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Li YH, Jiang ZX, Xu Q, Jin TT, Huang JF, Luan X, Li C, Chen XY, Wong KH, Dong XL, Sun XR. Inhibition of calcium-sensing receptor by its antagonist promotes gastrointestinal motility in a Parkinson's disease mouse model. Biomed Pharmacother 2024; 174:116518. [PMID: 38565057 DOI: 10.1016/j.biopha.2024.116518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 03/26/2024] [Accepted: 03/28/2024] [Indexed: 04/04/2024] Open
Abstract
BACKGROUND The Calcium-sensing receptor (CaSR) participates in the regulation of gastrointestinal (GI) motility under normal conditions and might be involved in the regulation of GI dysmotility in patients with Parkinson's disease (PD). METHODS CaSR antagonist-NPS-2143 was applied in in vivo and ex vivo experiments to study the effect and underlying mechanisms of CaSR inhibition on GI dysmotility in the MPTP-induced PD mouse model. FINDINGS Oral intake of NPS-2143 promoted GI motility in PD mice as shown by the increased gastric emptying rate and shortened whole gut transit time together with improved weight and water content in the feces of PD mice, and the lack of influence on normal mice. Meanwhile, the number of cholinergic neurons, the proportion of serotonergic neurons, as well as the levels of acetylcholine and serotonin increased, but the numbers of nitrergic and tyrosine hydroxylase immunoreactive neurons, and the levels of nitric oxide synthase and dopamine decreased in the myenteric plexus in the gastric antrum and colon of PD mice in response to NPS-2143 treatment. Furthermore, the numbers of c-fos positive neurons in the nucleus tractus solitarius (NTS) and cholinergic neurons in the dorsal motor nucleus of the vagus (DMV) increased in NPS-2143 treated PD mice, suggesting the involvement of both the enteric (ENS) and central (CNS) nervous systems. However, ex vivo results showed that NPS-2143 directly inhibited the contractility of antral and colonic strips in PD mice via a non-ENS mediated mechanism. Further studies revealed that NPS-2143 directly inhibited the voltage gated Ca2+ channels, which might, at least in part, explain its direct inhibitory effects on the GI muscle strips. INTERPRETATION CaSR inhibition by its antagonist ameliorated GI dysmotility in PD mice via coordinated neuronal regulation by both ENS and CNS in vivo, although the direct effects of CaSR inhibition on GI muscle strips were suppressive.
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Affiliation(s)
- Yu-Hang Li
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, Shandong, China
| | - Zhong-Xin Jiang
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, Shandong, China; Department of Clinical Laboratory, the Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Qian Xu
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, Shandong, China
| | - Ting-Ting Jin
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, Shandong, China; Department of Pathology, Women's and Children's Hospital Affiliated to Qingdao University, Qingdao, Shandong, China
| | - Jin-Fang Huang
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, Shandong, China; Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Xiao Luan
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, Shandong, China
| | - Chong Li
- Research Institute for Future Food, The Hong Kong Polytechnic University, Hong Kong, China; Department of Food Science and Nutrition, The Hong Kong Polytechnic University, Hong Kong, China
| | - Xin-Yi Chen
- Department of International Medicine, Affiliated Hospital of Qingdao University, Qingdao, China
| | - Ka-Hing Wong
- Research Institute for Future Food, The Hong Kong Polytechnic University, Hong Kong, China; Department of Food Science and Nutrition, The Hong Kong Polytechnic University, Hong Kong, China.
| | - Xiao-Li Dong
- Research Institute for Future Food, The Hong Kong Polytechnic University, Hong Kong, China; Department of Food Science and Nutrition, The Hong Kong Polytechnic University, Hong Kong, China.
| | - Xiang-Rong Sun
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, Shandong, China.
