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Suzuki M, Watanabe A, Huang J, Kobayashi Y, Sakata I. Involvement of the autonomic nervous system in colonic contractions in conscious Suncus murinus. Neurogastroenterol Motil 2024; 36:e14716. [PMID: 38031349 DOI: 10.1111/nmo.14716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 10/06/2023] [Accepted: 11/10/2023] [Indexed: 12/01/2023]
Abstract
BACKGROUND Colonic motility is regulated by various factors along the gut-brain axis; however, detailed mechanisms are unknown. This study aimed to examine the involvement of the autonomic nervous system in colonic motility. Suncus murinus (suncus) is a small laboratory mammal suitable for gastrointestinal motility studies. METHODS Colonic motility and concomitant feeding and defecation behaviors in vagotomized and reserpine-administered suncus were recorded simultaneously for 24 h. Furthermore, we performed immunohistochemistry on tyrosine hydroxylase (TH) and in situ hybridization on corticotropin-releasing hormone (CRH) in suncus brain. Additionally, we examined c-Fos expression in the brain using immunohistochemistry in conscious suncus with colorectal distension. KEY RESULTS In vagotomized suncus, clustered giant migrating contractions (GMCs), consisting of strong contractions occurring in a short time, were observed, and the percentage of GMCs without defecation increased. The frequency of GMCs in the reserpine-administered suncus increased during a light period (ZT0-4, 4-8) and decreased during a dark period (ZT16-20, 20-24) compared to a vehicle group. Additionally, the percentage of GMCs without defecation in the reserpine-administered suncus increased. Suncus TH-immunopositive neurons were found in the locus coeruleus (LC), as shown in rodents. In contrast, CRH mRNA-expressing cells were not observed in a region assumed to be the Barrington's nucleus (Bar). Furthermore, colorectal distension in conscious suncus induced c-Fos expression in LC TH neurons. CONCLUSIONS & INFERENCES Our results suggest that the vagus and sympathetic nerves are not required for induction of GMCs in vivo. However, they are likely to exert a modulatory role in control of GMC frequency in Suncus murinus.
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Affiliation(s)
- Miu Suzuki
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Ayumi Watanabe
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Jin Huang
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Yuki Kobayashi
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Ichiro Sakata
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
- Area of Research Evolutionary Molecular Design, Strategic Research Center, Saitama University, Saitama, Japan
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2
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Clemente-Suárez VJ, Beltrán-Velasco AI, Redondo-Flórez L, Martín-Rodríguez A, Yáñez-Sepúlveda R, Tornero-Aguilera JF. Neuro-Vulnerability in Energy Metabolism Regulation: A Comprehensive Narrative Review. Nutrients 2023; 15:3106. [PMID: 37513524 PMCID: PMC10383861 DOI: 10.3390/nu15143106] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/09/2023] [Accepted: 07/10/2023] [Indexed: 07/30/2023] Open
Abstract
This comprehensive narrative review explores the concept of neuro-vulnerability in energy metabolism regulation and its implications for metabolic disorders. The review highlights the complex interactions among the neural, hormonal, and metabolic pathways involved in the regulation of energy metabolism. The key topics discussed include the role of organs, hormones, and neural circuits in maintaining metabolic balance. The review investigates the association between neuro-vulnerability and metabolic disorders, such as obesity, insulin resistance, and eating disorders, considering genetic, epigenetic, and environmental factors that influence neuro-vulnerability and subsequent metabolic dysregulation. Neuroendocrine interactions and the neural regulation of food intake and energy expenditure are examined, with a focus on the impact of neuro-vulnerability on appetite dysregulation and altered energy expenditure. The role of neuroinflammation in metabolic health and neuro-vulnerability is discussed, emphasizing the bidirectional relationship between metabolic dysregulation and neuroinflammatory processes. This review also evaluates the use of neuroimaging techniques in studying neuro-vulnerability and their potential applications in clinical settings. Furthermore, the association between neuro-vulnerability and eating disorders, as well as its contribution to obesity, is examined. Potential therapeutic interventions targeting neuro-vulnerability, including pharmacological treatments and lifestyle modifications, are reviewed. In conclusion, understanding the concept of neuro-vulnerability in energy metabolism regulation is crucial for addressing metabolic disorders. This review provides valuable insights into the underlying neurobiological mechanisms and their implications for metabolic health. Targeting neuro-vulnerability holds promise for developing innovative strategies in the prevention and treatment of metabolic disorders, ultimately improving metabolic health outcomes.
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Affiliation(s)
- Vicente Javier Clemente-Suárez
- Faculty of Sports Sciences, Universidad Europea de Madrid, Tajo Street, s/n, 28670 Madrid, Spain
- Grupo de Investigación en Cultura, Educación y Sociedad, Universidad de la Costa, Barranquilla 080002, Colombia
| | | | - Laura Redondo-Flórez
- Department of Health Sciences, Faculty of Biomedical and Health Sciences, Universidad Europea de Madrid, Tajo Street s/n, 28670 Madrid, Spain
| | | | - Rodrigo Yáñez-Sepúlveda
- Faculty of Education and Social Sciences, Universidad Andres Bello, Viña del Mar 2520000, Chile
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3
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Wada R, Takemi S, Matsumoto M, Iijima M, Sakai T, Sakata I. Molecular cloning and analysis of the ghrelin/GHSR system in Xenopus tropicalis. Gen Comp Endocrinol 2023; 331:114167. [PMID: 36402245 DOI: 10.1016/j.ygcen.2022.114167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 10/16/2022] [Accepted: 11/12/2022] [Indexed: 11/18/2022]
Abstract
Ghrelin is a gut-derived peptide with several physiological functions, including feeding, gastrointestinal motility, and hormonal secretion. Recently, a host defense peptide, liver-expressed antimicrobial peptide-2 (LEAP2), was reported as an endogenous antagonist of growth hormone secretagogue receptor (GHS-R). The physiological relevance of the molecular LEAP2-GHS-R interaction in mammals has been explored; however, studies on non-mammals are limited. Here, we report the identification and functional characterization of ghrelin and its related molecules in Western clawed frog (Xenopus tropicalis), a known model organism. We first identified cDNA encoding X. tropicalis ghrelin and GHS-R. RT-qPCR revealed that ghrelin mRNA expression was most abundant in the stomach. GHS-R mRNA was widely distributed in the brain and peripheral tissues, and a relatively strong signal was observed in the stomach and intestine. In addition, LEAP2 was mainly expressed in intestinal tissues at higher levels than in the liver. In functional analysis, X. tropicalis ghrelin and human ghrelin induced intracellular Ca2+ mobilization with EC50 values in the low nanomolar range in CHO-K1 cells expressing X. tropicalis GHS-R. Furthermore, ghrelin-induced GHS-R activation was antagonized with IC50 values in the nanomolar range by heterologous human LEAP2. We also validated the expression of ghrelin and feeding-related factors under fasting conditions. After 2 days of fasting, no changes in ghrelin mRNA levels were observed in the stomach, but GHS-R mRNA levels were significantly increased, associated with significant downregulation of nucb2. In addition, LEAP2 upregulation was observed in the duodenum. These results provide the first evidence that LEAP2 functions as an antagonist of GHS-R in the anuran amphibian X. tropicalis. It has also been suggested that the ghrelin/GHS-R/LEAP2 system may be involved in energy homeostasis in X. tropicalis.
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Affiliation(s)
- Reiko Wada
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan
| | - Shota Takemi
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan
| | - Mio Matsumoto
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan
| | - Mio Iijima
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan
| | - Takafumi Sakai
- Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama 338-8570, Japan
| | - Ichiro Sakata
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan.
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4
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Takemi S, Honda W, Yokota N, Sekiya H, Miura T, Wada R, Sakai T, Sakata I. Molecular cloning of cholecystokinin (CCK) and CCK-A receptor and mechanism of CCK-induced gastrointestinal motility in Suncus murinus. Gen Comp Endocrinol 2022; 327:114074. [PMID: 35700795 DOI: 10.1016/j.ygcen.2022.114074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 06/02/2022] [Accepted: 06/09/2022] [Indexed: 11/25/2022]
Abstract
Cholecystokinin (CCK) is a peptide hormone mainly secreted by small intestinal endocrine I-cells and functions as a regulator of gallbladder contraction, gastric emptying, gastrointestinal (GI) motility, and satiety. The cellular effects of CCK in these peripheral tissues are predominantly mediated via CCK-A receptors which are found in smooth muscles, enteric neurons, and vagal afferent neurons in humans and animal models. Although various functions of CCK have been reported to be neurally mediated, it can also stimulate contraction via the CCK receptor on the smooth muscle. However, the entire underlying neural and cellular mechanisms involved in CCK-induced GI contractions are not clearly understood. Here, we first determined the cDNA and amino acid sequences of CCK and CCK-A receptor along with the distributions of cck mRNA and CCK-producing cells in house musk shrew (Suncus murinus, the laboratory strain named as suncus) and examined the mechanism of CCK-induced contraction in the GI tract. Mature suncus CCK-8 was identical to other mammalian species tested here, and suncus CCK-A receptor presented high nucleotide and amino acid homology with that of human, dog, mouse, and rat, respectively. Suncus CCK mRNA and CCK-producing cells were found mainly in small intestine and colon. In the organ bath study, CCK-8 induced dose-dependent contractions in the suncus stomach, duodenum, and jejunum, and these contractions were inhibited by atropine and CCK-A receptor antagonist. These results suggest that CCK-8-induced contraction is mediated in the myenteric cholinergic neural network and that CCK-A receptor is partly responsible for CCK-8-induced contractions. This study indicates that suncus is a useful animal model to study the functions of CCK involved in GI motility.
