Share Page:

Volume 19 , Issue 2
Spring 2005

Pages 159–167

Bite Force Measurement in Awake Rats: A Behavioral Model for Persistent Orofacial Muscle Pain and Hyperalgesia

Jin Y. Ro, PhD

PMID: 15895839

Aims: To test the hypotheses that masseteric inflammation produces a reduction of mean bite force and success rates and that classical anti-inflammatory agents prevent inflammation-induced changes in bite force. Methods: Rats were initially trained to produce a bite force greater than 400 g. Once the rats attained above 70% of successful responses in a 10-minute test period, the bite force required for reinforcement was increased gradually to the target force of 1.3 kg. Seven trained rats received bilateral masseteric injections of complete Freund’s adjuvant (CFA; 50 µL in isotonic saline). The mean number of attempted bites, the percentage of correct responses, and the bite force measured before and 1, 2, 3, 7, 10, and 14 days following the CFA injection were compared. Five additional trained rats were injected with the same volume of vehicle control. Other rats (n = 10) were treated with anti-inflammatory agents before and after the CFA injection. Results: Intramuscular CFA, but not the vehicle, produced a significant reduction of mean bite force and success rate at days 1, 2, and 3. Bite force and success rate gradually increased; they returned to baseline by 14 days. The CFA-mediated reduction of bite force and success rate was prevented in rats treated with anti-inflammatory agents administered intraperitoneally (dexamethasone, n = 5, or indomethacin, n = 5, 4 mg/kg). Conclusion: These results provide further evidence that bite force measurements in awake rats can be a useful method for the study of inflammatory muscle hyperalgesia. J Orofac Pain 2005;19:159–167

Full Text PDF File | Order Article


Get Adobe Reader
Adobe Acrobat Reader is required to view PDF files. This is a free program available from the Adobe web site.
Follow the download directions on the Adobe web site to get your copy of Adobe Acrobat Reader.


© 2017 Quintessence Publishing Co, Inc

Current Issue
Ahead of Print
Author Guidelines
Accepted Manuscripts
Submission Form
Quintessence Home
Terms of Use
Privacy Policy
About Us
Contact Us