Upregulation of the Purinergic Receptor Subtype P2X3 in the Trigeminal Ganglion Is Involved in Orofacial Pain Induced by Occlusal Interference in Rats

Aims: To evaluate whether the purinergic receptor subtype P2X3 (P2X3R) in trigeminal ganglion (TG) neurons is involved in hyperalgesia of the temporomandibular joints (TMJs) and masseter muscles associated with placement of an occlusal interference. Methods: Forty-five rats were randomized into five groups (ie, for days 1, 3, 7, 14, or 28; nine rats per group). Six rats from each group were chosen to receive the occlusal interference, and the remaining three rats were sham-treated controls. On days 1, 3, 7, 14, and 28 after placement of the occlusal interference, the mechanical pain threshold (MPT) to stimulation of the TMJs or masseter muscles was examined using von Frey filaments. Seven days after the occlusal interference placement, changes in MPT were tested after administration of the P2X3R antagonist A-317491 into the TMJs and masseter muscles (60 μg/site) in six rats. The expression of P2X3R in the TGs was investigated by immunohistochemistry and quantitative polymerase chain reaction (qPCR). Retrograde tracing was combined with immunofluorescence to identify TMJ and masseter muscle afferent neurons in the TGs of six premature rats. Results: The TMJ and masseter muscle MPTs were decreased after placement of the occlusal interference, and the P2X3R antagonist reversed the mechanical hyperalgesia that was caused by the occlusal interference placement. The frequency of P2X3R-immunoreactive cells increased in small-sized neurons in the TG after occlusal interference. By contrast, there was no increase in medium-sized TG neurons. P2X3R mRNA increased on day 3. Retrograde tracing indicated that the TMJ and masseter muscle afferent neurons in the TG expressed P2X3R. Conclusion: Upregulated P2X3R expression in the TG may contribute to orofacial pain development induced by an occlusal interference. P2X3R may be a therapeutic target for chronic TMJ or masseter muscle pain.

masseter muscle; occlusal interference; orofacial hyperalgesia; P2X3 receptor; temporomandibular joint

1. LeResche L. Epidemiology of temporomandibular disorders: Implications for the investigation of etiologic factors. Crit Rev Oral Biol Med 1997;8:291–305.

2. Kirveskari P, Alanen P, Jämsä T. Association between craniomandibular disorders and occlusal interferences in children. J Prosthet Dent 1992;67:692–696.

3. Pullinger AG, Seligman DA, Gornbein JA. A multiple logistic regression analysis of the risk and relative odds of temporomandibular disorders as a function of common occlusal features. J Dent Res 1993;72:968–979.

4. Jennings EA, Williams MC, Staikopoulos V, Ivanusic JJ. Neurobiology of temporomandibular joint pain: Therapeutic implications. Semin Orthod 2012;18:63–72.

5. Chizh BA, Illes P. P2X receptors and nociception. Pharmacol Rev 2001;53:553–568.

6. Bleehen T, Keele CA. Observations on the algogenic actions of adenosine compounds on the human blister base preparation. Pain 1977;3:367–377.

7. Hamilton SG, Warburton J, Bhattacharjee A, Ward J, McMahon SB. ATP in human skin elicits a dose-related pain response which is potentiated under conditions of hyperalgesia. Brain 2000; 123:1238–1246.

8. North RA. P2X3 receptors and peripheral pain mechanisms. J Physiol 2004;554:301–308.

9. Staikopoulos V, Sessle BJ, Furness JB, Jennings EA. Localization of P2X2 and P2X3 receptors in rat trigeminal ganglion neurons. Neuroscience 2007;144:208–216.

10. Ichikawa H, Fukunaga T, Jin HW, Fujita M, Takano-Yamamoto T, Sugimoto T. VR1-, VRL-1- and P2X3 receptor-immunoreactive innervation of the rat temporomandibular joint. Brain Res 2004; 1008:131–136.

11. Shinoda M, Ozaki N, Asai H, Nagamine K, Sugiura Y. Changes in P2X3 receptor expression in the trigeminal ganglion following monoarthritis of the temporomandibular joint in rats. Pain 2005;116:42–51.

12. Shinoda M, Ozaki N, Sugiura Y. Involvement of ATP and its receptors on nociception in rat model of masseter muscle pain. Pain 2008;134:148–157.

13. Teixeira JM, Oliveira MC, Nociti FH Jr, et al. Involvement of temporomandibular joint P2X3 and P2X2/3 receptors in carrageenan-induced inflammatory hyperalgesia in rats. Eur J Pharmacol 2010;645:79–85.

14. Cao Y, Xie QF, Li K, Light AR, Fu KY. Experimental occlusal interference induces long-term masticatory muscle hyperalgesia in rats. Pain 2009;144:287–293.

15. Ogawa A, Ren K, Tsuboi Y, Morimoto T, Sato T, Iwata K. A new model of experimental parotitis in rats and its implication for trigeminal nociception. Exp Brain Res 2003;152:307–316.

16. Ren K. An improved method for assessing mechanical allodynia in the rat. Physiol Behav 1999;67:711–716.

17. Liu XD, Wang XD, Sun L, Zhang M, Fu KY. An animal model of masticatory muscle hyperalgesia induced by experimental individual molar movement in rats. Chin J Conserv Dent 2005;15: 542–545.

