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Evidence for the involvement of endogenous ATP and P2X receptors in TMJ pain
Author(s) -
Oliveira Maria Cláudia G.,
Parada Carlos Amílcar,
Veiga Maria Cecília Ferraz Arruda,
Rodrigues Luciane Rocha,
Barros Silvana Pereira,
Tambeli Cláudia Herrera
Publication year - 2005
Publication title -
european journal of pain
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.305
H-Index - 109
eISSN - 1532-2149
pISSN - 1090-3801
DOI - 10.1016/j.ejpain.2004.04.006
Subject(s) - endogeny , receptor , neuroscience , medicine , psychology
Evidence is accumulating which supports a role for ATP in the initiation of pain by acting on P2X receptors expressed on nociceptive afferent nerve terminals. To investigate whether these receptors play a role in temporomandibular (TMJ) pain, we studied the presence of functional P2X receptors in rat TMJ by examining the nociceptive behavioral response to the application of the selective P2X receptor agonist α,β‐methylene ATP (α,β‐meATP) into the TMJ region of rat. The involvement of endogenous ATP in the development of TMJ inflammatory hyperalgesia was also determined by evaluating the effect of the general P2 receptor antagonist pyridoxal‐phosphate‐6‐azophenyl‐2′,4′‐disulphonic acid (PPADS) on carrageenan‐induced TMJ inflammatory hyperalgesia. Application of α,β‐meATP into the TMJ region of rats produced significant nociceptive responses that were significantly reduced by the co‐application of lidocaine N ‐ethyl bromide quaternary salt, QX‐314, (2%) or of the P2 receptor antagonist PPADS. Co‐application of PPADS with carrageenan into the TMJ significantly reduced inflammatory hyperalgesia. The results indicate that functional P2X receptors are present in the TMJ and suggest that endogenous ATP may play a role in TMJ inflammatory pain mechanisms possibly by acting primarily in these receptors.