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Tang N, Li Y, Li Y, Xu S, Wang M, Wang B, Liu Y, Zhang S, Wu H, Zhang X, Zhou B, Li Z. Motilin, a Novel Orexigenic Factor, Involved in Feeding Regulation in Yangtze Sturgeon ( Acipenser dabryanus). Biomolecules 2024; 14:433. [PMID: 38672450 PMCID: PMC11048545 DOI: 10.3390/biom14040433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 03/19/2024] [Accepted: 03/27/2024] [Indexed: 04/28/2024] Open
Abstract
Motilin is a gastrointestinal hormone that is mainly produced in the duodenum of mammals, and it is responsible for regulating appetite. However, the role and expression of motilin are poorly understood during starvation and the weaning stage, which is of great importance in the seeding cultivation of fish. In this study, the sequences of Yangtze sturgeon (Acipenser dabryanus Motilin (AdMotilin)) motilin receptor (AdMotilinR) were cloned and characterized. The results of tissue expression showed that by contrast with mammals, AdMotilin mRNA was richly expressed in the brain, whereas AdMotilinR was highly expressed in the stomach, duodenum, and brain. Weaning from a natural diet of T. Limnodrilus to commercial feed significantly promoted the expression of AdMotilin in the brain during the period from day 1 to day 10, and after re-feeding with T. Limnodrilus the change in expression of AdMotilin was partially reversed. Similarly, it was revealed that fasting increased the expression of AdMotilin in the brain (3 h, 6 h) and duodenum (3 h), and the expression of AdMotilinR in the brain (1 h) in a time-dependent manner. Furthermore, it was observed that peripheral injection of motilin-NH2 increased food intake and the filling index of the digestive tract in the Yangtze sturgeon, which was accompanied by the changes of AdMotilinR and appetite factors expression in the brain (POMC, CART, AGRP, NPY and CCK) and stomach (CCK). These results indicate that motilin acts as an indicator of nutritional status, and also serves as a novel orexigenic factor that stimulates food intake in Acipenser dabryanus. This study lays a strong foundation for the application of motilin as a biomarker in the estimation of hunger in juvenile Acipenser dabryanu during the weaning phase, and enhances the understanding of the role of motilin as a novel regulator of feeding in fish.
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Affiliation(s)
- Ni Tang
- Department of Aquaculture, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China; (N.T.); (Y.L.); (Y.L.); (S.X.); (M.W.); (Y.L.); (S.Z.); (H.W.); (X.Z.)
| | - Ya Li
- Department of Aquaculture, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China; (N.T.); (Y.L.); (Y.L.); (S.X.); (M.W.); (Y.L.); (S.Z.); (H.W.); (X.Z.)
| | - Yingzi Li
- Department of Aquaculture, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China; (N.T.); (Y.L.); (Y.L.); (S.X.); (M.W.); (Y.L.); (S.Z.); (H.W.); (X.Z.)
| | - Shaoqi Xu
- Department of Aquaculture, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China; (N.T.); (Y.L.); (Y.L.); (S.X.); (M.W.); (Y.L.); (S.Z.); (H.W.); (X.Z.)
| | - Mei Wang
- Department of Aquaculture, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China; (N.T.); (Y.L.); (Y.L.); (S.X.); (M.W.); (Y.L.); (S.Z.); (H.W.); (X.Z.)
| | - Bin Wang
- Fisheries Research Institute, Sichuan Academy of Agricultural Sciences, Chengdu 610066, China;
| | - Yanling Liu
- Department of Aquaculture, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China; (N.T.); (Y.L.); (Y.L.); (S.X.); (M.W.); (Y.L.); (S.Z.); (H.W.); (X.Z.)
| | - Shupeng Zhang
- Department of Aquaculture, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China; (N.T.); (Y.L.); (Y.L.); (S.X.); (M.W.); (Y.L.); (S.Z.); (H.W.); (X.Z.)
| | - Hongwei Wu
- Department of Aquaculture, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China; (N.T.); (Y.L.); (Y.L.); (S.X.); (M.W.); (Y.L.); (S.Z.); (H.W.); (X.Z.)
| | - Xin Zhang
- Department of Aquaculture, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China; (N.T.); (Y.L.); (Y.L.); (S.X.); (M.W.); (Y.L.); (S.Z.); (H.W.); (X.Z.)
| | - Bo Zhou
- Fisheries Research Institute, Sichuan Academy of Agricultural Sciences, Chengdu 610066, China;
| | - Zhiqiong Li
- Department of Aquaculture, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China; (N.T.); (Y.L.); (Y.L.); (S.X.); (M.W.); (Y.L.); (S.Z.); (H.W.); (X.Z.)
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Wen X, Dong H, Zou W. The role of gut microorganisms and metabolites in intracerebral hemorrhagic stroke: a comprehensive review. Front Neurosci 2024; 18:1346184. [PMID: 38449739 PMCID: PMC10915040 DOI: 10.3389/fnins.2024.1346184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 02/09/2024] [Indexed: 03/08/2024] Open
Abstract
Intracerebral hemorrhagic stroke, characterized by acute hemorrhage in the brain, has a significant clinical prevalence and poses a substantial threat to individuals' well-being and productivity. Recent research has elucidated the role of gut microorganisms and their metabolites in influencing brain function through the microbiota-gut-brain axis (MGBA). This article provides a comprehensive review of the current literature on the common metabolites, short-chain fatty acids (SCFAs) and trimethylamine-N-oxide (TMAO), produced by gut microbiota. These metabolites have demonstrated the potential to traverse the blood-brain barrier (BBB) and directly impact brain tissue. Additionally, these compounds have the potential to modulate the parasympathetic nervous system, thereby facilitating the release of pertinent substances, impeding the buildup of inflammatory agents within the brain, and manifesting anti-inflammatory properties. Furthermore, this scholarly analysis delves into the existing dearth of investigations concerning the influence of gut microorganisms and their metabolites on cerebral functions, while also highlighting prospective avenues for future research.
