• DOI:10.1124/JPET.103.050781
• Corpus ID: 10641822

Allodynia and Hyperalgesia in Adjuvant-Induced Arthritic Rats: Time Course of Progression and Efficacy of Analgesics

@article{Nagakura2003AllodyniaAH,
  title={Allodynia and Hyperalgesia in Adjuvant-Induced Arthritic Rats: Time Course of Progression and Efficacy of Analgesics},
  author={Yukinori Nagakura and Masamichi Okada and Atsuyuki Kohara and Tetsuo Kiso and Takashi Toya and Akihiko Iwai and Fumikazu Wanibuchi and Tokio Yamaguchi},
  journal={Journal of Pharmacology and Experimental Therapeutics},
  year={2003},
  volume={306},
  pages={490 - 497}
}

• Y. Nagakura, M. Okada, +5 authors Tokio Yamaguchi
• Published 1 August 2003
• Biology
• Journal of Pharmacology and Experimental Therapeutics

The complete Freund's adjuvant (CFA)-induced arthritic rat model has extensively served as a laboratory model in the study of arthritic pain. However, the time courses of allodynia and hyperalgesia and the efficacies of different analgesics have not fully been analyzed in this model. Mechanical allodynia, thermal and joint hyperalgesia, and other disease development parameters (body weight, mobility, paw volume, and joint stiffness) were measured on postinoculation days (PIDs) 0 to 28 in rats. Acute analgesic efficacies of drugs were evaluated on PID 9 when degrees of allodynia, hyperalgesia, and joint stiffness in the ipsilateral paw reached almost the maximum, although those in the contralateral paw changed only slightly. In the ipsilateral paw, thermal hyperalgesia reached the maximum on PID 1, whereas mechanical allodynia and joint hyperalgesia progressively developed during the first 7 or 8 days, being tuned in to arthritis development. In the contralateral paw, thermal hyperalgesia never occurred, whereas mechanical allodynia and joint hyperalgesia developed after PID 11. Morphine and tramadol had full efficacies for all the pain parameters tested at sedation-inducing doses. Indomethacin and diclofenac significantly but partially improved thermal and joint hyperalgesia. Amitriptyline significantly reduced thermal and joint hyperalgesia only at sedation-inducing dose. Acetaminophen, carbamazepine, and gabapentin had, at the most, very small efficacies. In conclusion, the present study provided integrated information about the time course of pain and other disease development parameters in the CFA-induced arthritic rats, and clarified acute efficacies of different categories of analgesics for the allodynia and hyperalgesia.