LPS-induced mechanical inflammatory hyperalgesia depends on cytokines, prostaglandins and sympathomimetic amines.

<p>(<b>A</b>) LPS (100 ng/paw) was injected in TNFR1^+/+ (C57BL/6 background) or TNFR1^-/- (C57BL/6 background) mice. (<b>B</b>) C57BL/6 wild type mice were treated with anti-CXCL1 antibody (500 ng/paw, 5 min before LPS injection), or (<b>C</b>) IL-1ra (500 ng/paw, 5 min before LPS injection), or (<b>D</b>) indomethacin, (5 mg/kg, i.p. 30 min before LPS injection), guanethidine (30 mg/kg, s.c. 60 min before LPS injection) or indomethacin plus guanethidine (same doses). Mechanical hyperalgesia was evaluated 3 h after LPS injection. *<i>P</i><0.05 compared with saline control, #<i>P</i><0.05 compared with LPS control group; **<i>P</i><0.05 compared with indomethacin or guanethidine treated group. One-way ANOVA followed by Tukey's t test.