Effect of local anaesthesia on capsaicin-induced neurogenic inflammation.

摘要

Neurogenic inflammation has been associated with the development of temporomandibular disorders and noxious stimulation of the temporomandibular joint (TMJ) region has led to reflex excitation of masticatory muscles. The aim of this study was to evaluate the neurogenic component in acute TMJ inflammation by investigating the effect of local anesthetic blockade of afferent innervation on the development of capsaicin-induced edema in the rat TMJ region and on reflex jaw muscle activity. The application of capsaicin into the saline pre-treated TMJ region led to edema development and reflex jaw muscle activity. However, pre-treatment with bupivacaine failed to inhibit capsaicin-induced edema; whereas, reflex jaw muscle activity was abolished. Therefore, edema of the rat TMJ region developed independent of axonal conduction, suggesting inflammatory mediators such as neuropeptides may be directly released from primary afferent nerve terminals regardless of functional nerve conduction. Moreover, capsaicin-induced reflex jaw muscle activity appears to be centrally mediated.