Involvement of alpha2-adrenergic mechanisms in experimental analgesic and anti-inflammatory activities of a benzamide derivative.

Several non-steroidal anti-inflammatory drugs of the N-pyridinyl-benzamide series that produce experimental peripheral and central anti-inflammatory effects possess a dopaminomimetic component and inhibit eicosanoid synthesis without acting directly on the enzymes classically involved in this process. We compared the anti-inflammatory and analgesic activities of one of the most active benzamide derivatives with those of clonidine. Rat paw and brain edemas were inhibited by these two agents, whereas different methods showed that yohimbine counteracted this effect and the analgesia it induced. The involvement of an alpha2-adrenergic and/or serotoninergic components in these activities is considered, without excluding the possibility that the mechanism of action is in part due to inhibition of prostaglandin synthesis.