title: Caffeine reverses antinociception by oxcarbazepine by inhibition of adenosine A1 receptors: insights using knockout mice.
abstract: Oxcarbazepine is an anticonvulsant drug that has been explored as a novel therapeutic agent to treat neuropathic pain in humans. It produces antinociception in several preclinical models of pain, and these actions are blocked by methylxanthine adenosine receptor antagonists which implicates adenosine it its actions. In this study, the antinociceptive effect of oxcarbazepine, and the ability of caffeine to reverse its actions, were examined using the formalin test (2%) in wild-type mice and in mice lacking adenosine A(1) receptors by way of further exploring the involvement of adenosine in its actions. Oxcarbazepine produced dose-related suppression of formalin-evoked flinching responses in wild-type mice following both systemic and intraplantar administration, and this action was reversed by systemic and intraplantar administration of caffeine, respectively. The ability of oxcarbazepine to inhibit flinching after systemic and intraplantar administration was unaltered in homozygous (-/-) and heterozygous (+/-) adenosine A(1) receptor knockout mice. However, caffeine no longer reversed this antinociception. Our results indicate that, while adenosine A(1) receptors are not required for oxcarbazepine to produce antinociception in knockout mice, such receptors are essential in order to see caffeine reversal of this antinociceptive effect.
authors.affiliation: Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4H7. jana.sawynok@dal.ca
authors.forename: Jana
authors.initials: J
authors.lastname: Sawynok
authors.forename: Allison R
authors.initials: AR
authors.lastname: Reid
authors.forename: Bertil B
authors.initials: BB
authors.lastname: Fredholm
mesh_terms: D058916:Adenosine A1 Receptor Antagonists; D000700:Analgesics / Q000494:pharmacology* / Q000627:therapeutic use; D000818:Animals; D002110:Caffeine / Q000494:pharmacology*; D002220:Carbamazepine / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D004336:Drug Antagonism; D005260:Female; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D000078330:Oxcarbazepine; D010146:Pain / Q000188:drug therapy / Q000503:physiopathology*; D010147:Pain Measurement; D043682:Receptor, Adenosine A1 / Q000235:genetics
chemical_list: D058916:Adenosine A1 Receptor Antagonists; D000700:Analgesics; D043682:Receptor, Adenosine A1; D002220:Carbamazepine; D002110:Caffeine; D000078330:Oxcarbazepine