Fig. 2. Effect of acute and chronic immobilization stress on pain regulation in tail-flick, writhing, and formalin pain models. (A) Tail-flick test; (B) Writhing test; (C) Formalin-induced pain model-1st phase; (D) Formalin-induced pain model-2nd phase. The response time of tail-flick to radiant heat was measured. The number of writhing responses was counted for 30 min after acetic acid injection. In the formalin pain test, the pain behaviors such as vigorous licking and shaking paws were counted during the first (0~5 min) and the second (20~40 min) phases using a stopwatch. The vertical bars indicate the standard error of mean (*p<0.05, **p<0.01, ***p<0.001 compared to Control group). The mice number of animals used in each group was 10.
© Exp Neurobiol
