Fig. 4

Involvement of eicosanoids and endogenous phospholipases A₂ on MT-II- induced articular hyperalgesia. MT-II (10 μg/joint) or PBS (vehicle) was injected in tibio-tarsal articulation (25 μL). Pain threshold was determined using a modified electronic pressure-meter test 8 h after MT-II injection, and represented as force (in g). a Indomethacin, a cyclooxygenase inhibitor (Indo, 4 mg/kg, 30 min before MT-II) or (b) celecoxib, a type-2 cyclooxygenase inhibitor (Cel, 10 mg/kg, 60 min before MT-II) or (c) arachidonyl trifluoromethil ketone, a selective inhibitor of cPLA₂ (AACO, 200 μg/joint, 30 min before MT-II) or (d) palmitoyl trifluoromethyl ketone, an inhibitor of iPLA₂ (PACO, 1 μg/joint, 30 min before MT-II) was injected prior to MT-II. Each point represents the mean ± SEM of six animals. ***p < 0.001 indicate statistically significant differences when compared with control group (vehicle + vehicle). ##p < 0.01 and ###p < 0.001 indicate statistically significant differences when compared with MT-II group (MT-II + vehicle)