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Updated: Aug 30, 2026

Temporomandibular Joint Pain Measurement by Bite Force and Von Frey Filament Assays in Mice
Published on: September 13, 2024
Subtypes of nociceptive units in the rat temporomandibular joint
Yoshinari Takeuchi1, Kazuo Toda
1Maxillofacial Surgery, Maxillofacial Reconstruction, Division of Maxillofacial and Neck Reconstruction, Graduate School, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo 113-8549, Japan.
Abstract:
Response properties of nociceptors in the rat's temporomandibular joint (TMJ) were investigated using an in vitro TMJ-nerve preparation. Recordings were obtained from 33 nociceptive units that responded to mechanical, chemical, and/or thermal stimuli. According to both characteristics of nociceptors and afferent fibers, nociceptive units in the TMJ area were classified into the following four subtypes: Adelta-high-threshold mechanonociceptor (HTM) (12.1%), Adelta-polymodal nociceptor (POLY) (36.4%), C-HTM (12.1%), and C-POLY (39.4%). The mean mechanical threshold of the Adelta units was significantly lower than that of the C units. Bradykinin increased the discharge of Adelta- and C-POLY units. No significant differences of thermal thresholds between Adelta and C units were found. The percentage of Adelta units was 47.2% and of C units was 52.8%, respectively. In the TMJ area, POLY units were predominant (75.8%), suggesting that inflammatory reactions can easily evoke pain sensation.

