Role of the kappa-opioid system in the attenuation of the morphine-induced place preference under chronic pain.
Life Sci
; 64(1): PL1-7, 1999.
Article
em En
| MEDLINE
| ID: mdl-10027746
ABSTRACT
We previously reported that the morphine-induced place preference was attenuated under inflammation produced by the unilateral injection of 2.5 % formalin (50 microl) into the hind paw of rats. In the present study, to elucidate the mechanism of this attenuation, the effects of pretreatment with delta- and kappa-opioid receptor antagonists, naltrindole (NTI) and nor-binaltorphimine (nor-BNI), on the development of the morphine-induced place preference under inflammation were examined in rats. Nor-BNI, but not NTI, eliminated the suppression of the morphine-induced place preference in inflamed groups. These results suggest that endogenous kappa-opioid systems may be activated in the presence of chronic inflammatory nociception; as a result, the development of morphine's rewarding effect may be suppressed under inflammation.
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Base de dados:
MEDLINE
Assunto principal:
Dor
/
Recompensa
/
Receptores Opioides kappa
/
Morfina
Idioma:
En
Ano de publicação:
1999
Tipo de documento:
Article