The involvement of peripheral alpha 2-adrenoceptors in the antihyperalgesic effect of oxcarbazepine in a rat model of inflammatory pain.
Anesth Analg
; 105(5): 1474-81, table of contents, 2007 Nov.
Article
en En
| MEDLINE
| ID: mdl-17959985
ABSTRACT
BACKGROUND:
We studied whether peripheral alpha2-adrenergic receptors are involved in the antihyperalgesic effects of oxcarbazepine by examining the effects of yohimbine (selective alpha2-adrenoceptor antagonist), BRL 44408 (selective alpha(2A)-adrenoceptor antagonist), MK-912 (selective alpha2C-adrenoceptor antagonist), and clonidine (alpha2-adrenoceptor agonist) on the antihyperalgesic effect of oxcarbazepine in the rat model of inflammatory pain.METHODS:
Rats were intraplantarly (i.pl.) injected with the proinflammatory compound concanavalin A (Con A). A paw-pressure test was used to determine 1) the development of hyperalgesia induced by Con A; 2) the effects of oxcarbazepine (i.pl.) on Con A-induced hyperalgesia; and 3) the effects of i.pl. yohimbine, BRL 44408, MK-912 and clonidine on the oxcarbazepine antihyperalgesia.RESULTS:
Both oxcarbazepine (1000-3000 nmol/paw; i.pl.) and clonidine (1.9-7.5 nmol/paw; i.pl.) produced a significant dose-dependent reduction of the paw inflammatory hyperalgesia induced by Con A. Yohimbine (260 and 520 nmol/paw; i.pl.), BRL 44408 (100 and 200 nmol/paw; i.pl.) and MK-912 (10 and 20 nmol/paw; i.pl.) significantly depressed the antihyperalgesic effects of oxcarbazepine (2000 nmol/paw; i.pl.) in a dose-dependent manner. The effects of antagonists were due to local effects since they were not observed after administration into the contralateral hindpaw. Oxcarbazepine and clonidine administered jointly in fixed-dose fractions of the ED(50) (1/4, 1/2, and 3/4) caused significant and dose-dependent reduction of hyperalgesia induced by Con A. Isobolographic analysis revealed an additive antihyperalgesic effect.CONCLUSIONS:
Our results indicate that the peripheral alpha2A and alpha2C adrenoceptors could be involved in the antihyperalgesic effects of oxcarbazepine in a rat model of inflammatory hyperalgesia.
Buscar en Google
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Dolor
/
Carbamazepina
/
Receptores Adrenérgicos alfa 2
/
Modelos Animales de Enfermedad
/
Hiperalgesia
Límite:
Animals
Idioma:
En
Revista:
Anesth Analg
Año:
2007
Tipo del documento:
Article