Peripheral N-methyl-d-aspartate receptors contribute to mechanical hypersensitivity in a rat model of inflammatory temporomandibular joint pain

Abstract

The aim of this study was to determine whether peripheral N-methyl-d-aspartate (NMDA) receptors are involved in inflammation-induced mechanical hypersensitivity of the temporomandibular joint (TMJ) region. We developed a rat model of mechanical sensitivity to Complete Freund's Adjuvant (CFA; 2 μl containing 1 μg Mycobacterium tuberculosis)-induced inflammation of the TMJ and examined changes in sensitivity following injection of NMDA receptor antagonists (dl-2-amino-5-phosphonovaleric acid (AP5) or Ifenprodil) with CFA. CFA injected into the TMJ resulted in an increase in mechanical sensitivity relative to pre-injection that peaked at day 1 and lasted for up to 3 days (n = 8, P < 0.05). Ther..