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Affiliation(s)
- Shota Takemi
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan
| | - Wataru Honda
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan
| | - Naho Yokota
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan
| | - Haruka Sekiya
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan
| | - Takashi Miura
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan
| | - Reiko Wada
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan
| | - Takafumi Sakai
- Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan
| | - Ichiro Sakata
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan; Area of Life-NanoBio, Division of Strategy Research, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan
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5
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Kobayashi Y, Takemi S, Sakai T, Shibata C, Sakata I. Diurnal changes of colonic motility and regulatory factors for colonic motility in Suncus murinus. Neurogastroenterol Motil 2022; 34:e14302. [PMID: 34846085 DOI: 10.1111/nmo.14302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 11/02/2021] [Accepted: 11/10/2021] [Indexed: 02/08/2023]
Abstract
BACKGROUND The aim of this study was to investigate the fundamental mechanisms of colonic motility in the house musk suncus (Suncus murinus) as an established animal model of gut motility. METHODS To measure gut motility in free-moving conscious suncus, strain gauge force transducers were implanted on the serosa of the colon and gastric body. KEY RESULTS We recorded diurnal changes in colonic motility and observed the relationship between feeding and colonic motility. Giant migrating contractions (GMCs) of the colon were invariably detected during defecation and tended to increase during the dark period, thereby indicating that colonic motility has a circadian rhythm. Given that GMCs in the suncus were observed immediately after feeding during the dark period, we assume the occurrence of a gastrocolic reflex in suncus, similar to that observed in humans and dogs. We also examined the factors that regulate suncus GMCs. Intravenous administration of 5-HT (100 µg/kg), substance P (10 and 100 µg/kg), calcitonin gene-related peptide (10 µg/kg), and α2 adrenergic receptor antagonist yohimbine (0.5, 1, and 3 mg/kg) induced GMC-like contractions, as did intragastric and intracolonic administration of the transient receptor potential vanilloid 1 agonist, capsaicin (1 mg/kg). CONCLUSIONS & INFERENCES These results indicate that the fundamental mechanisms of colonic motility in suncus are similar to those in humans and dogs, and we thus propose that suncus could serve as a novel small animal model for studying colonic motility.
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Affiliation(s)
- Yuki Kobayashi
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Shota Takemi
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Takafumi Sakai
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Chikashi Shibata
- Division of Faculty of Medicine, Department of Gastroenterologic Surgery, Tohoku Medical and Pharmacological University, Sendai, Japan
| | - Ichiro Sakata
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan.,Division of Strategy Research, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
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6
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Zhang S, Kaiya H, Teraoka H, Kitazawa T. Pheasant motilin, its distribution and gastrointestinal contractility-stimulating action in the pheasant. Gen Comp Endocrinol 2021; 314:113897. [PMID: 34506789 DOI: 10.1016/j.ygcen.2021.113897] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 08/17/2021] [Accepted: 09/01/2021] [Indexed: 11/16/2022]
Abstract
Previously, pheasant motilin was identified as a 22-amino acid peptide with a sequence of FVPFFTQSDI QKMQEKERIK GQ. In the present study, the distribution of pheasant motilin mRNA was determined and compared with that of ghrelin, a motilin-related peptide. The effects of pheasant motilin on the cognate gastrointestinal (GI) muscle strips were also examined in an in vitro contraction study. The expression of pheasant motilin mRNA was highest in the small intestine (duodenum, jejunum and ileum), moderate in the colon and very low in the brain, lung, heart, pancreas, esophagus, proventriculus, gizzard and caecum, and this distribution was in contrast with that of ghrelin mRNA. Pheasant motilin caused contraction of the cognate GI tract in a region-dependent manner, similar to chicken motilin. The contraction in the small intestine was large and was not affected by atropine. In contrast, contraction in the proventriculus was small and was decreased by atropine. The crop and colon were insensitive to pheasant motilin. Neither GM109 nor MA2029, mammalian motilin receptor antagonists inhibited the contractions of pheasant motilin. Erythromycin was ineffective in the pheasant ileum, although it caused contraction of the rabbit duodenum. These results indicate that pheasant motilin caused contraction through an action on smooth muscles in the small intestine and an action on enteric cholinergic nerves in the proventriculus. This high responsiveness of the small intestine suggests that motilin is a regulator of small intestinal motility in avians, and the characteristic of the motilin receptor in the pheasant might be different from that in mammals, as is that in chickens.
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Affiliation(s)
- Shuangyi Zhang
- School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan
| | - Hiroyuki Kaiya
- Department of Biochemistry, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka 565-8565, Japan
| | - Hiroki Teraoka
- School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan
| | - Takio Kitazawa
- School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan.
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7
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Kitazawa T, Kaiya H. Motilin Comparative Study: Structure, Distribution, Receptors, and Gastrointestinal Motility. Front Endocrinol (Lausanne) 2021; 12:700884. [PMID: 34497583 PMCID: PMC8419268 DOI: 10.3389/fendo.2021.700884] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 07/16/2021] [Indexed: 12/26/2022] Open
Abstract
Motilin, produced in endocrine cells in the mucosa of the upper intestine, is an important regulator of gastrointestinal (GI) motility and mediates the phase III of interdigestive migrating motor complex (MMC) in the stomach of humans, dogs and house musk shrews through the specific motilin receptor (MLN-R). Motilin-induced MMC contributes to the maintenance of normal GI functions and transmits a hunger signal from the stomach to the brain. Motilin has been identified in various mammals, but the physiological roles of motilin in regulating GI motility in these mammals are well not understood due to inconsistencies between studies conducted on different species using a range of experimental conditions. Motilin orthologs have been identified in non-mammalian vertebrates, and the sequence of avian motilin is relatively close to that of mammals, but reptile, amphibian and fish motilins show distinctive different sequences. The MLN-R has also been identified in mammals and non-mammalian vertebrates, and can be divided into two main groups: mammal/bird/reptile/amphibian clade and fish clade. Almost 50 years have passed since discovery of motilin, here we reviewed the structure, distribution, receptor and the GI motility regulatory function of motilin in vertebrates from fish to mammals.
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Affiliation(s)
- Takio Kitazawa
- Comparative Animal Pharmacology, Department of Veterinary Science, Rakuno Gakuen University, Ebetsu, Japan
| | - Hiroyuki Kaiya
- Department of Biochemistry, National Cerebral and Cardiovascular Center Research Institute, Suita, Japan
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8
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Sekiya H, Yokota N, Takemi S, Nakayama K, Okada H, Sakai T, Sakata I. The inhibitory effect of somatostatin on gastric motility in Suncus murinus. J Smooth Muscle Res 2021; 56:69-81. [PMID: 33473062 PMCID: PMC7817339 DOI: 10.1540/jsmr.56.69] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Gastric contractions show two specific patterns in many species, migrating motor
contractions (MMC) and postprandial contractions (PPCs), that occur in the fasted and fed
states, respectively. In this study, we examined the role of somatostatin (SST) in gastric
motility both in vivo and in vitro using the Asian house
shrew (Suncus murinus). We performed in vivo recordings
of gastric motility and in vitro organ bath experiments using S.
murinus, which was recently established as a small laboratory animal for use in
tests of gastrointestinal motility. SST (1.65 µg kg−1 min−1) was
intravenously administered during phase II of MMC and PPCs. Next, the effect of SST on
motilin-induced gastric contractions at phase I of MMC was measured. Cyclosomatostatin
(CSST), an SST receptor antagonist, was administered at the peak of phase III of MMC. In
addition, the effect of SST (10−11–10−9 M) on motilin-induced
gastric contractions was evaluated using an organ bath experiment in
vitro. In conscious, free-moving S. murinus, the
administration of SST decreased the occurrence of the spontaneous phase II of MMC and
PPCs. Pretreatment with SST and octreotide suppressed the induction of motilin-induced
gastric contractions both in vivo and in vitro.
Administration of CSST before the peak of spontaneous phase III contractions had no effect
on gastric contractions. Endogenous SST is not involved in the regulation of gastric MMC
and PPCs, but exogenous SST suppresses spontaneous gastric contractions. Thus, SST would
be good for treating abnormal gastrointestinal motility disorders.
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Affiliation(s)
- Haruka Sekiya
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan
| | - Naho Yokota
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan
| | - Shota Takemi
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan
| | - Keiji Nakayama
- Research Center of Neurology, Discovery and Research, Ono Pharmaceutical Co., Ltd., 3-1-1 Sakurai, Shimamoto-cho, Mishima-gun, Osaka 618-8585, Japan
| | - Hiroki Okada
- Discovery Technology Research Laboratories, Discovery and Research, Ono Pharmaceutical Co., Ltd., 3-1-1 Sakurai, Shimamoto-cho, Mishima-gun, Osaka 618-8585, Japan
| | - Takafumi Sakai
- Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama 338-8570, Japan
| | - Ichiro Sakata
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan.,Area of Life-NanoBio, Division of Strategy Research, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama 338-8570, Japan
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9
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Zhang S, Teraoka H, Kaiya H, Kitazawa T. Motilin- and ghrelin-induced contractions in isolated gastrointestinal strips from three species of frogs. Gen Comp Endocrinol 2021; 300:113649. [PMID: 33153968 DOI: 10.1016/j.ygcen.2020.113649] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 10/07/2020] [Accepted: 10/17/2020] [Indexed: 12/26/2022]
Abstract
Ghrelin (GHRL) and motilin (MLN), gut peptides isolated from the mucosa of the stomach and duodenum, respectively, stimulate gastrointestinal (GI) motility in mammals and birds. However, the functions of MLN and GHRL in amphibian GI tracts have not been examined in detail. To clarify the regulation of GI motility by the two peptides, the effects of human MLN and rat GHRL on contractility of isolated GI strips from three species of frogs, the black-spotted pond frog (pond frog; Pelophylax nigromaculata), bullfrog (Lithobates catesbeiana) and Western clawed frog (Xenopus; Xenopus tropicalis), were examined in in vitro experiments. The GI tract of each frog was divided into the stomach, upper intestine, middle intestine and lower intestine. Human MLN caused contractions of the stomach in the pond frog and upper intestine in the bullfrog and Xenopus, but other GI regions were insensitive to human MLN. Erythromycin did not cause contraction of the upper intestine of the bullfrog and Xenopus. Rat GHRL did not cause contraction of the stomach and small intestines in the pond frog and bullfrog, but it caused a concentration-dependent contraction in the stomach and upper intestine of Xenopus, while des-acyl rat GHRL did not cause any contraction of them. In conclusion, human MLN caused the contraction of the stomach or upper intestine in the three species of frogs, but GHRL was effective only in the stomach and upper intestine of Xenopus. On the basis of these data, MLN but not GHRL causes the GI region-dependent contractions in the frogs.
