Adenosine receptor ligands and dizocilpine-induced antinociception in mice.

Interactions between adenosine receptor ligands and dizocilpine (uncompetitive NMDA receptor antagonist) was studied in antinociceptive, writhing test in mice. Minimal effective, antinociceptive doses of adenosine receptor agonists were: 0.1 mg/kg (NECA--A1/A2 agonist). Generally, these agonists did not potentiate the subthreshold dose of dizocilpine (0.05 mg/kg). Of all adenosine receptor antagonists used, only caffeine (A2 and A2 antagonists) reversed dizocilpine-induced (0.1 mg/kg) antinociception dose-dependently. These findings indicate that dizocilpin-induced antinociception in the writhing test is only partly influenced by adenosine receptor ligands.