title: Trypsin-induced biphasic regulation of tone in the porcine lower esophageal sphincter.
abstract: The lower esophageal sphincter (LES) plays an important role in coordinated esophageal motility. The present study aimed to elucidate how trypsin affects LES contractility. Porcine LES circular smooth muscle strips were prepared. Contractile responses to trypsin were assessed. Trypsin (300nM) induced a transient contraction. At concentrations of 1μM or higher, trypsin induced biphasic responses, consisting of a transient contraction followed by a transient relaxation. Pretreatment with either 1μM tetrodotoxin or carbenoxolone had no effect on these responses. In contrast, trypsin-induced responses were completely blocked by pretreatment with the serine protease inhibitor. Pretreatment with 10μM FSLLRY-NH2, a PAR2 antagonist, significantly inhibited trypsin-induced biphasic responses. Trypsin (1μM)-induced contractions were partially inhibited by pretreatment with 10μM Y-27632. In addition, trypsin (10μM)-induced relaxation was partially inhibited by pretreatment with 10μM Y-27632, 10μM PD98059 or 10μM SB203580. Trypsin-induced relaxation was abolished by increasing the extracellular K(+) concentration to 40mM, but not by pretreatment with l-arginine methyl ester. Furthermore, trypsin-induced relaxation was partially inhibited by pretreatment with 10μM glibenclamide or 1μM 4-aminopyridine. Trypsin causes biphasic regulation of LES tone by directly acting on smooth muscle. Rho-associated protein kinase (ROK) is involved in trypsin-induced contraction, whereas ROK, ERK1/2, p38MAPK, and membrane hyperpolarization are involved in relaxation. The regulation of LES tone by trypsin may play a role in esophageal motility.
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: 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: 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: Shunsuke
authors.initials: S
authors.lastname: Takahashi
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 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
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: Hirotada
authors.initials: H
authors.lastname: Akiho
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: Ryoichi
authors.initials: R
authors.lastname: Takayanagi
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D049630:Esophageal Sphincter, Lower / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors; D009119:Muscle Contraction / Q000187:drug effects*; D009126:Muscle Relaxation / Q000187:drug effects*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D044464:Receptor, PAR-2 / Q000378:metabolism; D013552:Swine; D014357:Trypsin / Q000494:pharmacology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D047428:Protein Kinase Inhibitors; D044464:Receptor, PAR-2; D054460:rho-Associated Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048051:p38 Mitogen-Activated Protein Kinases; D014357:Trypsin
keywords: Esophageal motility; Gastro-esophageal reflux disease; Proteinase-activated receptors; Smooth muscle; Trypsin