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TRPA1‐activated anion secretion is linked with PGE2 receptor EP4 in human and rat colon
Author(s) -
Kaji Izumi,
Karaki Shin-ichiro,
Kuwahara Atsukazu
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.1154.1
Subject(s) - allyl isothiocyanate , secretion , ussing chamber , chemistry , agonist , transient receptor potential channel , extracellular , receptor , cyclooxygenase , medicine , endocrinology , microbiology and biotechnology , pharmacology , biochemistry , biology , enzyme
The transient receptor potential A1 (TRPA1) channel is considered a chemosensor in several sensory tissues. In the present study, we investigated the secretory effect of potential TRPA1 agonist allyl isothiocyanate (AITC) in rat and human colons using the Ussing flux chamber. The mucosal application of AITC (10 −6 –10 −3 M) induced Cl − and HCO 3 − secretion in a concentration‐dependent manner, while the serosal application induced weaker effect. AITC‐evoked anion secretion was attenuated by the pretreatment with cyclooxygenase inhibitor piroxicam and prostaglandin (PG) E 2 , but the secretion was not affected by tetrodotoxin, atropine, or extracellular Ca 2+ depletion. These results indicated that TRPA1 activation induces anion secretion through PG synthesis independent of neural pathway in the colon. Further analysis also indicated that AITC‐evoked anion secretion is mainly mediated by EP 4 . In addition, RT‐PCR using isolated colonic crypts, in situ hybridization and immunohistochemistry supported the TRPA1 expression in epithelial cells. Therefore, we conclude that the activation of TRPA1 activity on the colonic epithelial cells is likely involved in host defense mechanism through rapid anion secretion.