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Affiliation(s)
- Shuangyi Zhang
- School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan
| | - Hiroki Teraoka
- School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan
| | - Hiroyuki Kaiya
- Department of Biochemistry, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka 564-8565, Japan
| | - Takio Kitazawa
- School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan.
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10
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Takakura N, Takemi S, Kumaki S, Matsumoto M, Sakai T, Iwatsuki K, Sakata I. Generation and characterization of Suncus murinus intestinal organoid: a useful tool for studying motilin secretion. Cell Biol Int 2020; 44:62-69. [PMID: 31293061 DOI: 10.1002/cbin.11201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 07/08/2019] [Indexed: 01/24/2023]
Abstract
Motilin, a 22-amino-acid peptide produced in the upper small intestine, induces strong gastric contraction in fasted state. In many rodents, motilin and its cognate receptors exist as pseudogenes, which has delayed motilin research in the past decades. Recently, the house musk shrew (Suncus murinus) was developed as a useful model for studying motilin and gastrointestinal motility. However, due to a lack of motilin-producing cell lines and difficulties in culturing small intestinal cells, the regulatory mechanisms of motilin secretion and its messenger RNA (mRNA) transcription have remained largely unclear. In this study, we generated small intestinal organoids from S. murinus for the first time. Using methods similar to mouse organoid generation, we found crypt-like budding structures 3 days after isolating intestinal tissues. The organoids grew gradually with time. In addition, the generated organoids were able to be passaged and maintained for 6 months or longer. Motilin messenger RNA (mRNA) and immunopositive cells were observed in both S. murinus intestinal organoids and primary tissues. This is the first report of intestinal organoids in S. murinus, and our results suggest that S. murinus intestinal organoids could be useful for analyzing motilin secretion and transcription.
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Affiliation(s)
- Natsumi Takakura
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama, 338-8570, Japan
| | - Shota Takemi
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama, 338-8570, Japan
| | - Shunsuke Kumaki
- Department of Nutritional Science and Food Safety, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, 156-8502, Japan
| | - Mio Matsumoto
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama, 338-8570, Japan
| | - Takafumi Sakai
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama, 338-8570, Japan.,Area of Life-NanoBio, Division of Strategy, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama, 338-8570, Japan
| | - Ken Iwatsuki
- Department of Nutritional Science and Food Safety, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, 156-8502, Japan
| | - Ichiro Sakata
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama, 338-8570, Japan
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11
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Zhang S, Okuhara Y, Iijima M, Takemi S, Sakata I, Kaiya H, Teraoka H, Kitazawa T. Identification of pheasant ghrelin and motilin and their actions on contractility of the isolated gastrointestinal tract. Gen Comp Endocrinol 2020; 285:113294. [PMID: 31585115 DOI: 10.1016/j.ygcen.2019.113294] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 09/02/2019] [Accepted: 09/29/2019] [Indexed: 12/11/2022]
Abstract
Motilin and ghrelin were identified in the pheasant by molecular cloning, and the actions of both peptides on the contractility of gastrointestinal (GI) strips were examined in vitro. Molecular cloning indicated that the deduced amino acid sequences of the pheasant motilin and ghrelin were a 22-amino acid peptide, FVPFFTQSDIQKMQEKERIKGQ, and a 26-amino acid peptide, GSSFLSPAYKNIQQQKDTRKPTGRLH, respectively. In in vitro studies using pheasant GI strips, chicken motilin caused contraction of the proventriculus and small intestine, whereas the crop and colon were insensitive. Human motilin, but not erythromycin, caused contraction of small intestine. Chicken motilin-induced contractions in the proventriculus and ileum were not inhibited by a mammalian motilin receptor antagonist, GM109. Neither atropine (a cholinergic receptor antagonist) nor tetrodotoxin (a neuron blocker) inhibited the responses of chicken motilin in the ileum but both drugs decreased the responses to motilin in the proventriculus, suggesting that the contractile mechanisms of motilin in the proventriculus was neurogenic, different from that of the small intestine (myogenic). On the other hand, chicken and quail ghrelin did not cause contraction in any regions of pheasant GI tract. Since interaction of ghrelin and motilin has been reported in the house musk shrew, interaction of two peptides was examined. The chicken motilin-induced contractions were not modified by ghrelin, and ghrelin also did not cause any contraction under the presence of motilin, suggesting the absence of interaction in both peptides. In conclusion, both the motilin system and ghrelin system are present in the pheasant. Regulation of GI motility by motilin might be common in avian species. However, absence of ghrelin actions in any GI regions suggests the avian species-related difference in regulation of GI contractility by ghrelin.
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Affiliation(s)
- Shuangyi Zhang
- Department of Veterinary Science, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan; School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan
| | - Yuji Okuhara
- School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan
| | - Mio Iijima
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama 338-8570, Japan
| | - Shota Takemi
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama 338-8570, Japan
| | - Ichiro Sakata
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama 338-8570, Japan
| | - Hiroyuki Kaiya
- Department of Biochemistry, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka 565-8565, Japan
| | - Hiroki Teraoka
- School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan
| | - Takio Kitazawa
- Department of Veterinary Science, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan.
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12
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Shinohara A, Nohara M, Kondo Y, Jogahara T, Nagura-Kato GA, Izawa M, Koshimoto C. Comparison of the gut microbiotas of laboratory and wild Asian house shrews (Suncus murinus) based on cloned 16S rRNA sequences. Exp Anim 2019; 68:531-539. [PMID: 31217361 PMCID: PMC6842809 DOI: 10.1538/expanim.19-0021] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The Asian house shrew, Suncus murinus, is an insectivore (Eulipotyphla,
Mammalia) and an important laboratory animal for life-science studies. The
gastrointestinal tract of Suncus is simple: the length of the entire
intestine is very short relative to body size, the large intestine is quite short, and
there are no fermentative chambers such as the forestomach or cecum. These features imply
that Suncus has a different nutritional physiology from those of humans
and mice, but little is known about whether Suncus utilizes microbial
fermentation in the large (LI) or small (SI) intestine. In addition, domestication may
affect the gastrointestinal microbial diversity of Suncus. Therefore, we
compared the gastrointestinal microbial diversity of Suncus between
laboratory and wild Suncus and between the SI and LI
(i.e., four groups: Lab-LI, Lab-SI, Wild-LI, and Wild-SI) using
bacterial 16S rRNA gene library sequencing analyses with a sub-cloning method. We obtained
759 cloned sequences (176, 174, 195, and 214 from the Lab-LI, Lab-SI, Wild-LI, and Wild-SI
samples, respectively), which revealed that the gastrointestinal microbiota of
Suncus is rich in Firmicutes (mostly lactic acid bacteria), with few
Bacteroidetes. We observed different bacterial communities according to intestinal region
in laboratory Suncus, but not in wild Suncus.
Furthermore, the gastrointestinal microbial diversity estimates were lower in laboratory
Suncus than in wild Suncus. These results imply that
Suncus uses lactic acid fermentation in the gut, and that the
domestication process altered the gastrointestinal bacterial diversity.
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Affiliation(s)
- Akio Shinohara
- Division of Bio-resources, Department of Biotechnology, Frontier Science Research Center, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan
| | - Makoto Nohara
- Division of Bio-resources, Department of Biotechnology, Frontier Science Research Center, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan.,Present Address: WDB EUREKA Co., Ltd., 2-3-2 Marunouchi, Chiyoda-ku, Tokyo, Japan
| | - Yuta Kondo
- Division of Bio-resources, Department of Biotechnology, Frontier Science Research Center, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan
| | - Takamichi Jogahara
- Division of Bio-resources, Department of Biotechnology, Frontier Science Research Center, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan.,Present Address: Faculty of Law and Economics, Okinawa University, 555 Kokuba, Naha, Okinawa 902-8521, Japan
| | - Goro A Nagura-Kato
- Division of Bio-resources, Department of Biotechnology, Frontier Science Research Center, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan
| | - Masako Izawa
- Faculty of Science, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213, Japan
| | - Chihiro Koshimoto
- Division of Bio-resources, Department of Biotechnology, Frontier Science Research Center, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan
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13
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Horita T, Koyama K, Takemi S, Tanaka T, Sakai T, Sakata I. GABAergic and glutamatergic neurons in the brain regulate phase II of migrating motor contractions in the Suncus murinus. J Smooth Muscle Res 2019; 54:91-99. [PMID: 30787212 PMCID: PMC6380905 DOI: 10.1540/jsmr.54.91] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Gastric contractions exhibit characteristic motor patterns in the fasted state, known as
migrating motor contractions (MMC). MMC consist of three periodically repeated phases
(phase I, II and III) and are known to be regulated by hormones and the autonomic and
enteric nervous systems. However, the central regulation of gastric contractions in the
fasted state is not completely understood. Here, we have examined the central effects of
motilin, ghrelin, γ-aminobutyric acid (GABA) and L-glutamate signaling on gastric MMC by
using suncus (Suncus murinus) as an animal model, because of their
similar gastric motor patterns to those observed in humans and dogs.
Intracerebroventricular (i.c.v.) administration of motilin and ghrelin had no effect on
phase I and II contractions, respectively. Conversely, i.c.v. administration of
GABAA receptor antagonist, during phase I of the MMC, evoked phase II-like
contractions and significantly increased the motility index (MI). This was compared with
the i.c.v. administration of GABA which inhibited spontaneous phase II contractions with a
significantly decreased MI. In addition, i.c.v. administration of L-glutamate during phase
I also induced phase II-like irregular contractions with a significant increase in the MI.
