DefinePK

Abstract

Previous studies indicate that inflammatory processes of the temporomandibular joint (TMJ) may easily trigger pain. In this study, we tested the effects of two anti-inflammatory drugs on the response properties of C-polymodal nociceptors from the rat&#146;s TMJ, in vitro. Male Wistar rats weighing 250 to 350 g were used. C-polymodal units were identified based on conduction velocity (<2.0 m sec-1) and responsiveness to thermal stimuli. Nociceptive responses were induced by injection of bradykinin (BK) into the TMJ area, followed immediately by the topical application of either flurbiprofen, dexamethasone, or physiological saline (as a control) to the receptive field. Both flurbiprofen and dexamethasone significantly reduced the BK-induced firing rate of nociceptive units. In addition, both drugs significantly reduced the BK-induced mechanical sensitization. However, flurbiprofen and dexamethasone worked in different time windows through clearly different mechanisms, suggesting that the concomitant use of these drugs could be even more effective than either drug alone.