Antinociceptive effects of H3 (R-methylhistamine) and GABA(B) (baclofen)-receptor ligands in an orofacial model of pain in rats.
Neurotox Res
; 24(2): 258-64, 2013 Aug.
Article
de En
| MEDLINE
| ID: mdl-23463522
ABSTRACT
The present study explored the antinociceptive effects of H3 (R-methylhistamine) and GABA(B) (baclofen) receptor ligands in an orofacial model of pain in rats. Orofacial pain was induced by subcutaneous injection of formalin (50 µl, 5 %) in the upper lip region, and the number of jumps and time spent face rubbing was recorded for 40 min. Formalin produced a marked biphasic pain response; first phase, 0-10 min (jumps), and second phase, 15-40 min, (rubbing). Baclofen (50 µg) injected into the rat wiskerpad 5 min before formalin administration suppressed both phases of pain whereas R-alpha-methylhistamine (12.5 µg) abolished the first phase only. Brains were taken immediately after behavioral testing was completed. HPLC/ED analysis showed that 5-hydroxytryptamine (5-HT) turnover was increased in hippocampus, thalamus, and brain stem of all formalin groups, excepting the baclofen group in which the balance of 5-HT metabolism was restored to control values. These findings demonstrate that GABA(B) receptors represent peripheral targets for analgesia. Consequently, locally administered baclofen may be a useful approach in treating inflammatory trigeminal pain.
Texte intégral:
1
Collection:
01-internacional
Base de données:
MEDLINE
Sujet principal:
Baclofène
/
Algie faciale
/
Méthylhistamines
/
Agonistes histaminergiques
/
Modèles animaux de maladie humaine
/
Agonistes du recepteur GABA-B
Type d'étude:
Prognostic_studies
Limites:
Animals
Langue:
En
Journal:
Neurotox Res
Sujet du journal:
NEUROLOGIA
Année:
2013
Type de document:
Article
Pays d'affiliation:
Pologne