title: Involvement of TRPV1 and TRPA1 in incisional intraoral and extraoral pain.
abstract: Thermal and mechanical hypersensitivity in the injured region is a common complication. Although it is well known clinically that thermal and mechanical sensitivity of the oral mucosa is different from that of the skin, the mechanisms underlying injured pain of the oral mucosa remain poorly understood. The transient receptor potential (TRP) vanilloid 1 (TRPV1) and TRP ankyrin 1 (TRPA1) in primary afferent neurons are known to contribute to pathological pain. Therefore, we investigated whether TRPV1 and/or TRPA1 contribute to thermal and mechanical hypersensitivity following oral mucosa or whisker pad skin incision. Strong heat and mechanical and cold hypersensitivity was caused in the buccal mucosa and whisker pad skin following incisions. On day 3 after the incisions, the number of TRPV1-immunoreactive (IR) and TRPA1-IR trigeminal ganglion (TG) neurons innervating the buccal mucosa and whisker pad skin was significantly increased, and the number of TRPV1/TRPA1-IR TG neurons innervating whisker pad skin, but not the buccal mucosa, was significantly increased. Administration of the TRPV1 antagonist, SB366791, to the incised site produced a significant suppression of heat hyperalgesia in both the buccal mucosa and whisker pad skin, as well as mechanical allodynia in the whisker pad skin. Administration of the TRPA1 antagonist, HC-030031, to the incised site suppressed mechanical allodynia and cold hyperalgesia in both the buccal mucosa and whisker pad skin, as well as heat hyperalgesia in the whisker pad skin. These findings indicate that altered expressions of TRPV1 and TRPA1 in TG neurons are involved in thermal and mechanical hypersensitivity following the buccal mucosa and whisker pad skin incision. Moreover, diverse changes in the number of TRPV1 and TRPA1 coexpressed TG neurons in whisker pad skin-incised rats may contribute to the intracellular interactions of TRPV1 and TRPA1 associated with whisker pad skin incision, whereas TRPV1 and TRPA1 expression in individual TG neurons is involved in buccal mucosa-incised pain.
authors.affiliation: Department of Complete Denture Prosthodontics, Nihon University School of Dentistry, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Urata
authors.affiliation: Department of Physiology, Nihon University School of Dentistry, Tokyo, Japan Division of Functional Morphology, Dental Research Center, Nihon University School of Dentistry, Tokyo, Japan shinoda.masamichi@nihon-u.ac.jp.
authors.forename: M
authors.initials: M
authors.lastname: Shinoda
authors.affiliation: Department of Physiology, Nihon University School of Dentistry, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Honda
authors.affiliation: Department of Complete Denture Prosthodontics, Nihon University School of Dentistry, Tokyo, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Complete Denture Prosthodontics, Nihon University School of Dentistry, Tokyo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Maruno
authors.affiliation: Department of Complete Denture Prosthodontics, Nihon University School of Dentistry, Tokyo, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Ito
authors.affiliation: Department of Complete Denture Prosthodontics, Nihon University School of Dentistry, Tokyo, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Gionhaku
authors.affiliation: Department of Physiology, Nihon University School of Dentistry, Tokyo, Japan Division of Functional Morphology, Dental Research Center, Nihon University School of Dentistry, Tokyo, Japan Division of Applied System Neuroscience Advanced Medical Research Center, Nihon University Graduate School of Medical Science, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Iwata
mesh_terms: D000083:Acetanilides / Q000494:pharmacology; D000813:Anilides / Q000494:pharmacology; D000818:Animals; D002934:Cinnamates / Q000494:pharmacology; D003080:Cold Temperature; D004576:Electromyography / Q000379:methods; D005157:Facial Pain / Q000503:physiopathology*; D006358:Hot Temperature; D006930:Hyperalgesia / Q000503:physiopathology; D008297:Male; D009061:Mouth Mucosa / Q000293:injuries* / Q000294:innervation; D009474:Neurons / Q000166:cytology / Q000502:physiology; D010146:Pain / Q000503:physiopathology*; D011687:Purines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D000074025:TRPA1 Cation Channel; D050052:TRPC Cation Channels / Q000032:analysis / Q000037:antagonists & inhibitors / Q000502:physiology*; D050916:TRPV Cation Channels / Q000032:analysis / Q000037:antagonists & inhibitors / Q000502:physiology*; D012668:Trigeminal Ganglion / Q000503:physiopathology; D014738:Vibrissae / Q000293:injuries / Q000294:innervation
chemical_list: C552888:2-(1,3-dimethyl-2,6-dioxo-1,2,3,6-tetrahydro-7H-purin-7-yl)-N-(4-isopropylphenyl)acetamide; D000083:Acetanilides; D000813:Anilides; D002934:Cinnamates; C477659:N-(3-methoxyphenyl)-4-chlorocinnamanilide; D011687:Purines; D000074025:TRPA1 Cation Channel; D050052:TRPC Cation Channels; D050916:TRPV Cation Channels; C480976:Trpa1 protein, rat; C493922:Trpv1 protein, rat
keywords: mechanical allodynia; mouth mucosa; thermal allodynia; transient receptor potential channels; trigeminal ganglion; whiskers