Figure 1

Injection of CFA into the TMJ produces plasma extravasation and mechanical allodynia. (A) The development of inflammation was analyzed by injecting the Evans' blue dye through the tail vein. A significantly higher amount of dye was extracted from the ipsilateral TMJs of CFA-injected rats compared to the contralateral side at both 24 h and 72 h p.i. Since no significant differences between saline-injected rats at 24 h and 72 h have been observed, data have been pooled together, and shown here as "saline". (B) Rats were tested for the development of mechanical allodynia by probing the contralateral (contra) and ipsilateral (ipsi) orofacial regions with von Frey filaments before (pre) and post injection of saline or CFA into the TMJ. The head withdrawal threshold force, in grams (g), was measured. Y-axis = log₁₀ scale. ** p < 0.01, and * p < 0.05 compared to the contralateral side of CFA-injected rats, # p < 0.01 compared to the contralateral tissue; one-way ANOVA.