Figure 2.

Development of mechanical allodynia in TMJ induced by CFA in rats. Head withdrawal threshold was measured using an electric von Frey anesthesiometer over a 96-hour period for the saline control group (open squares) and the CFA group (filled triangles). CFA was injected at time 0 and the withdrawal threshold was measured at time points 6 h, 12 h, 24 h, 48 h, and 96 h. The lowest head withdrawal threshold occurred 12 h after CFA injection and was maintained for about 36 h (P < 0.001 for time period of 12 to 96 hours, compared with the saline group, two-way ANOVA).