Involvement of adenosine A1 and A2A receptors in (−)-linalool-induced antinociception

Activation of A1 or A2A receptors has been shown to induce antinociceptive effects, and the possible involvement of adenosine in (−)-linalool antinociceptive effect, has not been elucidated yet. Therefore, in the present study, we have investigated the effects of 1,3-dipropyl-8-cyclopentylxanthine (DPCPX), a selective adenosine A1 receptor antagonist and the effects of 3,7-dimethyl-1-propargilxanthine (DMPX), a selective adenosine A2A receptor antagonist on the antinociception of (−)-linalool in mice, measured in the hot-plate test. Both DPCPX (0.1 mg/kg; i.p.) and DMPX (0.1 mg/kg; i.p.) pre-treatment significantly depressed the antinociceptive effect of (−)-linalool at the highest doses tested. These findings demonstrated that the effect of (−)-linalool on pain responses is, at least partially, mediated by the activity of adenosine A1 and A2A receptors.