title: Contractile effect of TRPA1 receptor agonists in the isolated mouse intestine.
abstract: TRPA1 is a member of the transient receptor potential (TRP) channel family expressed in sensory neurons. The present study focused on the effects of TRPA1 activation on contractile responses in isolated mouse intestine preparations. The jejunum, ileum, and proximal and distal colon were surgically isolated from male ddY mice. Intestinal motility was recorded as changes in isotonic tension. TRPA1, TRPM8, and TRPV1 expressions were examined by reverse transcription-polymerase chain reaction (RT-PCR). A TRPA1 agonist allyl isothiocyanate (AITC) dose-dependently induced contractions in the proximal and distal colon, whereas in the jejunum and ileum, even 100 muM AITC caused very little contraction. Likewise, a TRPA1 and TRPM8 agonist icilin, a TRPA1 agonist allicin, and a TRPV1 agonist capsaicin induced contractions in the colon. However, a TRPM8 agonist menthol induced long-lasting relaxation in the colon. Repeated exposure to AITC produced desensitization of its own contraction in the colon. Moreover, contractions induced by AITC generate cross-desensitization with icilin and capsaicin. Tetrodotoxin completely abolished AITC-induced contractions in the colon, whereas atropine significantly attenuated AITC-induced contractions in the distal colon, but not in the proximal colon. Menthol-induced relaxation in the colon was not inhibited by tetrodotoxin and atropine. RT-PCR analysis revealed the expression of TRPA1 and TRPV1, but not TRPM8, throughout the mouse intestine. These results suggest that TRPA1, but not TRPM8, are functionally expressed in the enteric nervous system throughout the mouse intestine on neurons that may also co-express TRPV1, yet the contractile responses to TRPA1 activation differ depending on their location along the intestine.
authors.affiliation: Department of Molecular Pharmacology and Pharmacotherapeutics, Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8675, Japan.
authors.forename: Angelica
authors.initials: A
authors.lastname: Penuelas
authors.forename: Kimihito
authors.initials: K
authors.lastname: Tashima
authors.forename: Shizuko
authors.initials: S
authors.lastname: Tsuchiya
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Tomonori
authors.initials: T
authors.lastname: Nakamura
authors.forename: Syunji
authors.initials: S
authors.lastname: Horie
authors.forename: Shingo
authors.initials: S
authors.lastname: Yano
mesh_terms: D000818:Animals; D002211:Capsaicin / Q000494:pharmacology; D004220:Disulfides; D005769:Gastrointestinal Motility / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D007422:Intestines / Q000187:drug effects / Q000502:physiology*; D017879:Isothiocyanates / Q000494:pharmacology; D008297:Male; D008610:Menthol / Q000494:pharmacology; D051379:Mice; D011744:Pyrimidinones / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D013441:Sulfinic Acids / Q000494:pharmacology; D000074025:TRPA1 Cation Channel; D050053:TRPM Cation Channels / Q000235:genetics / Q000502:physiology; D050916:TRPV Cation Channels / Q000235:genetics / Q000502:physiology; D050051:Transient Receptor Potential Channels / Q000819:agonists* / Q000235:genetics / Q000502:physiology*