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Role of TRPV 1 and ASIC 3 channels in experimental occlusal interference‐induced hyperalgesia in rat masseter muscle
Author(s) -
Xu X.X.,
Cao Y.,
Ding T.T.,
Fu K.Y.,
Li Y.,
Xie Q.F.
Publication year - 2016
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 - 10.1002/ejp.758
Subject(s) - trpv1 , hyperalgesia , masseter muscle , chemistry , transient receptor potential channel , antagonist , medicine , anatomy , endocrinology , nociception , receptor
Background Masticatory muscle pain may occur following immediate occlusal alteration by dental treatment. The underlying mechanisms are poorly understood. Transient receptor potential vanilloid‐1 ( TRPV 1) and acid‐sensing ion channel‐3 ( ASIC 3) mediate muscle hyperalgesia under various pathologic conditions. We have developed a rat model of experimental occlusal interference ( EOI ) that consistently induces mechanical hyperalgesia in jaw muscles. Whether TRPV 1 and ASIC 3 mediate this EOI ‐induced hyperalgesia is unknown. Methods Rat model of EOI ‐induced masseter hyperalgesia was established. Real‐time polymerase chain reaction, Western blot and retrograde labelling combined with immunofluorescence were performed to evaluate the modulation of TRPV 1 and ASIC 3 expression in trigeminal ganglia ( TG s) and masseter afferents of rats after EOI . The effects of intramuscular administration of TRPV 1 and ASIC 3 antagonists on the EOI ‐induced hyperalgesia in masseter muscle were examined. Results After EOI , gene expressions and protein levels of TRPV 1 and ASIC 3 in bilateral TG s were up‐regulated. The percentage of ASIC 3‐ (but not TRPV 1‐) positive neurons in masseter afferents increased after EOI . More small‐sized and small to medium‐sized masseter afferents expressed TRPV 1 and ASIC 3 separately following EOI . These changes peaked at day 7 and then returned to original status within 10 days after EOI . Intramuscular administration of the TRPV 1 antagonist AMG ‐9810 partially reversed this mechanical hyperalgesia in masseter muscle. No improvement was exhibited after administration of the ASIC 3 antagonist APET x2. Co‐injection of AMG ‐9810 and APET x2 enhanced the effect of AMG ‐9810 administration alone. Conclusions Peripheral TRPV 1 and ASIC 3 contribute to the development of the EOI ‐induced mechanical hyperalgesia in masseter muscle.