title: Ghrelin Is an Essential Factor for Motilin-Induced Gastric Contraction in Suncus murinus.
abstract: Motilin was discovered in the 1970s as the most important hormone for stimulating strong gastric contractions; however, the mechanisms by which motilin causes gastric contraction are not clearly understood. Here, we determined the coordinated action of motilin and ghrelin on gastric motility during fasted and postprandial contractions by using house musk shrew (Suncus murinus; order: Insectivora, suncus named as the laboratory strain). Motilin-induced gastric contractions at phases I and II of the migrating motor complex were inhibited by pretreatment with (D-Lys(3))-GHRP-6 (6 mg/kg/h), a ghrelin receptor antagonist. Administration of the motilin receptor antagonist MA-2029 (0.1 mg/kg) and/or (D-Lys(3))-GHRP-6 (0.6 mg/kg) at the peak of phase III abolished the spontaneous gastric phase III contractions in vivo. Motilin did not stimulate gastric contractions in the postprandial state. However, in the presence of a low dose of ghrelin, motilin evoked phase III-like gastric contractions even in the postprandial state, and postprandial gastric emptying was accelerated. In addition, pretreatment with (D-Lys(3))-GHRP-6 blocked the motilin-induced gastric contraction in vitro and in vivo, and a γ-aminobutyric acid (GABA) antagonist reversed this block in gastric contraction. These results indicate that blockade of the GABAergic pathway by ghrelin is essential for motilin-induced gastric contraction.
authors.affiliation: Area of Regulatory Biology (K.K., H.H., A.M., M.Y., K.I., T.M., S.T., I.S., T.S.), Division of Life Science, Graduate School of Science and Engineering, Saitama University, Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan; and Laboratory of Animal Management and Resources (T.J.), Department of Zoology, Okayama University of Science, Okayama 700-0005, Japan.
authors.forename: Kayuri
authors.initials: K
authors.lastname: Kuroda
authors.affiliation: Area of Regulatory Biology (K.K., H.H., A.M., M.Y., K.I., T.M., S.T., I.S., T.S.), Division of Life Science, Graduate School of Science and Engineering, Saitama University, Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan; and Laboratory of Animal Management and Resources (T.J.), Department of Zoology, Okayama University of Science, Okayama 700-0005, Japan.
authors.forename: Huang
authors.initials: H
authors.lastname: Hequing
authors.affiliation: Area of Regulatory Biology (K.K., H.H., A.M., M.Y., K.I., T.M., S.T., I.S., T.S.), Division of Life Science, Graduate School of Science and Engineering, Saitama University, Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan; and Laboratory of Animal Management and Resources (T.J.), Department of Zoology, Okayama University of Science, Okayama 700-0005, Japan.
authors.forename: Anupom
authors.initials: A
authors.lastname: Mondal
authors.affiliation: Area of Regulatory Biology (K.K., H.H., A.M., M.Y., K.I., T.M., S.T., I.S., T.S.), Division of Life Science, Graduate School of Science and Engineering, Saitama University, Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan; and Laboratory of Animal Management and Resources (T.J.), Department of Zoology, Okayama University of Science, Okayama 700-0005, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Yoshimura
authors.affiliation: Area of Regulatory Biology (K.K., H.H., A.M., M.Y., K.I., T.M., S.T., I.S., T.S.), Division of Life Science, Graduate School of Science and Engineering, Saitama University, Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan; and Laboratory of Animal Management and Resources (T.J.), Department of Zoology, Okayama University of Science, Okayama 700-0005, Japan.
authors.forename: Kazuma
authors.initials: K
authors.lastname: Ito
authors.affiliation: Area of Regulatory Biology (K.K., H.H., A.M., M.Y., K.I., T.M., S.T., I.S., T.S.), Division of Life Science, Graduate School of Science and Engineering, Saitama University, Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan; and Laboratory of Animal Management and Resources (T.J.), Department of Zoology, Okayama University of Science, Okayama 700-0005, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Mikami
authors.affiliation: Area of Regulatory Biology (K.K., H.H., A.M., M.Y., K.I., T.M., S.T., I.S., T.S.), Division of Life Science, Graduate School of Science and Engineering, Saitama University, Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan; and Laboratory of Animal Management and Resources (T.J.), Department of Zoology, Okayama University of Science, Okayama 700-0005, Japan.
authors.forename: Shota
authors.initials: S
authors.lastname: Takemi
authors.affiliation: Area of Regulatory Biology (K.K., H.H., A.M., M.Y., K.I., T.M., S.T., I.S., T.S.), Division of Life Science, Graduate School of Science and Engineering, Saitama University, Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan; and Laboratory of Animal Management and Resources (T.J.), Department of Zoology, Okayama University of Science, Okayama 700-0005, Japan.
authors.forename: Takamichi
authors.initials: T
authors.lastname: Jogahara
authors.affiliation: Area of Regulatory Biology (K.K., H.H., A.M., M.Y., K.I., T.M., S.T., I.S., T.S.), Division of Life Science, Graduate School of Science and Engineering, Saitama University, Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan; and Laboratory of Animal Management and Resources (T.J.), Department of Zoology, Okayama University of Science, Okayama 700-0005, Japan.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Sakata
authors.affiliation: Area of Regulatory Biology (K.K., H.H., A.M., M.Y., K.I., T.M., S.T., I.S., T.S.), Division of Life Science, Graduate School of Science and Engineering, Saitama University, Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan; and Laboratory of Animal Management and Resources (T.J.), Department of Zoology, Okayama University of Science, Okayama 700-0005, Japan.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Sakai
mesh_terms: D000818:Animals; D005215:Fasting; D005260:Female; D005746:Gastric Emptying / Q000187:drug effects; D054439:Ghrelin / Q000494:pharmacology*; D008297:Male; D009037:Motilin / Q000494:pharmacology*; D009119:Muscle Contraction / Q000187:drug effects*; D016065:Myoelectric Complex, Migrating / Q000187:drug effects*; D009842:Oligopeptides / Q000494:pharmacology; D019518:Postprandial Period; D011964:Receptors, Gastrointestinal Hormone / Q000037:antagonists & inhibitors; D054440:Receptors, Ghrelin / Q000037:antagonists & inhibitors; D018013:Receptors, Neuropeptide / Q000037:antagonists & inhibitors; D012788:Shrews; D013270:Stomach / Q000187:drug effects*
chemical_list: C520836:GHRP-6, Lys(3)-; D054439:Ghrelin; C528741:MA-2029; D009842:Oligopeptides; D011964:Receptors, Gastrointestinal Hormone; D054440:Receptors, Ghrelin; D018013:Receptors, Neuropeptide; C050802:motilin receptor; D009037:Motilin