Taken together with previous findings, these results suggest that central GABAergic and
glutamatergic signaling, with the coordination of both peripheral motilin and ghrelin,
regulate phase II contractions of MMC in the fasted state.
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Affiliation(s)
- Taichi Horita
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan
| | - Kouhei Koyama
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan
| | - Shota Takemi
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan
| | - Toru Tanaka
- Faculty of Pharmaceutical Sciences, Department of Pharmaceutical and Health Sciences, Josai University, 1-1 Keiyaki dai, Sakado, Saitama 350-0295, Japan
| | - Takafumi Sakai
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan.,Area of Life-NanoBio, Division of Strategy Research, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama 338-8570, Japan
| | - Ichiro Sakata
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama 338-8570, Japan
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14
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Utility of animal gastrointestinal motility and transit models in functional gastrointestinal disorders. Best Pract Res Clin Gastroenterol 2019; 40-41:101633. [PMID: 31594654 DOI: 10.1016/j.bpg.2019.101633] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 07/17/2019] [Indexed: 01/31/2023]
Abstract
Alteration in the gastrointestinal (GI) motility and transit comprises an important component of the functional gastrointestinal disorders (FGID). Available animal GI motility and transit models are to study symptoms (delayed gastric emptying, constipation, diarrhea) rather than biological markers to develop an effective treatment that targets the underlying mechanism of altered GI motility in patients. Animal data generated from commonly used methods in human like scintigraphy, breath test and wireless motility capsule may directly translate to the clinic. However, species differences in the control mechanism or pharmacological responses of GI motility may compromise the predictive and translational value of the preclinical data to human. In this review we aim to provide a summary on animal models used to mimic GI motility alteration in FGID, and the impact of the species differences in the physiological and pharmacological responses on the translation of animal GI motility and transit data to human.
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15
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Kitazawa T, Harada R, Sakata I, Sakai T, Kaiya H. A verification study of gastrointestinal motility-stimulating action of guinea-pig motilin using isolated gastrointestinal strips from rabbits and guinea-pigs. Gen Comp Endocrinol 2019; 274:106-112. [PMID: 30677392 DOI: 10.1016/j.ygcen.2019.01.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Revised: 01/07/2019] [Accepted: 01/17/2019] [Indexed: 12/13/2022]
Abstract
Motilin (MLN), a 22-amino-acid peptide hormone, is generally present in the mucosa of the upper gastrointestinal (GI) tract, mainly the duodenum of mammals, and it regulates GI motility, especially that related to interdigestive migrating contraction. However, MLN and its receptor are absent in mice and rats, and MLN does not cause any mechanical responses in the rat and mouse GI tracts. The guinea-pig is also a rodent, but expression of the MLN gene in the guinea-pig has been reported. In the present study, two guinea-pig MLNs, FIPIFTYSELRRTQEREQNKGL found in the Ensemble Genome Database (gpMLN-1) and FVPIFTYSELRRTQEREQNKRL reported by Xu et al. (2001) (gpMLN-2), were synthesized, and their biological activities were evaluated in the rabbit duodenum and guinea-pig GI tract in vitro. Both gpMLNs showed contractile activity in longitudinal muscle strips of the rabbit duodenum. The EC50 values of gpMLN-1 and gpMLN-2 were slightly higher than that of human MLN (hMLN), but the maximum contractions were as same as that of hMLN. Treatment with GM109 and hMLN-induced receptor desensitization decreased the contractile activity of both gpMLNs, indicating that the two gpMLN candidates are able to activate the MLN receptor (MLN-R) of the rabbit duodenum. In guinea-pig GI preparations, hMLN and gpMLNs did not show any mechanical responses in circular muscle strips from the gastric antrum or in longitudinal strips of the duodenum, ileum and colon although acetylcholine and 1,1-dimethyl-4-phenylpiperazinium (DMPP) caused definite mechanical responses. The DMPP-induced neural responses in the gastric circular muscle and ileal longitudinal muscles were not modified by gpMLN-1. Even in the gastric and ileal strips with intact mucosa, no mechanical responses were seen with either of the gpMLNs. Furthermore, RT-PCR using various primer sets failed to amplify the gpMLN-2 mRNA. In conclusion, gpMLNs including one that was already reported and the other that was newly found in a database were effective to the rabbit MLN-R, whereas they did not cause any contractions or modification of neural responses in the guinea-pig GI tract, indicating that the MLN system is vestigial and not functional in regulation of GI motility in the guinea-pig as well as in other rodents such as rats and mice.
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Affiliation(s)
- Takio Kitazawa
- Department of Veterinary Science, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan.
| | - Rio Harada
- Department of Veterinary Science, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan
| | - Ichiro Sakata
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama 338-8570, Japan
| | - Takafumi Sakai
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama 338-8570, Japan
| | - Hiroyuki Kaiya
- Department of Biochemistry, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka 565-8565, Japan
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16
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Kitazawa T, Kaiya H. Regulation of Gastrointestinal Motility by Motilin and Ghrelin in Vertebrates. Front Endocrinol (Lausanne) 2019; 10:278. [PMID: 31156548 PMCID: PMC6533539 DOI: 10.3389/fendo.2019.00278] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 04/16/2019] [Indexed: 12/14/2022] Open
Abstract
The energy balance of vertebrates is regulated by the difference in energy input and energy expenditure. Generally, most vertebrates obtain their energy from nutrients of foods through the gastrointestinal (GI) tract. Therefore, food intake and following food digestion, including motility of the GI tract, secretion and absorption, are crucial physiological events for energy homeostasis. GI motility changes depending on feeding, and GI motility is divided into fasting (interdigestive) and postprandial (digestive) contraction patterns. GI motility is controlled by contractility of smooth muscles of the GI tract, extrinsic and intrinsic neurons (motor and sensory) and some hormones. In mammals, ghrelin (GHRL) and motilin (MLN) stimulate appetite and GI motility and contribute to the regulation of energy homeostasis. GHRL and MLN are produced in the mucosal layer of the stomach and upper small intestine, respectively. GHRL is a multifunctional peptide and is involved in glucose metabolism, endocrine/exocrine functions and cardiovascular and reproductive functions, in addition to feeding and GI motility in mammals. On the other hand, the action of MLN is restricted and species such as rodentia, including mice and rats, lack MLN peptide and its receptor. From a phylogenetic point of view, GHRL and its receptor GHS-R1a have been identified in various vertebrates, and their structural features and various physiological functions have been revealed. On the other hand, MLN or MLN-like peptide (MLN-LP) and its receptors have been found only in some fish, birds and mammals. Here, we review the actions of GHRL and MLN with a focus on contractility of the GI tract of species from fish to mammals.
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Affiliation(s)
- Takio Kitazawa
- Comparative Animal Pharmacology, Department of Veterinary Science, Rakuno Gakuen University, Ebetsu, Japan
- *Correspondence: Takio Kitazawa
| | - Hiroyuki Kaiya
- Department of Biochemistry, National Cerebral and Cardiovascular Center Research Institute, Suita, Japan
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17
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Ikenoya C, Takemi S, Kaminoda A, Aizawa S, Ojima S, Gong Z, Chacrabati R, Kondo D, Wada R, Tanaka T, Tsuda S, Sakai T, Sakata I. β-Oxidation in ghrelin-producing cells is important for ghrelin acyl-modification. Sci Rep 2018; 8:9176. [PMID: 29907775 PMCID: PMC6003948 DOI: 10.1038/s41598-018-27458-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 06/01/2018] [Indexed: 12/30/2022] Open
Abstract
Ghrelin is a unique fatty acid-modified peptide hormone produced in the stomach and has important roles in energy homeostasis and gastrointestinal motility. However, the medium-chain fatty acid source for ghrelin acyl-modification is not known. We found that a fat-free diet and the removal of intestinal microbiota did not decrease acyl-ghrelin production in the stomach or plasma acyl-ghrelin levels in mice. RT-PCR analysis showed that genes involving fatty acid synthesis, metabolism, and transport were expressed in pancreas-derived ghrelinoma (PG-1) cells. Treatment with an irreversible inhibitor of carnitine palmitoyltransferase-1 (CPT-1) strongly decreased acylated ghrelin levels but did not affect ghrelin or ghrelin o-acyl transferase (GOAT) mRNA levels in PG-1 cells. Our results suggest that the medium-chain fatty acid used for the acyl-modification of ghrelin is produced in ghrelin-producing cells themselves by β-oxidation of long-chain fatty acids provided from the circulation.
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Affiliation(s)
- Chika Ikenoya
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama, 338-8570, Japan
| | - Shota Takemi
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama, 338-8570, Japan
| | - Arisa Kaminoda
- Department of Biology, Graduate School of Natural Science and Technology, Okayama University, 3-1-1, Tsushimanaka, Kita-ku, Okayama, 700-8530, Japan
| | - Sayaka Aizawa
- Department of Biology, Graduate School of Natural Science and Technology, Okayama University, 3-1-1, Tsushimanaka, Kita-ku, Okayama, 700-8530, Japan
| | - Shiomi Ojima
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama, 338-8570, Japan
| | - Zhi Gong
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama, 338-8570, Japan
| | - Rakhi Chacrabati
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama, 338-8570, Japan
| | - Daisuke Kondo
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama, 338-8570, Japan
| | - Reiko Wada
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama, 338-8570, Japan
| | - Toru Tanaka
- Faculty of Pharmaceutical Sciences, Department of Pharmaceutical and Health Sciences, Josai University, 1-1 Keiyaki dai, Sakado, Saitama, 350-0295, Japan
| | - Sachiko Tsuda
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama, 338-8570, Japan.,Research and Development Bureau, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama, 338-8570, Japan
| | - Takafumi Sakai
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama, 338-8570, Japan.,Area of Life-NanoBio, Division of Strategy Research, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Ichiro Sakata
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakuraku, Saitama, 338-8570, Japan.
