까le orofacial pain is one of the most common types of acute or chronic pain, and many forms of orofacial pain have an inflammatory component. The aim of this study was to develop a behavioral model of orofacial pain associated with chronic int1ammation in rats. 까le int1ammatory agent, CFA suspended in an oil/saline (1 :1) emulsion (50 씨) was injected into the vibrissal pad of adult male rats. A s따피ar application of saline was served as control. Spontaneous and mechanically evoked behaviours were monitored daily in awake rats before and up to 6 weeks after injection. As for the spontaneous behaviour, total time rat spent in face gr∞ming was counted. For the measurement of mechanically evoked behaviour, the threshold and frequency of head withdrawal response (HWR) were determined at the vibrissal pad with the use of von Frey nylon monofilaments. CFA injection did not produce any significant changes in face gr∞ming， but produced a s핑nificant reduction in HWR threshold and a s핑nificant increase in HWR frequency to mechanical stimulation of the vibrissal pad on the ipsilateral side for approximately 4-6 weeks. Saline injection into the vibrissal pad did not produce any significant changes in spontaneous and mechanically evoked behaviours. These results indicate that the injection of CFA into orofacial cutaneous tissues can induce persistent behavioral allodynia and hyperalgesia, and easily quantified behavioral model will provide a better understanding of mechanisms and control of orofacial chronic pain conditions associated with int1ammation.

• 박수정(전북대학교 치과대학 구강생리학교실 및 구강생체과학연구소) | Soo Joung Park