Neuropeptides in temporomandibular joints with rheumatoid arthritis: a clinical study.

There is evidence that neuropeptides play a role in the development of arthritis. Synovial fluid from arthritic temporomandibular joints in patients with rheumatoid arthritis was therefore investigated for presence of the neuropeptides calcitonin gene-related peptide, substance P, neurokinin A and neuropeptide Y. All four peptides were found in the synovial fluid above plasma level, but calcitonin gene-related peptide showed the highest concentration and substance P the lowest.