Fig. 9
The influence of AM 251 and ZD 7288 on hyperalgesia in CM rats. A The mechanical pain thresholds of the periorbital region in the CM group were materially lower than in the Sham group, and there was no obvious difference between the CM and CM + Vehicle groups. Compared to the CM + Vehicle group, the mechanical pain thresholds of the periorbital region in the CM + AM 251 (40 μg) group were visibly decreased. The mechanical pain thresholds of the periorbital region in the CM + Vehicle group were indistinguishable from the CM + AM 251 (4 μg) group. (n = 6/group, *p < 0.05, **p < 0.01, N, S, not significant). B No substantial difference was observed in the mechanical pain thresholds of the periorbital region among the Sham, Sham + Vehicle, and Sham + AM 251 (40 μg) groups. (n = 6/group, N, S, not significant). C The mechanical pain thresholds of the periorbital region were robustly decreased in the CM group compared with those in the Sham group, and the mechanical pain thresholds of the periorbital region in the CM + AM 251 group were further drastically reduced compared to those the CM group. However, The mechanical pain thresholds of the periorbital region were significantly increased in the CM + AM 251 + ZD 7288 group compared to those in the CM + AM 251 group. (n = 6/group, *p < 0.05, **p < 0.01, N, S, not significant)