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Affiliation(s)
- Xin Wen
- The First Clinical Medical College, Heilongjiang University Of Chinese Medicine, Harbin, China
| | - Hao Dong
- The First Clinical Medical College, Heilongjiang University Of Chinese Medicine, Harbin, China
| | - Wei Zou
- The First Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, China
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Sanger GJ. Why is motilin active in some studies with mice, rats, and guinea pigs, but not in others? Implications for functional variability among rodents. Pharmacol Res Perspect 2022; 10:e00900. [PMID: 35191209 PMCID: PMC8860775 DOI: 10.1002/prp2.900] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 11/19/2021] [Indexed: 11/17/2022] Open
Abstract
The gastrointestinal (GI) hormone motilin helps control human stomach movements during hunger and promotes hunger. Although widely present among mammals, it is generally accepted that in rodents the genes for motilin and/or its receptor have undergone pseudonymization, so exogenous motilin cannot function. However, several publications describe functions of low concentrations of motilin, usually within the GI tract and CNS of mice, rats, and guinea pigs. These animals were from institute-held stocks, simply described with stock names (e.g., "Sprague-Dawley") or were inbred strains. It is speculated that variation in source/type of animal introduces genetic variations to promote motilin-sensitive pathways. Perhaps, in some populations, motilin receptors exist, or a different functionally-active receptor has a good affinity for motilin (indicating evolutionary pressures to retain motilin functions). The ghrelin receptor has the closest sequence homology, yet in non-rodents the receptors have a poor affinity for each other's cognate ligand. In rodents, ghrelin may substitute for certain GI functions of motilin, but no good evidence suggests rodent ghrelin receptors are highly responsive to motilin. It remains unknown if motilin has functional relationships with additional bioactive molecules formed from the ghrelin and motilin genes, or if a 5-TM motilin receptor has influence in rodents (e.g., to dimerize with GPCRs and create different pharmacological profiles). Is the absence/presence of responses to motilin in rodents' characteristic for systems undergoing gene pseudonymization? What are the consequences of rodent supplier-dependent variations in motilin sensitivity (or other ligands for receptors undergoing pseudonymization) on gross physiological functions? These are important questions for understanding animal variation.
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Affiliation(s)
- Gareth J. Sanger
- Blizard Institute and the National Centre for Bowel ResearchBarts and The London School of Medicine and DentistryQueen Mary University of LondonLondonUnited Kingdom
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Zhao Q, Chen YY, Xu DQ, Yue SJ, Fu RJ, Yang J, Xing LM, Tang YP. Action Mode of Gut Motility, Fluid and Electrolyte Transport in Chronic Constipation. Front Pharmacol 2021; 12:630249. [PMID: 34385914 PMCID: PMC8353128 DOI: 10.3389/fphar.2021.630249] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 06/28/2021] [Indexed: 12/12/2022] Open
Abstract
Chronic constipation is a common gastrointestinal disorder, with a worldwide incidence of 14–30%. It negatively affects quality of life and is associated with a considerable economic burden. As a disease with multiple etiologies and risk factors, it is important to understand the pathophysiology of chronic constipation. The purpose of this review is to discuss latest findings on the roles of gut motility, fluid, and electrolyte transport that contribute to chronic constipation, and the main drugs available for treating patients. We conducted searches on PubMed and Google Scholar up to 9 February 2021. MeSH keywords “constipation”, “gastrointestinal motility”, “peristalsis”, “electrolytes”, “fluid”, “aquaporins”, and “medicine” were included. The reference lists of searched articles were reviewed to identify further eligible articles. Studies focusing on opioid-induced constipation, evaluation, and clinic management of constipation were excluded. The occurrence of constipation is inherently connected to disorders of gut motility as well as fluid and electrolyte transport, which involve the nervous system, endocrine signaling, the gastrointestinal microbiota, ion channels, and aquaporins. The mechanisms of action and application of the main drugs are summarized; a better understanding of ion channels and aquaporins may be helpful for new drug development. This review aims to provide a scientific basis that can guide future research on the etiology and treatment of constipation.
