Simultaneous Inhibition of PGE₂ and PGI₂ Signals Is Necessary to Suppress Hyperalgesia in Rat Inflammatory Pain Models

Figure 4

Analgesic effect of compound I and celecoxib in yeast-induced acute inflammatory pain in rats. (a) Effect of compound I and celecoxib on inflamed paw prostanoids’ production in yeast-induced acute inflammatory pain model. Inflamed paw was obtained after the last measurement of pain threshold. (b) Effect of compound I and celecoxib on lumbar area of spinal cord prostanoid production in yeast-induced acute inflammatory pain model. Spinal cord was obtained after the last measurement of pain threshold. (c) Time course of pain threshold. Male Wistar-Imamichi rats received a single, right hind-paw intradermal injection of dead Brewer’s yeast (20%/0.1 mL/paw). After 18.5 h, compounds or 0.5% MC were administered orally to animals with established hyperalgesia (pain threshold: 60~120 g). Pain response was examined 1, 2, 3, and 4 h after administration. Results are shown as the mean ± SEM ( = 6/group). The statistical analysis was performed by Dunnett’s test and Steel’s test for prostanoids’ content ((a) and (b)) and pain threshold (c), respectively. ; for compound treated versus 0.5% MC (0 mg/kg) treated animals.

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