Related Experiment Video
Updated: Jun 20, 2026
In Vivo Functional Assessment of Rat Masseter Muscle Following Surgical Creation of a Volumetric Muscle Loss (VML) Injury
Published on: November 15, 2024
Functional changes of temporomandibular joint mechanoreceptors induced by reduced masseter muscle activity in growing
Takayoshi Ishida1, Tadachika Yabushita, Kunimichi Soma
1Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan. takaorts@tmd.ac.jp
Objective:
To determine the influence of masseter muscle activity during growth on the functional characteristics of temporomandibular joint (TMJ) mechanoreceptors.
Materials And Methods:
Sixty-six 3-week-old male Wistar rats were divided into an experimental group, in which the masseter muscles were bilaterally resected at 3 weeks of age, and a control group. Single-unit activities of the TMJ mechanoreceptors were evoked by indirect stimulation of passive jaw movement. Electrophysiologic recordings of TMJ units were made at 5, 7, and 9 weeks of age.
Results:
During this period, the firing threshold of the TMJ units was significantly lower and the maximum instantaneous frequency of the TMJ units was significantly higher in the experimental group than in the control group.
Conclusion:
Reduced masseter activity during the growth period alters the response properties of TMJ mechanoreceptors.
