Selective for COX-2 over COX-1, compound 10 exhibited IC<sub>50</sub> 0.02 µM for COX-2 and reversed acetic acid induced inflammation in rats by 73% when used at 10 mg kg<sup>-1</sup> dose and the same dose of the compound also rescued the animals from inflammatory phase of formalin induced hyperalgesia.
Multiple pro-inflammatory cytokines and mediators are produced during neurogenic inflammation and aberrant control of COX-2 mRNA turnover may be implicated in diseases including chronic inflammation, which results in inflammation-derived hyperalgesia around primary sensory neurons.
In addition to arachidonic acid, COX-2 oxidizes the endocannabinoid 2-arachidonoylglycerol (2-AG) to produce prostaglandin E<sub>2</sub> (PGE<sub>2</sub>)-glycerol (PGE<sub>2</sub>-G); PGE<sub>2</sub>-G is known to produce hyperalgesia.
These results suggest that minocycline provides protection against neonatal systemic LPS exposure-induced enhanced pain sensitivity (allodynia and hyperalgesia), and that the protective effects may be associated with its ability to attenuate LPS-induced microglia activation, and the levels of IL-1β, COX-2, and PGE2 in the spinal cord of neonatal rats.
The effects of the COX-2 inhibitor, parecoxib (intraperitoneal 10 mg kg<sup>-1</sup>), or the EP-1R antagonist, SC51089 (intraperitoneal 100 μg kg<sup>-1</sup>), on hyperalgesia and spinal PGE2 were examined.
Suppression of hyperexcitability of trigeminal nociceptive neurons associated with inflammatory hyperalgesia following systemic administration of lutein via inhibition of cyclooxygenase-2 cascade signaling.
This study investigated whether 14 days of the selective Cox-2 inhibitor etoricoxib (60 mg/day) would modify self-report of pain intensity and quality, and physical measures of hyperalgesia and function in individuals with knee OA.
The prevention of this hyperalgesia by diclofenac (1-10μg), the inhibitors of COX-1 SC-560 (0.1-1μg) or COX-2 celecoxib (1-5μg), the TRPV1 antagonist capsazepine (0.03-0.3μg) or the TRPA1 antagonist HC030031 (10-50μg) demonstrates the involvement of prostaglandin synthesis and TRP sensitization in CCL5-evoked hyperalgesia.
Moreover, TMJ inflammation-induced upregulation of Na<sub>v</sub>1.7 expression and PGE<sub>2</sub> levels in the TG could be reversed by COX-2-selective inhibitor meloxicam given by oral gavage, and meanwhile, the hyperalgesia of inflamed TMJ was also mitigated.
These results indicate that intrathecal administration of COX-2 inhibitors has an anti-hyperalgesic effect on streptozotocin-induced mechanical hyperalgesia and we concluded that spinal COX-2 is pivotal in streptozotocin-induced hyperalgesia.