Mechanical allodynia in chronic inflammatory muscle pain. Intramuscular injections of carrageenan were given on day 1 and 5. The data is plotted as percentage of responses out of 10 mechanical stimuli over the dorsum of the foot at an interval of 5 min. Wild-type, n = 5 mice; AC1&8 DKO, n = 8 mice. A. The behavioral responses of animals to a non-noxious mechanical stimulus were recorded on the ipsilateral side. 5b denotes time point before second injection of carrageenan on day 5; 5a denotes time point after second injection of carrageenan on day 5. B. Mechanical allodynia on day 5 following the second intramuscular injection of carrageenan. There was no statistical difference between the wild-type and DKO mice on both ipsilateral and contralateral sides. C. Mechanical allodynia on day 9. Significant differences in mechanical allodynia were present between the wild-type and DKO mice on both ipsilateral and contralateral sides. p < 0.05. *Significant difference from wild-type mice.