex

Summary

The trigeminal sensory neurons that innervate the tooth’s vital interior—intradental neurons—are expected to drive severe pain, yet their contribution to healthy tooth sensation has not been explored. Here, we uncover a role for myelinated high-threshold mechano-nociceptors (intradental HTMRs) in tooth protection using in vivo Ca²⁺ imaging, opto-/chemogenetics, and the AI-driven behavioral analysis tool LabGym. Intradental HTMRs innervate the inner dentin through overlapping receptive fields and respond as the external structures of the tooth are damaged in the absence of either PIEZO2 or Na_v1.8. Whereas chemogenetic activation of intradental HTMRs results in a pain phenotype marked by facial and postural changes, their transient optogenetic activation triggers a rapid, jaw-opening reflex via contraction of the digastric muscle. Our work indicates that intradental HTMRs not only trigger pain but also protect the teeth by initiating a reflexive movement of the jaws when the teeth experience damage during chewing.