title: Interactions between guanabenz and clonidine in their antinociceptive effects in the rat.
abstract: Based on the hot-plate algesiometric assay in conscious Sprague-Dawley rats, we observed that both guanabenz and clonidine, at a subcutaneous dose of 5 and 1 mg/kg, respectively, exhibited significant antinociceptive potencies. Paradoxical actions on the hot-plate responses, however, were exerted by guanabenz at lower doses, varying from hyperalgesia (1 mg/kg) to no effect (2 mg/kg). A pretreatment of clonidine (1 mg/kg) substantially potentiated the antinociceptive efficacy of the two latter doses, but failed to further augment the pain-suppressive action of guanabenz at 5 mg/kg. These interactive effects of the two alpha-adrenoceptor agonists suggest that they may share a common mechanism(s) in their analgesic actions.
mesh_terms: D000700:Analgesics; D000818:Animals; D003000:Clonidine / Q000494:pharmacology*; D004347:Drug Interactions; D006143:Guanabenz / Q000494:pharmacology*; D006146:Guanidines / Q000494:pharmacology*; D008297:Male; D010147:Pain Measurement; D051381:Rats; D011919:Rats, Inbred Strains; D011930:Reaction Time
chemical_list: D000700:Analgesics; D006146:Guanidines; D006143:Guanabenz; D003000:Clonidine