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18
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Mikami T, Ito K, Diaz-Tartera HO, Hellström PM, Mochiki E, Takemi S, Tanaka T, Tsuda S, Jogahara T, Sakata I, Sakai T. Study of termination of postprandial gastric contractions in humans, dogs and Suncus murinus: role of motilin- and ghrelin-induced strong contraction. Acta Physiol (Oxf) 2018; 222. [PMID: 28786555 DOI: 10.1111/apha.12933] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 06/07/2017] [Accepted: 08/01/2017] [Indexed: 12/16/2022]
Abstract
AIM Stomach contractions show two types of specific patterns in many species, that is migrating motor contraction (MMC) and postprandial contractions (PPCs), in the fasting and fed states respectively. We found gastric PPCs terminated with migrating strong contractions in humans, dogs and suncus. In this study, we reveal the detailed characteristics and physiological implications of these strong contractions of PPC. METHODS Human, suncus and canine gastric contractions were recorded with a motility-monitoring ingestible capsule and a strain-gauge force transducer. The response of motilin and ghrelin and its receptor antagonist on the contractions were studied by using free-moving suncus. RESULTS Strong gastric contractions were observed at the end of a PPC in human, dog and suncus models, and we tentatively designated this contraction to be a postprandial giant contraction (PPGC). In the suncus, the PPGC showed the same property as those of a phase III contraction of MMC (PIII-MMC) in the duration, motility index and response to motilin or ghrelin antagonist administration. Ghrelin antagonist administration in the latter half of the PPC (LH-PPC) attenuated gastric contraction prolonged the duration of occurrence of PPGC, as found in PII-MMC. CONCLUSION It is thought that the first half of the PPC changed to PII-MMC and then terminated with PIII-MMC, suggesting that PPC consists of a digestive phase (the first half of the PPC) and a discharge phase (LH-PPC) and that LH-PPC is coincident with MMC. In this study, we propose a new approach for the understanding of postprandial contractions.
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Affiliation(s)
- T. Mikami
- Area of Regulatory Biology; Division of Life Science; Graduate School of Science and Engineering; Saitama University; Saitama Japan
| | - K. Ito
- Area of Regulatory Biology; Division of Life Science; Graduate School of Science and Engineering; Saitama University; Saitama Japan
| | | | - P. M. Hellström
- Department of Medical Sciences; Uppsala University; Uppsala Sweden
| | - E. Mochiki
- Department of Digestive Tract and General Surgery; Saitama Medical Center; Saitama Medical University; Kawagoe Japan
| | - S. Takemi
- Area of Regulatory Biology; Division of Life Science; Graduate School of Science and Engineering; Saitama University; Saitama Japan
| | - T. Tanaka
- Department of Pharmaceutical and Health Sciences; Faculty of Pharmaceutical Sciences; Josai University; Saitama Japan
| | - S. Tsuda
- Area of Regulatory Biology; Division of Life Science; Graduate School of Science and Engineering; Saitama University; Saitama Japan
| | - T. Jogahara
- Laboratory of Animal Management and Resources; Department of Zoology; Faculty of Science; Okayama University of Science; Okayama Japan
| | - I. Sakata
- Area of Regulatory Biology; Division of Life Science; Graduate School of Science and Engineering; Saitama University; Saitama Japan
| | - T. Sakai
- Area of Life-NanoBio; Division of Strategy Research, Graduate School of Science and Engineering; Saitama University; Saitama Japan
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19
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Mondal A, Koyama K, Mikami T, Horita T, Takemi S, Tsuda S, Sakata I, Sakai T. Underlying mechanism of the cyclic migrating motor complex in Suncus murinus: a change in gastrointestinal pH is the key regulator. Physiol Rep 2017; 5:5/1/e13105. [PMID: 28082431 PMCID: PMC5256163 DOI: 10.14814/phy2.13105] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 12/04/2016] [Accepted: 12/08/2016] [Indexed: 02/07/2023] Open
Abstract
In the fasted gastrointestinal (GI) tract, a characteristic cyclical rhythmic migrating motor complex (MMC) occurs in an ultradian rhythm, at 90–120 min time intervals, in many species. However, the underlying mechanism directing this ultradian rhythmic MMC pattern is yet to be completely elucidated. Therefore, this study aimed to identify the possible causes or factors that involve in the occurrence of the fasting gastric contractions by using Suncus murinus a small model animal featuring almost the same rhythmic MMC as that found in humans and dogs. We observed that either intraduodenal infusion of saline at pH 8 evoked the strong gastric contraction or continuously lowering duodenal pH to 3‐evoked gastric phase II‐like and phase III‐like contractions, and both strong contractions were essentially abolished by the intravenous administration of MA 2029 (motilin receptor antagonist) and D‐Lys3‐GHRP6 (ghrelin receptor antagonist) in a vagus‐independent manner. Moreover, we observed that the prostaglandin E2‐alpha (PGE2‐α) and serotonin type 4 (5HT4) receptors play important roles as intermediate molecules in changes in GI pH and motilin release. These results suggest a clear insight mechanism that change in the duodenal pH to alkaline condition is an essential factor for stimulating the endogenous release of motilin and governs the fasting MMC in a vagus‐independent manner. Finally, we believe that the changes in duodenal pH triggered by flowing gastric acid and the release of duodenal bicarbonate through the involvement of PGE2‐α and 5HT4 receptor are the key events in the occurrence of the MMC.
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Affiliation(s)
- Anupom Mondal
- Department of Life Nano-Bio, Strategic Research Division, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Kouhei Koyama
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Takashi Mikami
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Taichi Horita
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Shota Takemi
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Sachiko Tsuda
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Ichiro Sakata
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Takafumi Sakai
- Department of Life Nano-Bio, Strategic Research Division, Graduate School of Science and Engineering, Saitama University, Saitama, Japan .,Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
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Takemi S, Sakata I, Kuroda K, Miyano Y, Mondal A, Sakai T. The important role of ghrelin on gastric contraction in Suncus murinus. Endocr J 2017; 64:S11-S14. [PMID: 28652536 DOI: 10.1507/endocrj.64.s11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Ghrelin, a peptide hormone produced in the stomach, has been known to be involved in the regulation of gastric contraction in humans and rodents. To elucidate the detailed mechanisms of ghrelin on gastric contractions, we used Suncus murinus, a recently established small animal model for gastrointestinal motility. S. murinus produces motilin, a family peptide of ghrelin, and its stomach anatomy and physiological patterns of gastric contractions, in fed and fasted states, are closely similar to humans. Ghrelin administration in phase II, and latter half of phase I, of the migrating motor contractions (MMC) enhanced gastric motility in S. murinus. In addition, we showed that ghrelin and motilin coordinately stimulated strong gastric contractions in vitro and in vivo. We also demonstrated that a pretreatment with a ghrelin antagonist, D-Lys3-GHRP6, inhibited the effects of motilin-induced gastric contractions, and a γ-aminobutyric acid (GABA) antagonist reversed this inhibition. Our results suggest that ghrelin is essential for motilin-induced gastric contractions and that ghrelin-mediated GABAergic neurons are involved in this neural pathway.
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Affiliation(s)
- Shota Takemi
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan
| | - Ichiro Sakata
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan
| | - Kayuri Kuroda
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan
| | - Yuki Miyano
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan
| | - Anupon Mondal
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan
| | - Takafumi Sakai
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan
- Area of Life-Nanobio, Division of Strategy Research, Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan
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Apu AS, Mondal A, Kitazawa T, Takemi S, Sakai T, Sakata I. Molecular cloning of motilin and mechanism of motilin-induced gastrointestinal motility in Japanese quail. Gen Comp Endocrinol 2016; 233:53-62. [PMID: 27179882 DOI: 10.1016/j.ygcen.2016.05.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 05/10/2016] [Accepted: 05/11/2016] [Indexed: 12/16/2022]
Abstract
Motilin, a peptide hormone produced in the upper intestinal mucosa, plays an important role in the regulation of gastrointestinal (GI) motility. In the present study, we first determined the cDNA and amino acid sequences of motilin in the Japanese quail and studied the distribution of motilin-producing cells in the gastrointestinal tract. We also examined the motilin-induced contractile properties of quail GI tracts using an in vitro organ bath, and then elucidated the mechanisms of motilin-induced contraction in the proventriculus and duodenum of the quail. Mature quail motilin was composed of 22 amino acid residues, which showed high homology with chicken (95.4%), human (72.7%), and dog (72.7%) motilin. Immunohistochemical analysis showed that motilin-immunopositive cells were present in the mucosal layer of the duodenum (23.4±4.6cells/mm(2)), jejunum (15.2±0.8cells/mm(2)), and ileum (2.5±0.7cells/mm(2)), but were not observed in the crop, proventriculus, and colon. In the organ bath study, chicken motilin induced dose-dependent contraction in the proventriculus and small intestine. On the other hand, chicken ghrelin had no effect on contraction in the GI tract. Motilin-induced contraction in the duodenum was not inhibited by atropine, hexamethonium, ritanserin, ondansetron, or tetrodotoxin. However, motilin-induced contractions in the proventriculus were significantly inhibited by atropine and tetrodotoxin. These results suggest that motilin is the major stimulant of GI contraction in quail, as it is in mammals and the site of action of motilin is different between small intestine and proventriculus.
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Affiliation(s)
- Auvijit Saha Apu
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama 338-8570, Japan
| | - Anupom Mondal
- Area of Life-NanoBio, Division of Strategy Research, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama 338-8570, Japan
| | - Takio Kitazawa
- Comparative Animal Pharmacology Department of Veterinary Science, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan
| | - Shota Takemi
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama 338-8570, Japan
| | - Takafumi Sakai
- Area of Life-NanoBio, Division of Strategy Research, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama 338-8570, Japan
| | - Ichiro Sakata
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama 338-8570, Japan.
