Peripheral antinociception by carbamazepine in an inflammatory mechanical hyperalgesia model in the rat: a new target for carbamazepine?

This study investigated whether carbamazepine could produce local peripheral antinociception in a rat model of inflammatory mechanical hyperalgesia, and whether adenosine receptors are involved. Carbamazepine (100-1000 nmol/paw) co-administrated with a pro-inflammatory compound, concanavalin A, into the hind paw caused a significant dose- and time-dependent anti-hyperalgesia. Coadministration of caffeine (250-1000 nmol/paw), a nonselective adenosine-receptor antagonist, as well as DPCPX (10-30 nmol/paw), a selective adenosine A(1)-receptor antagonist, with carbamazepine, significantly depressed its anti-hyperalgesic effect. Drugs injected into the contralateral hind paw did not produce significant effects. These results suggest that carbamazepine produces local peripheral anti-hyperalgesia via peripheral adenosine A(1) receptors.