Fig. 5.

The anti-nociceptive effect of inosine in a glutamate-induced nociception model is mediated by adenosine A1 receptors. (a) Inosine dose-response curve. (b) DPCPX—an adenosine A1 antagonist—inhibited the anti-nociceptive effect of inosine. (c) ZM241385—an adenosine A2a antagonist—did not affect the anti-nociceptive effect of inosine. Inosine was administered by the intraplantar route 5 minutes before glutamate injection. DPCPX or ZM241385 was administered by the intraplantar route 5 minutes before inosine. Data are presented as mean±S.E.M. Statistical analysis was performed using one-way ANOVA followed by Student-Newman-Keuls post hoc test. s, seconds. *p<0.05, **p<0.01, and ***p<0.001 for comparisons of the effects of agonists and antagonists with those of vehicle. ^# denotes significant statistical difference compared with inosine (10 μg/paw) group in absence of DPCPX. n = 3−5 total male and female mice