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Yoshimura M, Mikami T, Kuroda K, Nishida M, Ito K, Mondal A, Koyama K, Jogahara T, Sakata I, Sakai T. Involvement of Transient Receptor Potential Vanilloid Receptor 1, (TRPV1)-Expressing Vagal Nerve in the Inhibitory Effect of Gastric Acidification on Exogenous Motilin-Induced Gastric Phase III Contractions in Suncus murinus. Dig Dis Sci 2016; 61:1501-11. [PMID: 26860510 DOI: 10.1007/s10620-015-4023-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 12/20/2015] [Indexed: 12/18/2022]
Abstract
BACKGROUND Gastric acidification inhibits motilin-induced gastric phase III contractions. However, the underlying mechanism has not been thoroughly investigated. Here, we studied the inhibitory mechanism by gastric acidification on motilin-induced contraction in Suncus murinus (S. murinus). METHODS We measured interdigestive gastric phase III contractions in conscious, freely moving S. murinus, and examined the inhibitory effect of gastric acidification on motilin action and the involvement of the vagus nerve and transient receptor potential vanilloid receptor 1 (TRPV1) in the inhibitory mechanism. RESULTS A bolus injection of motilin evoked phase III-like contractions during intravenous infusion of saline. Intragastric acidification (pH 1.5-2.5) inhibited motilin-induced phase III contractions in a pH-dependent manner and significantly decreased the motility index at a pH below 2.0. In contrast, intraduodenal acidification (pH 2.0) failed to inhibit motilin-induced contractions. Vagotomy significantly alleviated the suppression of motilin-induced gastric contractions under acidic conditions (pH 2.0), suggesting vagus nerve involvement. Moreover, intragastric acidification (pH 2.0) significantly increased the number of c-Fos-positive cells in the nucleus tractus solitarii. In vagotomized S. murinus, the number of c-Fos-positive cells did not change, even under gastric acidification conditions. TRPV1 mRNA was highly expressed in the muscle and mucosal regions of the antrum and the nodose ganglion, whereas was not detected in the upper small intestine. Capsazepin, a TRPV1 antagonist, completely rescued the inhibitory effect of gastric acidification. CONCLUSIONS Gastric acidification in S. murinus inhibits motilin-induced contractions, a finding similar to results observed in humans, while TRPV1-expressing vagus nerves play a role in the inhibitory mechanism.
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Affiliation(s)
- Makoto Yoshimura
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Takashi Mikami
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Kayuri Kuroda
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Maki Nishida
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Kazuma Ito
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Anupom Mondal
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Kouhei Koyama
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Takamichi Jogahara
- Laboratory of Animal Management and Resources, Department of Zoology, Faculty of Science, Okayama University of Science, Okayama, 700-8525, Japan
| | - Ichiro Sakata
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Takafumi Sakai
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama, 338-8570, Japan.
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Dudani A, Aizawa S, Zhi G, Tanaka T, Jogahara T, Sakata I, Sakai T. The proximal gastric corpus is the most responsive site of motilin-induced contractions in the stomach of the Asian house shrew. J Comp Physiol B 2016; 186:665-75. [PMID: 27062028 DOI: 10.1007/s00360-016-0985-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 03/24/2016] [Accepted: 03/29/2016] [Indexed: 11/27/2022]
Abstract
The migrating motor complex (MMC) is responsible for emptying the stomach during the interdigestive period, in preparation for the next meal. It is known that gastric phase III of MMC starts from the proximal stomach and propagates the contraction downwards. We hypothesized that a certain region of the stomach must be more responsive to motilin than others, and that motilin-induced strong gastric contractions propagate from that site. Stomachs of the Suncus or Asian house shrew, a small insectivorous mammal, were dissected and the fundus, proximal corpus, distal corpus, and antrum were examined to study the effect of motilin using an organ bath experiment. Motilin-induced contractions differed in different parts of the stomach. Only the proximal corpus induced gastric contraction even at motilin 10(-10) M, and strong contraction was induced by motilin 10(-9) M in all parts of the stomach. The GPR38 mRNA expression was also higher in the proximal corpus than in the other sections, and the lowest expression was observed in the antrum. GPR38 mRNA expression varied with low expression in the mucosal layer and high expression in the muscle layer. Additionally, motilin-induced contractions in each dissected part of the stomach were inhibited by tetrodotoxin and atropine pretreatment. These results suggest that motilin reactivity is not consistent throughout the stomach, and an area of the proximal corpus including the cardia is the most sensitive to motilin.
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Affiliation(s)
- Amrita Dudani
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Sayaka Aizawa
- Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushimanaka, Kita-ku, Okayama, 700-8530, Japan
| | - Gong Zhi
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Toru Tanaka
- Department of Pharmaceutical and Health Sciences, Faculty of Pharmaceutical Sciences, Josai University, 1-1 Keiyaki dai, Sakado, Saitama, 350-0295, Japan
| | - Takamichi Jogahara
- Laboratory of Animal Management and Resources, Department of Zoology, Faculty of Science, Okayama University of Science, 1-1 Ridaicho, Kita-ku, Okayama, 700-0005, Japan
| | - Ichiro Sakata
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Takafumi Sakai
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama, 338-8570, Japan.
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Kuroda K, Hequing H, Mondal A, Yoshimura M, Ito K, Mikami T, Takemi S, Jogahara T, Sakata I, Sakai T. Ghrelin Is an Essential Factor for Motilin-Induced Gastric Contraction in Suncus murinus. Endocrinology 2015; 156:4437-47. [PMID: 26441238 DOI: 10.1210/en.2015-1561] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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.
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Affiliation(s)
- Kayuri Kuroda
- 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
| | - Huang Hequing
- 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
| | - Anupom Mondal
- 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
| | - Makoto Yoshimura
- 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
| | - Kazuma Ito
- 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
| | - Takashi Mikami
- 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
| | - Shota Takemi
- 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
| | - Takamichi Jogahara
- 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
| | - Ichiro Sakata
- 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
| | - Takafumi Sakai
- 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
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Goswami C, Shimada Y, Yoshimura M, Mondal A, Oda SI, Tanaka T, Sakai T, Sakata I. Motilin Stimulates Gastric Acid Secretion in Coordination with Ghrelin in Suncus murinus. PLoS One 2015; 10:e0131554. [PMID: 26115342 PMCID: PMC4482737 DOI: 10.1371/journal.pone.0131554] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 06/03/2015] [Indexed: 12/13/2022] Open
Abstract
Motilin and ghrelin constitute a peptide family, and these hormones are important for the regulation of gastrointestinal motility. In this study, we examined the effect of motilin and ghrelin on gastric acid secretion in anesthetized suncus (house musk shrew, Suncus murinus), a ghrelin- and motilin-producing mammal. We first established a gastric lumen-perfusion system in the suncus and confirmed that intravenous (i.v.) administration of histamine (1 mg/kg body weight) stimulated acid secretion. Motilin (0.1, 1.0, and 10 μg/kg BW) stimulated the acid output in a dose-dependent manner in suncus, whereas ghrelin (0.1, 1.0, and 10 μg/kg BW) alone did not induce acid output. Furthermore, in comparison with the vehicle administration, the co-administration of low-dose (1 μg/kg BW) motilin and ghrelin significantly stimulated gastric acid secretion, whereas either motilin (1 μg/kg BW) or ghrelin (1 μg/kg BW) alone did not significantly induce gastric acid secretion. This indicates an additive role of ghrelin in motilin-induced gastric acid secretion. We then investigated the pathways of motilin/motilin and ghrelin-stimulated acid secretion using receptor antagonists. Treatment with YM 022 (a CCK-B receptor antagonist) and atropine (a muscarinic acetylcholine receptor antagonist) had no effect on motilin or motilin-ghrelin co-administration-induced acid output. In contrast, famotidine (a histamine H2 receptor antagonist) completely inhibited motilin-stimulated acid secretion and co-administration of motilin and ghrelin induced gastric acid output. This is the first report demonstrating that motilin stimulates gastric secretion in mammals. Our results also suggest that motilin and co-administration of motilin and ghrelin stimulate gastric acid secretion via the histamine-mediated pathway in suncus.
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Affiliation(s)
- Chayon Goswami
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Yoshiaki Shimada
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Makoto Yoshimura
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Anupom Mondal
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Sen-ichi Oda
- Laboratory of Animal Management and Resources, Department of Zoology, Okayama University of Science, Okayama, Japan
| | - Toru Tanaka
- Faculty of Pharmaceutical Sciences, Josai University, Saitama, Japan
| | - Takafumi Sakai
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Ichiro Sakata
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
- * E-mail:
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Mondal A, Takehara A, Aizawa S, Tanaka T, Fujitsuka N, Hattori T, Sakai T, Sakata I. Rikkunshito induces gastric relaxation via the β-adrenergic pathway in Suncus murinus. Neurogastroenterol Motil 2015; 27:875-84. [PMID: 25846270 DOI: 10.1111/nmo.12564] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 03/06/2015] [Indexed: 12/30/2022]
Abstract
BACKGROUND Rikkunshito (RKT) is a gastroprotective herbal medicine. In this study, we investigated the role of RKT in the relaxation of the gastric body (fundus and corpus) and antrum. METHODS We used Suncus murinus, a unique small model animal with similar gastrointestinal motility to humans and dogs. RKT was added at 0.1, 1.0, and 5.0 mg/mL to induce relaxation in vitro; the outcome measure was the intensity of relaxation. The number of spontaneous antral contractions in the absence or the presence of RKT was also counted. KEY RESULTS Rikkunshito induced the relaxation of the gastric body and antrum and decreased the number of spontaneous antral contractions in a dose-dependent manner. The responses to RKT (1.0 mg/mL) were not affected by pretreatment with atropine, N-nitro-l-arginine methyl ester, ritanserin, or ondansetron. On the other hand, timolol almost completely reversed the relaxation induced by RKT (1.0 mg/mL) on the gastric body and antrum and the occurrence of the spontaneous antral contractions. Both butoxamine, a β(2) -adrenoreceptor antagonist, and L 748337, a β(3) -adrenoreceptor antagonist, but not CGP 20712, a β(1) -adrenoreceptor antagonist, significantly reversed the RKT-induced (1.0 mg/mL) gastric relaxation. CONCLUSIONS & INFERENCES These results indicate that RKT stimulates and modulates gastric relaxation through β(2) - and β(3) -adrenergic, but not β(1) -adrenergic, pathways in S. murinus.
