5-HT induces temporomandibular joint nociception in rats through the local release of inflammatory mediators and activation of local β adrenoceptors.
The 5-hydroxytryptamine (serotonin, 5-HT) is an important inflammatory mediator found in high levels in the synovial fluid of the temporomandibular joint (TMJ) of patients with inflammatory pain. In this study, we used the nociceptive behavior responses, measured as flinching the head and rubbing the orofacial region, as a nociceptive assay. We demonstrated that the local blockade of the 5-HT₃ receptor and β₁ or β₂-adrenoceptors, the depletion of norepinephrine in the sympathetic terminals and the local inhibition of cyclooxygenase significantly reduced 5-HT-induced TMJ nociception. These results demonstrated that 5-HT induces nociception in the TMJ region by the activation of β₁ and β₂ adrenoceptors located in the TMJ region and local release of sympathetic amines and prostaglandins. Therefore, the high levels of 5-HT in the synovial fluid of patients with TMJ inflammatory pain may contribute to TMJ pain by similar mechanisms.
Department of Structural and Functional Biology, Institute of Biology, State University of Campinas-UNICAMP, Monteiro Lobato 255, 13083-862 Campinas, SP, Brazil.
Maria Cláudia G
MC
Oliveira-Fusaro
Juliana Trindade
JT
Clemente-Napimoga
Juliana Maia
JM
Teixeira
Karla Elena
KE
Torres-Chávez
Carlos Amílcar
CA
Parada
Cláudia Herrera
CH
Tambeli
D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D001262:Atenolol / Q000494:pharmacology; D002465:Cell Movement / Q000187:drug effects; D005157:Facial Pain / Q000139:chemically induced* / Q000378:metabolism; D007213:Indomethacin / Q000494:pharmacology; D018836:Inflammation Mediators / Q000378:metabolism*; D007267:Injections; D008297:Male; D009619:Nociceptors / Q000187:drug effects*; D010147:Pain Measurement / Q000187:drug effects; D009195:Peroxidase / Q000378:metabolism; D011134:Polysaccharides / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011943:Receptors, Adrenergic, beta / Q000187:drug effects; D012701:Serotonin / Q000494:pharmacology*; D013564:Sympathetic Nervous System / Q000503:physiopathology; D013704:Temporomandibular Joint; D013705:Temporomandibular Joint Disorders / Q000139:chemically induced* / Q000378:metabolism
D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D000894:Anti-Inflammatory Agents, Non-Steroidal; D018836:Inflammation Mediators; D011134:Polysaccharides; D011943:Receptors, Adrenergic, beta; D012701:Serotonin; D001262:Atenolol; C007789:fucoidan; D009195:Peroxidase; D007213:Indomethacin