title: Trypsin induces biphasic muscle contraction and relaxation via transient receptor potential vanilloid 1 and neurokinin receptors 1/2 in porcine esophageal body.
abstract: Duodenal reflux of fluids containing trypsin relates to refractory gastroesophageal reflux disease (GERD). Esophageal peristalsis and clearance are important factors in GERD pathogenesis. However, the function of trypsin in esophageal body contractility is not fully understood. In this study, effects of trypsin on circular smooth muscle (CSM) and longitudinal smooth muscle (LSM) of the porcine esophageal body were examined. Trypsin elicited a concentration dependent biphasic response, a major contraction and a subsequent relaxation only in CSM. In CSM, contraction occurred at trypsin concentrations of 100nM and relaxation at 1μM. A proteinase-activated receptor (PAR)2 activating peptide, SLIGKV-NH2(1mM), induced a monophasic contraction. Those responses were unaffected by tetrodotoxin though abolished by the gap junction uncouplers carbenoxolone and octanol. They were also partially inhibited by a transient receptor potential vanilloid type 1 (TRPV1) antagonist and abolished by combination of neurokinin receptor 1 (NK1) and NK2antagonists, but not by an NK3antagonist, suggesting a PAR2-TRPV1-substance P pathway in sensory neurons. Substance P (100nM), an agonist for various NK receptors (NK1, NK2and NK3) with differing affinities, induced significant contraction in CSM, but not in LSM. The contraction was also blocked by the combination of NK1and NK2antagonists, but not by the NK3antagonist. Moreover, substance P-induced contractions were unaffected by the TRPV1 antagonist, but inhibited by a gap junction uncoupler. In conclusion, trypsin induced a biphasic response only in CSM and this was mediated by PAR2, TRPV1 and NK1/2. Gap junctions were indispensable in this tachykinin-induced response.
authors.affiliation: Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
authors.forename: Bai
authors.initials: B
authors.lastname: Xiaopeng
authors.affiliation: Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Tanaka
authors.affiliation: Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan. Electronic address: eikichi@intmed3.med.kyushu-u.ac.jp.
authors.forename: Eikichi
authors.initials: E
authors.lastname: Ihara
authors.affiliation: Department of Cardiovascular Physiology, Faculty of Medicine, Kagawa University, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa Prefecture 761-0793, Japan.
authors.forename: Katsuya
authors.initials: K
authors.lastname: Hirano
authors.affiliation: Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
authors.forename: Kayoko
authors.initials: K
authors.lastname: Nakano
authors.affiliation: Division of Molecular Cardiology, Research Institute of Angiocardiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
authors.forename: Mayumi
authors.initials: M
authors.lastname: Hirano
authors.affiliation: Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
authors.forename: Yoshinao
authors.initials: Y
authors.lastname: Oda
authors.affiliation: Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Nakamura
mesh_terms: D000818:Animals; D011464:Epoprostenol / Q000378:metabolism; D004947:Esophagus / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects* / Q000502:physiology; D009569:Nitric Oxide / Q000378:metabolism; D018040:Receptors, Neurokinin-1 / Q000378:metabolism*; D018041:Receptors, Neurokinin-2 / Q000378:metabolism*; D013552:Swine; D050916:TRPV Cation Channels / Q000378:metabolism*; D014357:Trypsin / Q000494:pharmacology*; D054460:rho-Associated Kinases / Q000378:metabolism
chemical_list: D018040:Receptors, Neurokinin-1; D018041:Receptors, Neurokinin-2; D050916:TRPV Cation Channels; C493921:TRPV1 protein, mouse; D009569:Nitric Oxide; D011464:Epoprostenol; D054460:rho-Associated Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D014357:Trypsin
keywords: Esophageal motility; Neurokinin receptors; Proteinase-activated receptors; Substance P; Transient receptor potential vanilloid type 1; Trypsin