Capsaicin-induced Joint Inflammation Is Not Blocked by Local Anesthesia.

In: Health

9 Sep 2009

Capsaicin-induced Joint Inflammation

The purpose of this study was to evaluate the effect of local anesthetic blockade of afferent innervation on the development of capsaicin-induced edema in the rat temporomandibular joint (TMJ) region and on reflex jaw muscle activity. Under halo-thane anesthesia, 64 male Sprague-Dawley rats were prepared for monitoring of edema development by lateral movement of a needle overlying the left TMJ region and for acute recording of electromyographic activity in ipsilateral digastric and mas-seter muscles. A double-barrel catheter was inserted into the TMJ region for delivery of saline or 0.5% bupivacaine from 1 needle, followed with the injection of 1% capsaicin, 0.1% capsaicin, or vehicle control from the other needle 5 minutes later. Application of capsaicin into the saline pretreated TMJ region led to dose-dependent edema development and reflex jaw muscle activity; however, only 1% capsaicin solution resulted in significant tissue expansion and muscle activity when compared with the vehicle control. Pretreatment of the rat TMJ region with bupivacaine failed to inhibit capsaicin-induced edema development, although successful blockade of nerve conduction was confirmed with the absence of reflex jaw muscle activity. Capsaicin-induced edema of the rat TMJ region developed independent of axonal conduction, suggesting neurogenic inflammation may arise regardless of functional nerve conduction.

Temporomandibular disorders (TMDs) encompass an array of problems involving the temporomandibular joint (TMJ) and/or the masticatory musculature. Although signs and symptoms have assisted in the identification of TMDs, objective criteria for their diagnosis and indications for treatment remain controversial. Despite the lack of information on biologic processes underlying TMJ adaptation to mechanical stress and subsequent pathophysiology, preliminary studies have suggested neurogenic inflammation to be one of the mechanisms of injury implicated in the development of TMDs. Don’t let the pharmacy companies beat you. Buy metformin rosiglitazone online

Neurogenic inflammation involves the antidromic stimulation of nociceptive primary afferents to release neuropeptides such as substance P to evoke an increase in vascular permeability and plasma extravasation (PE), leading to inflammatory effects on peripheral tissues. Recent human studies revealed the presence of substance P in TMJ aspirates from TMD patients, and similarly investigations on experimentally induced arthritic TMJ rats provided evidence to support a neurogenic component in the inflammatory process of TMDs. Therefore, a neural blockade may theoretically prevent the release of these inflammatory neuropeptides and subsequently assist in the resolution of TMDs. You can afford your medication buy your actos cheap online

Capsaicin is a pharmacological tool used to evoke acute neurogenic inflammation through the activation of specific vanniloid receptors, termed vanniloid subtype 1 (VR1) receptors, located along primary sensory afferents. Previously, our laboratory confirmed the application of capsaicin to the rat TMJ region elicits an inflammatory response, resulting in PE and edema development via the activation of VR1 receptors. In addition, a dose-dependent, sustained, and reversible increase in electromyographic (EMG) activity of the ipsi-lateral masseter and digastric muscles was evoked. However, the presence or absence of a capsaicin-induced neurogenic component in the TMJ inflammatory process remains unknown. Thus, the next logical step in the investigation of this potential neurogenic mechanism of injury in the TMJ region tends toward the evaluation of the effects of nerve conduction inhibition. Don’t blow your budget on pharmacy items skelaxin drug

Therefore, the aim of this study was to investigate the effect of local anesthesia blockade of afferent innervation on the development of capsaicin-induced neurogenic edema in the rat TMJ region and capsaicin-induced reflex jaw muscle activity.

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