Resumen de Substance P-Associated Increase of Intra-articular Temperature and Pain Threshold in the Arthritic TMJ

Elvar Theodorsson, Thomas Lundeberg, Anna Appelgren, Sigvard Kopp, Björn Appelgren

• Neuropeptides are considered mediators and modulators of inflammatory joint disease. Substance P (SP) has been proposed as a mediator of pain, and its vasoactive properties are well documented. In this study, the presence of SP-like immunoreactivity in the synovial fluid was correlated to intra-articular temperature (IAT) and pain from the arthritic temporomandibular joint (TMJ) 3 to 5 weeks after one intra-articular injection of glucocorticosteroids. Eighteen TMJs were investigated for IAT and the presence of SP-like immunoreactivity in the synovial fluid in 12 patients with systemic inflammatory joint disease. After arthrocentesis, the aspirates were analyzed for SP-like immunoreactivity by means of competitive radio immunoassay. A visual analogue scale and an algometer determining the rpessure pain threshold and tolerance level assessed arthritic pain and hyperalgesia in the TMJ. Our results indicate that SP-like immunoreactivity is associated with IAT and that increased concentrations of joint fluid SP-like immunoreactivity correspond to increased pain threshold and tolerance and a concomitantly decreased visual analogue scale.