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Participation of cannabinoid receptors in peripheral nociception induced by some NSAIDs.
Silva, L C R; Romero, T R L; Guzzo, L S; Duarte, I D G.
Afiliação
  • Silva LC; Departamento de Farmacologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil.
Braz J Med Biol Res ; 45(12): 1240-3, 2012 Dec.
Article em En | MEDLINE | ID: mdl-22983178
Nonsteroidal anti-inflammatory drugs (NSAIDs) have been used extensively to control inflammatory pain. Several peripheral antinociceptive mechanisms have been described, such as opioid system and NO/cGMP/KATP pathway activation. There is evidence that the cannabinoid system can also contribute to the in vivo pharmacological effects of ibuprofen and indomethacin. However, there is no evidence of the involvement of the endocannabinoid system in the peripheral antinociception induced by NSAIDs. Thus, the aim of this study was to investigate the participation of the endocannabinoid system in the peripheral antinociceptive effect of NSAIDs. All experiments were performed on male Wistar rats (160-200 g; N = 4 per group). Hyperalgesia was induced by a subcutaneous intraplantar (ipl) injection of prostaglandin E2 (PGE2, 2 µg/paw) in the rat's hindpaw and measured by the paw pressure test 3 h after injection. The weight in grams required to elicit a nociceptive response, paw flexion, was determined as the nociceptive threshold. The hyperalgesia was calculated as the difference between the measurements made before and after PGE2, which induced hyperalgesia (mean = 83.3 ± 4.505 g). AM-251 (80 µg/paw) and AM-630 (100 µg/paw) were used as CB1 and CB2 cannabinoid receptor antagonists, respectively. Ipl injection of 40 µg dipyrone (mean = 5.825 ± 2.842 g), 20 µg diclofenac (mean = 4.825 ± 3.850 g) and 40 µg indomethacin (mean = 6.650 ± 3.611 g) elicited a local peripheral antinociceptive effect. This effect was not antagonized by ipl CB1 cannabinoid antagonist to dipyrone (mean = 5.00 ± 0.9815 g), diclofenac (mean = 2.50 ± 0.8337 g) and indomethacin (mean = 6.650 ± 4.069 g) or CB2 cannabinoid antagonist to dipyrone (mean = 1.050 ± 6.436 g), diclofenac (mean = 6.675 ± 1.368 g) and indomethacin (mean = 2.85 ± 5.01 g). Thus, cannabinoid receptors do not seem to be involved in the peripheral antinociceptive mechanism of the NSAIDs dipyrone, diclofenac and indomethacin.
Assuntos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Anti-Inflamatórios não Esteroides / Receptor CB1 de Canabinoide / Receptor CB2 de Canabinoide / Nociceptividade / Agonistas de Receptores de Canabinoides Limite: Animals Idioma: En Revista: Braz J Med Biol Res Ano de publicação: 2012 Tipo de documento: Article País de afiliação: Brasil País de publicação: Brasil

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Anti-Inflamatórios não Esteroides / Receptor CB1 de Canabinoide / Receptor CB2 de Canabinoide / Nociceptividade / Agonistas de Receptores de Canabinoides Limite: Animals Idioma: En Revista: Braz J Med Biol Res Ano de publicação: 2012 Tipo de documento: Article País de afiliação: Brasil País de publicação: Brasil