Figure 2
Mechanical hyperalgesia/allodynia following ligation of the masseter tendon. The orofacial skin site above the TASM was probed with a series of von Frey microfilaments. The EF50s were derived from the respective stimulus-response frequency function curves and are plotted against time after surgery. A significant reduction of EF50 indicates increased mechanical sensitivity, or mechanical hyperalgesia and allodynia. Note log scales for the ordinate. Filled circles show group means and open circles indicate individual EF50 of the side ipsilateral to injury. Error bars are 95% confidence intervals of EF50s. a. Rats receiving ligation of the TASM (n = 14). A significant reduction of EF50 indicating significant mechanical allodynia occurred ipsilateral to injury at 3 d and was maintained through the 8-week period. There was no change in EF50 on the equivalent contralateral site. b. Sham-operated rats showed a temporary reduction of EF50 at 3 d ipsilateral to intraoral procedure (n = 14). *, p < 0.01 vs. contralateral site.