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Affiliation(s)
- A Mondal
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - A Takehara
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - S Aizawa
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - T Tanaka
- Faculty of Pharmaceutical Sciences, Josai University, Sakado-shi, Saitama, Japan
| | - N Fujitsuka
- Tsumura Research Laboratories, Tsumura & Co., Ibaraki, Japan
| | - T Hattori
- Tsumura Research Laboratories, Tsumura & Co., Ibaraki, Japan
| | - T Sakai
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - I Sakata
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
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Goswami C, Tanaka T, Jogahara T, Sakai T, Sakata I. Motilin stimulates pepsinogen secretion in Suncus murinus. Biochem Biophys Res Commun 2015; 462:263-8. [PMID: 25957475 DOI: 10.1016/j.bbrc.2015.04.129] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 04/26/2015] [Indexed: 12/13/2022]
Abstract
Motilin and ghrelin are gastrointestinal hormones that stimulate the migrating motor complex (MMC) of gastrointestinal motility during the fasting state. In this study, we examined the effect of motilin and ghrelin on pepsinogen secretion in anesthetized suncus (house musk shrew, Suncus murinus), a ghrelin- and motilin-producing mammal. By using a gastric lumen-perfusion system, we found that the intravenous administration of carbachol and motilin stimulated pepsinogen secretion, the latter in a dose-dependent manner, whereas ghrelin had no effect. We then investigated the pathways of motilin-induced pepsinogen secretion using acetylcholine receptor antagonists. Treatment with atropine, a muscarinic acetylcholine receptor antagonist, completely inhibited both carbachol and motilin-induced pepsinogen secretion. Motilin-induced pepsinogen secretion was observed in the vagotomized suncus. This is the first report demonstrating that motilin stimulates pepsinogen secretion, and suggest that this effect occurs through a cholinergic pathway in suncus.
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Affiliation(s)
- Chayon Goswami
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Toru Tanaka
- Faculty of Pharmaceutical Sciences, Department of Pharmaceutical and Health Sciences, Josai University, Saitama, Japan
| | - Takamichi Jogahara
- Laboratory of Animal Management and Resources, Department of Zoology, Faculty of Science, Okayama University of Science, Okayama, Japan
| | - Takafumi Sakai
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Ichiro Sakata
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan.
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Deloose E, Vos R, Corsetti M, Depoortere I, Tack J. Endogenous motilin, but not ghrelin plasma levels fluctuate in accordance with gastric phase III activity of the migrating motor complex in man. Neurogastroenterol Motil 2015; 27:63-71. [PMID: 25393165 DOI: 10.1111/nmo.12470] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 10/12/2014] [Indexed: 12/15/2022]
Abstract
BACKGROUND Fluctuations in motilin plasma levels have been implicated in the control of the migrating motor complex (MMC). A plasma peak of motilin is present before a gastric phase III. Furthermore, not only exogenous administration of motilin but also ghrelin induces a gastric phase III in man. Aim of this study was to investigate the role of endogenous ghrelin in the regulation of the MMC. METHODS Plasma samples for motilin and ghrelin were taken in between two consecutive phases III of either origin measured using high-resolution manometry. KEY RESULTS The duration of 1 complete MMC cycle was on average 95 ± 12 min. Sixty percent of the first phases III and 40% of the second phases III had a gastric origin (p = 0.0574). Motilin (p < 0.05) plasma levels differed significantly between the phases of the MMC but total and octanoylated ghrelin did not. The percentage change in motilin during the MMC was dependent on the origin of phase III (p < 0.05). Motilin levels increased on average with 35 ± 10% right before a gastric phase III and with 3 ± 4% before a duodenal phase III (p < 0.05). The percentage change in total and octanoylated ghrelin plasma levels was not affected by the origin of phase III. CONCLUSIONS & INFERENCES These results confirm the role of motilin but not of ghrelin as an endogenous physiological regulator of the MMC with a gastric phase III.
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Affiliation(s)
- E Deloose
- Translational Research Centre for Gastrointestinal Disorders, University of Leuven, Leuven, Belgium
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Dudley ES, Grunden BK, Crocker C, Boivin GP. Incidence of dental lesions in musk shrews (Suncus murinus) and their association with sex, age, body weight and diet. Lab Anim (NY) 2013; 42:422-6. [PMID: 24150169 DOI: 10.1038/laban.408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 09/10/2013] [Indexed: 11/09/2022]
Abstract
Both wild and laboratory strains of the musk shrew (Suncus murinus) have a high incidence of periodontitis. The authors completed necropsy examinations in 51 shrews to identify dental lesions including tooth loss, mobility and fractures. Dental lesions were identified in significantly more females than males, and older animals were more likely to have lesions present. Shrews with one or more dental lesions weighed significantly less than those without lesions present. Dietary supplementation with mealworms did not significantly affect the incidence of dental lesions or the body weight of male or female shrews. The authors recommend routine body weight measurement as a simple, noninvasive method of detecting shrews with an increased likelihood of having dental lesions.
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Affiliation(s)
- Emily S Dudley
- Laboratory Animal Resources, Wright State University, Dayton, OH
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Miyano Y, Sakata I, Kuroda K, Aizawa S, Tanaka T, Jogahara T, Kurotani R, Sakai T. The role of the vagus nerve in the migrating motor complex and ghrelin- and motilin-induced gastric contraction in suncus. PLoS One 2013; 8:e64777. [PMID: 23724093 PMCID: PMC3665597 DOI: 10.1371/journal.pone.0064777] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 04/18/2013] [Indexed: 02/07/2023] Open
Abstract
The upper gastrointestinal (GI) tract undergoes a temporally coordinated cyclic motor pattern known as the migrating motor complex (MMC) in both dogs and humans during the fasted state. Feeding results in replacement of the MMC by a pattern of noncyclic, intermittent contractile activity termed as postprandial contractions. Although the MMC is known to be stimulated by motilin, recent studies have shown that ghrelin, which is from the same peptide family as motilin, is also involved in the regulation of the MMC. In the present study, we investigated the role of the vagus nerve on gastric motility using conscious suncus—a motilin- and ghrelin-producing small animal. During the fasted state, cyclic MMC comprising phases I, II, and III was observed in both sham-operated and vagotomized suncus; however, the duration and motility index (MI) of phase II was significantly decreased in vagotomized animals. Motilin infusion (50 ng·kg−1·min−1 for 10 min) during phase I had induced phase III–like contractions in both sham-operated and vagotomized animals. Ghrelin infusion (0.1, 0.3, 1, 3, or 10 µg·kg−1·min−1 for 10 min) enhanced the amplitude of phase II MMC in sham-operated animals, but not in vagotomized animals. After feeding, phase I was replaced by postprandial contractions, and motilin infusion (50 ng·kg−1·min−1 for 10 min) did not induce phase III–like contractions in sham-operated suncus. However, in vagotomized suncus, feeding did not evoke postprandial contractions, but exogenous motilin injection strongly induced phase III–like contractions, as noted during the phase I period. Thus, the results indicate that ghrelin stimulates phase II of the MMC via the vagus nerve in suncus. Furthermore, the vagus nerve is essential for initiating postprandial contractions, and inhibition of the phase III–like contractions induced by motilin is highly dependent on the vagus nerve.
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Affiliation(s)
- Yuki Miyano
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Ichiro Sakata
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
- * E-mail:
| | - Kayuri Kuroda
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Sayaka Aizawa
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Toru Tanaka
- Faculty of Pharmaceutical Sciences, Department of Pharmaceutical and Health Sciences, Josai University, Saitama, Japan
| | - Takamichi Jogahara
- Laboratory of Animal Management & Resources, Department of Zoology, Faculty of Science, Okayama University of Science, Okayama, Japan
| | - Reiko Kurotani
- Graduate School of Science and Engineering, Yamagata University, Yamagata, Japan
| | - Takafumi Sakai
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
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Mondal A, Aizawa S, Sakata I, Goswami C, Oda SI, Sakai T. Mechanism of ghrelin-induced gastric contractions in Suncus murinus (house musk shrew): involvement of intrinsic primary afferent neurons. PLoS One 2013; 8:e60365. [PMID: 23565235 PMCID: PMC3614873 DOI: 10.1371/journal.pone.0060365] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Accepted: 02/26/2013] [Indexed: 12/13/2022] Open
Abstract
Here, we have reported that motilin can induce contractions in a dose-dependent manner in isolated Suncus murinus (house musk shrew) stomach. We have also shown that after pretreatment with a low dose of motilin (10(-10) M), ghrelin also induces gastric contractions at levels of 10(-10) M to 10(-7) M. However, the neural mechanism of ghrelin action in the stomach has not been fully revealed. In the present study, we studied the mechanism of ghrelin-induced contraction in vitro using a pharmacological method. The responses to ghrelin in the stomach were almost completely abolished by hexamethonium and were significantly suppressed by the administration of phentolamine, prazosin, ondansetron, and naloxone. Additionally, N-nitro-l-arginine methylester significantly potentiated the contractions. Importantly, the mucosa is essential for ghrelin-induced, but not motilin-induced, gastric contractions. To evaluate the involvement of intrinsic primary afferent neurons (IPANs), which are multiaxonal neurons that pass signals from the mucosa to the myenteric plexus, we examined the effect of the IPAN-related pathway on ghrelin-induced contractions and found that pretreatment with adenosine and tachykinergic receptor 3 antagonists (SR142801) significantly eliminated the contractions and GR113808 (5-hydroxytryptamine receptor 4 antagonist) almost completely eliminated it. The results indicate that ghrelin stimulates and modulates suncus gastric contractions through cholinergic, adrenergic, serotonergic, opioidergic neurons and nitric oxide synthases in the myenteric plexus. The mucosa is also important for ghrelin-induced gastric contractions, and IPANs may be the important interneurons that pass the signal from the mucosa to the myenteric plexus.
