Assessment of intraoral mucosal pain induced by the application of capsaicin

作者：Terayama Ryuji^*; Maruhama Kotaro; Tsuchiya Hiroki; Mizutani Masahide; Iida Seiji; Sugimoto Tomosada

来源：Archives of Oral Biology, 2014, 59(12): 1334-1341.

DOI：10.1016/j.archoralbio.2014.08.008

• Capsaicin
• Behaviour
• c-Fos
• Medullary dorsal horn
• Immunohistochemistry
• Nerve injury

Objective: To develop an objective method for assessing nociceptive behaviour in an animal model of capsaicin-induced intraoral pain. Changes in nociceptive responses were also examined after injury to the inferior alveolar nerve (IAN).
Design: Nociceptive responses evoked by the intraoral application of various doses of capsaicin were analyzed in lightly anaesthetized rats. The number of c-Fos protein-like immunoreactive (Fos-LI) neurons in the medullary dorsal horn (MDH) induced by the intraoral application of capsaicin was measured. Behavioural and c-Fos responses were also examined 14 days after injury to the IAN.
Results: Larger doses of intraoral capsaicin (1, 10 and 100 mu g) induced vigorous licking behaviour and c-Fos response in the MDH in a reproducible manner. The magnitudes of both behavioural activity and the c-Fos response from the 10 and 100 mu g doses of capsaicin were significantly greater than that by the 1 mu g dose. Injury to the IAN exaggerated the behavioural and c-Fos responses evoked by intraoral capsaicin.
Conclusions: The intraoral application of capsaicin is a valid and reliable method for studying intraoral pain and hyperalgesia following nerve injury.

• 出版日期2014-12