18. Wu G, Whiteside GT, Lee G, et al. A-317491, a selective P2X3/P2X2/3 receptor antagonist, reverses inflammatory mechanical hyperalgesia through action at peripheral receptors in rats. Eur J Pharmacol 2004;504:45–53.

19. Hwang IK, Lee HY, Yoo KY, et al. Chronological alterations of P2X3 receptor expression in the trigeminal ganglion after ischaemic insult in the Mongolian gerbil. Anat Histol Embryol 2004; 33:220–224.

20. Nishide N, Baba S, Hori N, Nishikawa H. Histological study of rat masseter muscle following experimental occlusal alteration. J Oral Rehabil 2001;28:294–298.

21. Schmidt-Hansen PT, Svensson P, Jensen TS, Graven-Nielsen T, Bach FW. Patterns of experimentally induced pain in pericranial muscles. Cephalalgia 2006;26:568–577.

22. Xie Q, Li X, Xu X. The difficult relationship between occlusal interferences and temporomandibular disorder—insights from animal and human experimental studies. J Oral Rehabil 2013; 40:279–295.

23. Ekberg E, Vallon D, Nilner M. The efficacy of appliance therapy in patients with temporomandibular disorders of mainly myogenous origin. A randomized, controlled, short-term trial. J Orofac Pain 2003;17:133–139.

24. Kurita H, Ohtsuka A, Kurashina K, Kopp S. A study of factors for successful splint capture of anteriorly displaced temporomandibular joint disc with disc repositioning appliance. J Oral Rehabil 2001;28:651–657.

25. De Boever JA, Carlsson GE, Klineberg IJ. Need for occlusal therapy and prosthodontic treatment in the management of temporomandibular disorders. Part II: Tooth loss and prosthodontic treatment. J Oral Rehabil 2000;27:647–659.

26. Sadowsky C, Theisen TA, Sakols EI. Orthodontic treatment and temporomandibular joint sounds—A longitudinal study. Am J Orthod Dentofacial Orthop 1991;99:441–447.

27. Egermark I, Blomqvist JE, Cromvik U, Isaksson S. Temporomandibular dysfunction in patients treated with orthodontics in combination with orthognathic surgery. Eur J Orthod 2000; 22:537–544.

28. Le Resche L, Truelove EL, Dworkin SF. Temporomandibular disorders: A survey of dentists’ knowledge and beliefs. J Am Dent Assoc 1993;124:90–94,97–106.

29. Glaros AG, Glass EG, McLaughlin L. Knowledge and beliefs of dentists regarding temporomandibular disorders and chronicpain. J Orofac Pain 1994;8:216–222.

30. Arbree NS, Campbell SD, Renner RP, Goldstein GR. A survey of temporomandibular disorder conducted by the Greater New York Academy of Prosthodontics. J Prosthet Dent 1995; 74:512–516.

31. Stahl SS, Miller SC, Goldsmith ED. The influence of occlusal trauma and protein deprivation on the response of periapical tissues following pulpal exposures in rats. Oral Surg Oral Med Oral Pathol 1958;11:536–540.

32. Akagawa Y, Nikai H, Tsuru H. Histologic changes in rat masticatory muscles subsequent to experimental increase of the occlusal vertical dimension. J Prosthet Dent 1983;50:725–732.

33. Chen J, Zhang J, Zhao Y, et al. Hyperalgesia in response to traumatic occlusion and GFAP expression in rat parabrachial [correction of parabranchial] nucleus: Modulation with fluorocitrate. Cell Tissue Res 2007;329:231–237.

34. Li J, Jiang T, Feng H, Wang K, Zhang Z, Ishikawa T. The electromyographic activity of masseter and anterior temporalis during orofacial symptoms induced by experimental occlusal highspot. J Oral Rehabil 2008;35:79–87.

35. North RA. Molecular physiology of P2X receptors. Physiol Rev 2002;82:1013–1067.

36. Burnstock G. P2X receptors in sensory neurones. Br J Anaesth 2000;84:476–488.

37. Khakh BS. Molecular physiology of P2X receptors and ATP signalling at synapses. Nat Rev Neurosci 2001;2:165–174.

38. Hsieh YL, Chiang H, Lue JH, Hsieh ST. P2X3-mediated peripheral sensitization of neuropathic pain in resiniferatoxin-induced neuropathy. Exp Neurol 2012;235:316–325.

39. Hu B, Chiang CY, Hu JW, Dostrovsky JO, Sessle BJ. P2X receptors in trigeminal subnucleus caudalis modulate central sensitization in trigeminal subnucleus oralis. J Neurophysiol 2002;88: 1614–1624.

40. Chiang CY, Zhang S, Xie YF, et al. Endogenous ATP involvement in mustard-oil-induced central sensitization in trigeminal subnucleus caudalis (medullary dorsal horn). J Neurophysiol 2005; 94:1751–1760.

41. Jennings EA, Christie MJ, Sessle BJ. ATP potentiates neurotransmission in the rat trigeminal subnucleus caudalis. Neuroreport 2006;17:1507–1510.