Articles: hyperalgesia.
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Lemnalol (8-isopropyl-5-methyl-4-methylene-decahydro-1,5-cyclo-naphthalen-3-ol) is a natural compound isolated from the marine soft coral Lemnalia cervicorni. In the present study, the anti-inflammatory and anti-nociceptive properties of lemnalol were investigated in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells and carrageenan-injected rats, respectively. Our results demonstrate that lemnalol significantly inhibited the expression of the pro-inflammatory proteins, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), in LPS-stimulated RAW 264.7 cells. ⋯ Moreover, post-intrathecal injection of lemnalol produced a dose-dependent anti-nociceptive effect in carrageenan-injected rats (1 and 5 microg). The present results indicate that the marine-derived compound lemnalol had anti-inflammatory and analgesic effects in LPS-stimulated RAW 264.7 cells and carrageenan-injected rats, respectively. In addition, inhibition of elevated iNOS and COX-2 protein expression as well as neurophil infiltration of carrageenan-injected paws may be involved in the beneficial effects of lemnalol.
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Using nociceptin-receptor-deficient mice, we studied the participation of nociceptin in herpetic and postherpetic allodynia in mice. Although nociceptin-receptor deficiency did not affect the development of skin lesions and herpetic allodynia, it prevented postherpetic allodynia. ⋯ Inhibition of herpetic allodynia by repeated oral administration of gabapentin (100 mg/kg) alleviated the overexpression of mRNA of pronociceptin, as well as the severity of postherpetic allodynia. These results suggest that the spinal nociceptin system is involved in the transitional process from herpetic allodynia to postherpetic allodynia.
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Honeybee's sting on human skin can induce ongoing pain, hyperalgesia and inflammation. Injection of bee venom (BV) into the intraplantar surface of the rat hindpaw induces an early onset of spontaneous pain followed by a lasting thermal and mechanical hypersensitivity in the affected paw. The underlying mechanisms of BV-induced thermal and mechanical hypersensitivity are, however, poorly understood. In the present study, we investigated the role of mitogen-activated protein kinase (MAPK) in the generation of BV-induced pain hypersensitivity. ⋯ The results indicate that differential activation of p38 and ERK1/2 in the dorsal horn may contribute to the generation and development of BV-induced pain hypersensitivity by different mechanisms.
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There is considerable research evidence supporting a palliative role for gamma-aminobutyric acid (GABA)-ergic neurotransmission and voltage-gated sodium channel blockade in neuropathic pain conditions. Hence, the present study was undertaken to assess the peripheral analgesic, antiallodynic and antihyperalgesic activities of the synthesized structural analogues of GABA. ⋯ In this study, we have demonstrated that combining phthalimide pharmacophore with GABA has evolved compounds effective for the treatment of neuropathic pain.
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Surgical removal of third molars may carry a risk of developing persistent orofacial pain, and central sensitization appears to play an important role in the transition from acute to chronic pain. ⋯ We found clear signs of sensitization of the trigeminal nociceptive system for at least one week after the surgery. Our results indicate that even a minor orofacial surgical procedure may be sufficient to evoke signs of both central and peripheral sensitization, which may play a role in the transition from acute to chronic pain in susceptible individuals.