Caffeine and a selective adenosine A2B receptor antagonist but not imidazoline receptor antagonists modulate antinociception induced by diphenyl diselenide in mice

The present study examined the antinociceptive effect of diphenyl diselenide (PhSe)2, given orally (p.o.), in the hot-plate test in mice. The administration of diphenyl diselenide (10–100 mg/kg, p.o.) caused a significant inhibition of thermal nociception induced by hot-plate test in mice. Pretreatment of animals by intraperitoneal route (i.p.) with caffeine (10 mg/kg; a non-specific adenosine receptor antagonist) and PSB1115 (1 mg/kg; an adenosine A2B receptor antagonist), but not DPCPX (2 mg/kg; an adenosine A1 receptor antagonist) and SCH5826 (3 mg/kg; an adenosine A2A receptor antagonist) significantly blockaded the antinociceptive effect caused by diphenyl diselenide (10 mg/kg, p.o.) in the hot-plate test. Moreover, the pretreatment of animals with efaroxan (1 mg/kg, i.p.; a mixed I1 imidazoline/α2-adrenoceptor antagonist) and idazoxan (3 mg/kg, i.p.; a mixed I2 imidazoline/α2-adrenoceptor antagonist) did not significantly reverse the antinociception caused by oral administration of diphenyl diselenide (10 mg/kg, p.o.) in the hot-plate test. These results indicate that diphenyl diselenide produced antinociception in a thermal model of pain in mice and its effect was prevented by caffeine and by a selective adenosine A2B receptor, but not by imidazoline receptor antagonists in mice.