Participation of the NO/cGMP/K+ATP pathway in the antinociception induced by Walker tumor bearing in rats.
Braz J Med Biol Res
; 45(6): 531-6, 2012 Jun.
Article
em En
| MEDLINE
| ID: mdl-22450376
ABSTRACT
Implantation of Walker 256 tumor decreases acute systemic inflammation in rats. Inflammatory hyperalgesia is one of the most important events of acute inflammation. The L-arginine/NO/cGMP/K(+)ATP pathway has been proposed as the mechanism of peripheral antinociception mediated by several drugs and physical exercise. The objective of this study was to investigate a possible involvement of the NO/cGMP/K(+)ATP pathway in antinociception induced in Walker 256 tumor-bearing male Wistar rats (180-220 g). The groups consisted of 5-6 animals. Mechanical inflammatory hypernociception was evaluated using an electronic version of the von Frey test. Walker tumor (4th and 7th day post-implantation) reduced prostaglandin E(2)- (PGE(2), 400 ng/paw; 50 µL; intraplantar injection) and carrageenan-induced hypernociception (500 µg/paw; 100 µL; intraplantar injection). Walker tumor-induced analgesia was reversed (99.3% for carrageenan and 77.2% for PGE(2)) by a selective inhibitor of nitric oxide synthase (L-NAME; 90 mg/kg, ip) and L-arginine (200 mg/kg, ip), which prevented (80% for carrageenan and 65% for PGE(2)) the effect of L-NAME. Treatment with the soluble guanylyl cyclase inhibitor ODQ (100% for carrageenan and 95% for PGE(2); 8 µg/paw) and the ATP-sensitive K(+) channel (KATP) blocker glibenclamide (87.5% for carrageenan and 100% for PGE(2); 160 µg/paw) reversed the antinociceptive effect of tumor bearing in a statistically significant manner (P < 0.05). The present study confirmed an intrinsic peripheral antinociceptive effect of Walker tumor bearing in rats. This antinociceptive effect seemed to be mediated by activation of the NO/cGMP pathway followed by the opening of KATP channels.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Carcinoma 256 de Walker
/
Limiar da Dor
/
GMP Cíclico
/
Canais KATP
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Nociceptividade
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Analgésicos
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Óxido Nítrico
Tipo de estudo:
Etiology_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
2012
Tipo de documento:
Article