PARTICIPATION OF CANNABINOID RECEPTORS IN ANTIPRURITIC ACTIVITY INDUCED BY SYSTEMIC DIPYRONE IN MICE

Aims: The cannabinoid system has been shown to contribute to the antinociceptive effects of nonsteroidal anti- inflammatory drugs. Considering the similar pathophysiological mechanisms underlying pain and itching, we aimed to observe whether dipyrone has an antipruritic effect and whether cannabinoid receptors are involved in this effect. Methods: In this project, we produced scratching behavior in BALB/c mice, intradermally administering the well- known pruritic agent compound 48/80. After observing the anti-scratching effect of dipyrone with increasing doses, we administered AM-251 (1 mg/kg, intraperitoneal) and AM-630 (3 mg/kg, intraperitoneal) to determine whether the endocannabinoid system was associated with this effect of dipyrone. Results: Dipyrone reduced scratching behavior at its highest dose used in this study (600 mg/kg); however, neither AM-251 nor AM-630 changed the antipruritic action of dipyrone. Conclusion: Our findings indicate that dipyrone, at higher doses, attenuates compound 48/80-induced scratching behavior in mice. Cannabinoid receptors have been found not to be involved in the antipruritic effect of dipyrone. Further experiments are required to delineate the mechanisms underlying this high-dose dipyrone effect. Keywords: AM-251, AM-630, dipyrone, pruritus