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Affiliation(s)
- Anupom Mondal
- Area of Regulatory Biology, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Sayaka Aizawa
- Area of Regulatory Biology, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Ichiro Sakata
- Area of Regulatory Biology, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Chayon Goswami
- Area of Regulatory Biology, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Sen-ichi Oda
- Laboratory of Animal Management and Resources, Department of Zoology, Okayama University of Science, Okayama, Japan
| | - Takafumi Sakai
- Area of Regulatory Biology, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
- * E-mail:
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Suzuki A, Ishida Y, Aizawa S, Sakata I, Tsutsui C, Mondal A, Kanako K, Sakai T. Molecular identification of GHS-R and GPR38 in Suncus murinus. Peptides 2012; 36:29-38. [PMID: 22579813 DOI: 10.1016/j.peptides.2012.04.019] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Revised: 04/23/2012] [Accepted: 04/23/2012] [Indexed: 12/13/2022]
Abstract
We previously identified ghrelin and motilin genes in Suncus murinus (suncus), and also revealed that motilin induces phase III-like strong contractions in the suncus stomach in vivo, as observed in humans and dogs. Moreover, repeated migrating motor complexes were found in the gastrointestinal tract of suncus at regular 120-min intervals. We therefore proposed suncus as a small laboratory animal model for the study of gastrointestinal motility. In the present study, we identified growth hormone secretagogue receptor (GHS-R) and motilin receptor (GPR38) genes in the suncus. We also examined their tissue distribution throughout the body. The amino acids of suncus GHS-R and GPR38 showed high homology with those of other mammals and shared 42% amino acid identity. RT-PCR showed that both the receptors were expressed in the hypothalamus, medulla oblongata, pituitary gland and the nodose ganglion in the central nervous system. In addition, GHS-R mRNA expressions were detected throughout the stomach and intestine, whereas GPR38 was expressed in the gastric muscle layer, lower intestine, lungs, heart, and pituitary gland. These results suggest that ghrelin and motilin affect gut motility and energy metabolism via specific receptors expressed in the gastrointestinal tract and/or in the central nervous system of suncus.
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Affiliation(s)
- Airi Suzuki
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Sakura-ku, Saitama, Japan
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Mondal A, Xie Z, Miyano Y, Tsutsui C, Sakata I, Kawamoto Y, Aizawa S, Tanaka T, Oda SI, Sakai T. Coordination of motilin and ghrelin regulates the migrating motor complex of gastrointestinal motility in Suncus murinus. Am J Physiol Gastrointest Liver Physiol 2012; 302:G1207-15. [PMID: 22383491 DOI: 10.1152/ajpgi.00379.2011] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Motilin and ghrelin are the gastrointestinal (GI) hormones released in a fasting state to stimulate the GI motility of the migrating motor complex (MMC). We focused on coordination of the ghrelin/motilin family in gastric contraction in vivo and in vitro using the house musk shrew (Suncus murinus), a ghrelin- and motilin-producing mammal. To measure the contractile activity of the stomach in vivo, we recorded GI contractions either in the free-moving conscious or anesthetized S. murinus and examined the effects of administration of motilin and/or ghrelin on spontaneous MMC in the fasting state. In the in vitro study, we also studied the coordinative effect of these hormones on the isolated stomach using an organ bath. In the fasting state, phase I, II, and III contractions were clearly recorded in the gastric body (as observed in humans and dogs). Intravenous infusion of ghrelin stimulated gastric contraction in the latter half of phase I and in the phase II in a dose-dependent manner. Continuous intravenous infusion of ghrelin antagonist (d-Lys3-GHRP6) significantly suppressed spontaneous phase II contractions and prolonged the time of occurrence of the peak of phase III contractions. However, intravenous infusion of motilin antagonist (MA-2029) did not inhibit phase II contractions but delayed the occurrence of phase III contractions of the MMC. In the in vitro study, even though a high dose of ghrelin did not stimulate contraction of stomach preparations, ghrelin administration (10(-10)-10(-7) M) with pretreatment of a low dose of motilin (10(-10) M) induced gastric contraction in a dose-dependent manner. Pretreatment with 10(-8) M ghrelin enhanced motilin-stimulated gastric contractions by 10 times. The interrelation of these peptides was also demonstrated in the anesthetized S. murinus. The results suggest that ghrelin is important for the phase II contraction and that coordination of motilin and ghrelin are necessary to initiate phase III contraction of the MMC.
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Affiliation(s)
- Anupom Mondal
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan
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Shiina T, Shima T, Suzuki Y, Wörl J, Shimizu Y. Neural regulation of esophageal striated muscle in the house musk shrew (Suncus murinus). Auton Neurosci 2012; 168:25-31. [PMID: 22285704 DOI: 10.1016/j.autneu.2012.01.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Revised: 01/05/2012] [Accepted: 01/08/2012] [Indexed: 12/21/2022]
Abstract
In the present study, we characterized the neural regulation of esophageal striated muscle in Suncus murinus (a house musk shrew; "suncus" used as a laboratory name), which was compared with that in the rat. The tunica muscularis consists of striated muscle in the suncus esophagus. An isolated segment of the suncus esophagus was placed in an organ bath and the contractile responses were recorded using a force transducer. Electrical stimulations to vagus nerves induced contractile responses in the esophageal segment. Treatment with α-bungarotoxin, a blocker of nicotinic acetylcholine receptors, blocked the vagally mediated contractions of the suncus esophagus. D-tubocurarine and succinylcholine, typical antagonists of nicotinic acetylcholine receptors, also inhibited the suncus esophageal contractions, while higher concentrations of the agents were required rather than concentrations for producing an equivalent block in the rat. We used capsaicin, a stimulator of small-caliber afferent neurons, for activating the peripheral neural network. The reagent inhibited the vagally mediated twitch contractions of striated muscle in the suncus esophagus, which was reversed by pretreatment with a nitric oxide synthase inhibitor, N(G)-nitro-L-arginine methyl ester. Application of a nitric oxide donor, diethylamine NONOate diethylammonium salt, mimicked capsaicin-induced inhibition. The results suggest that motility of the suncus esophagus, which consists of striated muscles, is regulated by vagal cholinergic neurons. The local neural network including capsaicin-sensitive neurons and intrinsic nitrergic neurons can modify the vagally mediated motility in the suncus esophagus. In addition, nicotinic acetylcholine receptors of the suncus esophagus might be pharmacologically distinct from those of rodent esophagi.
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Affiliation(s)
- Takahiko Shiina
- Laboratory of Physiology, Department of Basic Veterinary Science, The United Graduate School of Veterinary Sciences, Gifu University, Japan.
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Abstract
Ghrelin is a potent stimulant for gastric emptying and gastrointestinal (GI) movement. Clinically, it has been reported that the intravenous administration of ghrelin accelerates the rate of gastric emptying and induces gastric phase III contractions of the migrating motor complex in healthy volunteers. Recent technical advances in the measurement of GI motility in conscious small animals, including rats, mice, and the house musk shrew (Suncus murinus), have helped to elucidate the precise mechanism of action of ghrelin. Intravenous administration of ghrelin induces fasted motor activities with phase III-like contractions of the migrating motor complex in the antrum and duodenum in animals. These effects of ghrelin are mediated by activating the hypothalamic orexigenic neuropeptide Y neuron through ghrelin receptors located at the vagal afferent terminal. Stress hormone and anorexigenic peptides cause the disruption of fasted motor activity and induce fed-like motor activity. Ghrelin and the ghrelin signal potentiator rikkunshito successfully restore fed-like motor activities to fasted activities in fenfluramine-treated rats and in a cancer anorexia-cachexia animal model. These findings suggest that ghrelin can be expected to be a therapeutic target for GI disorders.
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Mondal A, Kawamoto Y, Yanaka T, Tsutsui C, Sakata I, Oda SI, Tanaka T, Sakai T. Myenteric neural network activated by motilin in the stomach of Suncus murinus (house musk shrew). Neurogastroenterol Motil 2011; 23:1123-31. [PMID: 22029733 DOI: 10.1111/j.1365-2982.2011.01801.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND It has been shown in human and canine studies that motilin, a gastroprokinetic hormone, induces gastric phase III contractions via the enteric nervous; however, the center of motilin action in the stomach has not been clearly revealed. In the present study, we investigated the neural pathway of motilin-induced gastric contraction by using Suncus murinus, a new animal model for motilin study. METHODS An isolated suncus stomach was used in vitro to determine the mechanism of motilin action through the myenteric plexus. Synthetic suncus motilin (10(-11) -10(-7) molL(-1) ) was added to an organ bath, and the spontaneous contraction response was expressed as a percent of ACh (10(-5) molL(-1) ) responses. Motilin-induced contractions were also studied by a pharmacological method using several receptor antagonists and enzyme inhibitor. KEY RESULTS Suncus motilin induced a concentration-dependent gastric contraction at concentrations from 10(-9) to 10(-7) molL(-1) . The responses to suncus motilin in the stomach were completely abolished by atropine and tetrodotoxin treatment and significantly suppressed by administration of hexamethonium, verapamil, phentolamine, yohimbine, ondansetron, and naloxone, whereas ritanserin, prazosin, timolol, and FK888 did not affect the action of motilin. Additionally, N-nitro l-arginine methylester slightly potentiated the contractions induced by motilin. CONCLUSIONS & INFERENCES The results indicate that motilin directly stimulates and modulates suncus gastric contraction through cholinergic, adrenergic, serotonergic, opioidergic, and NO neurons in the myenteric plexus.
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Affiliation(s)
- A Mondal
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Sakura-ku, Saitama, Japan
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