EFFECT OF ADENOSINE RECEPTOR AGONIST AND ANTAGONIST ON NICOTINE INDUCED ANTINOCICEPTION IN MICE

In this study analgesia induced by different dosages of nicotine was examined on mice. Nicotine with different dosages (0.1, 0.01, 0.001 mg/kg) was injected by intraperitoneal manner. Formalin test was then performed after ten minutes. Nicotine caused both acute and chronic phase analgesia with all dosages. We used, but the most analgesic dose was 0.1 mg/kg. Theophyline is an adenosin receptor antagonist, wich induces analgesia with low dasages (5, 10, 20 mg/kg) but not at higher dasages (40, 50 mg/kg). On the other hand, theophyline reduces the level of analgesia induced by nicotine. Furthermore NECA, an adenosine receptor agonist, causes not only analgesia, but also augments the analgesic effect of nicotine. Thus, we concluded that adenosine has some roles on analgesic effects of nicotine.