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Affiliation(s)
- Qi Zhao
- Key Laboratory of Shaanxi Administration of Traditional Chinese Medicine for TCM Compatibility, and State Key Laboratory of Research and Development of Characteristic Qin Medicine Resources (Cultivation), and Shaanxi Key Laboratory of Chinese Medicine Fundamentals and New Drugs Research, Shaanxi University of Chinese Medicine, Xi'an, China
| | - Yan-Yan Chen
- Key Laboratory of Shaanxi Administration of Traditional Chinese Medicine for TCM Compatibility, and State Key Laboratory of Research and Development of Characteristic Qin Medicine Resources (Cultivation), and Shaanxi Key Laboratory of Chinese Medicine Fundamentals and New Drugs Research, Shaanxi University of Chinese Medicine, Xi'an, China
| | - Ding-Qiao Xu
- Key Laboratory of Shaanxi Administration of Traditional Chinese Medicine for TCM Compatibility, and State Key Laboratory of Research and Development of Characteristic Qin Medicine Resources (Cultivation), and Shaanxi Key Laboratory of Chinese Medicine Fundamentals and New Drugs Research, Shaanxi University of Chinese Medicine, Xi'an, China
| | - Shi-Jun Yue
- Key Laboratory of Shaanxi Administration of Traditional Chinese Medicine for TCM Compatibility, and State Key Laboratory of Research and Development of Characteristic Qin Medicine Resources (Cultivation), and Shaanxi Key Laboratory of Chinese Medicine Fundamentals and New Drugs Research, Shaanxi University of Chinese Medicine, Xi'an, China
| | - Rui-Jia Fu
- Key Laboratory of Shaanxi Administration of Traditional Chinese Medicine for TCM Compatibility, and State Key Laboratory of Research and Development of Characteristic Qin Medicine Resources (Cultivation), and Shaanxi Key Laboratory of Chinese Medicine Fundamentals and New Drugs Research, Shaanxi University of Chinese Medicine, Xi'an, China
| | - Jie Yang
- Key Laboratory of Shaanxi Administration of Traditional Chinese Medicine for TCM Compatibility, and State Key Laboratory of Research and Development of Characteristic Qin Medicine Resources (Cultivation), and Shaanxi Key Laboratory of Chinese Medicine Fundamentals and New Drugs Research, Shaanxi University of Chinese Medicine, Xi'an, China
| | - Li-Ming Xing
- Key Laboratory of Shaanxi Administration of Traditional Chinese Medicine for TCM Compatibility, and State Key Laboratory of Research and Development of Characteristic Qin Medicine Resources (Cultivation), and Shaanxi Key Laboratory of Chinese Medicine Fundamentals and New Drugs Research, Shaanxi University of Chinese Medicine, Xi'an, China
| | - Yu-Ping Tang
- Key Laboratory of Shaanxi Administration of Traditional Chinese Medicine for TCM Compatibility, and State Key Laboratory of Research and Development of Characteristic Qin Medicine Resources (Cultivation), and Shaanxi Key Laboratory of Chinese Medicine Fundamentals and New Drugs Research, Shaanxi University of Chinese Medicine, Xi'an, China
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Hong SW, Chun J, Kim J, Lee J, Lee HJ, Chung H, Cho SJ, Im JP, Kim SG, Kim JS. Efficacy and Safety of Ghrelin Agonists in Patients with Diabetic Gastroparesis: A Systematic Review and Meta-Analysis. Gut Liver 2020; 14:589-600. [PMID: 31816671 PMCID: PMC7492501 DOI: 10.5009/gnl19103] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 09/20/2019] [Accepted: 09/22/2019] [Indexed: 12/15/2022] Open
Abstract
Background/Aims Ghrelin agonists are emerging prokinetic agents for treating gastroparesis. Although recent clinical trials have demonstrated their efficacy in patients with diabetic gastroparesis (DG), the impact of such agents on symptoms and gastric dysmotility remains unclear. We performed a systematic review and meta-analysis to evaluate the efficacy and safety of ghrelin agonists in patients with DG. Methods A search of common electronic databases (MEDLINE, Embase, and Cochrane Central Register of Controlled Trials) was preformed, using keyword combinations that referenced ghrelin and DG and retrieving all eligible randomized controlled trials (RCTs) of ghrelin agonists versus placebo in patients with DG. The primary outcome measure was the change in patient-reported overall gastroparesis symptom scores. Secondary outcomes included the change in gastric emptying time, specific symptoms related to gastroparesis, and adverse events. A random-effects model was applied to all study outcomes. Heterogeneity among studies was determined by the chi-square test and I2 statistics. Results We selected six RCTs of patients with DG (n=557) for meta-analysis. Ghrelin agonist administration (vs placebo) significantly improved overall gastroparesis symptoms (standardized mean difference, –0.34; 95% confidence interval, –0.56 to –0.13) and significantly improved symptoms related to gastroparesis, including nausea, vomiting, early satiety, and abdominal pain. Adverse events recorded for ghrelin agonists and placebo did not differ significantly. There was no significant heterogeneity among eligible studies. Conclusions Compared with placebo, ghrelin agonists are effective and well-tolerated for the treatment of DG.
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Affiliation(s)
- Seung Wook Hong
- Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | - Jaeyoung Chun
- Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea.,Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Jihye Kim
- Department of Internal Medicine, CHA Gangnam Medical Center, CHA University School of Medicine, Seoul, Korea
| | - Jooyoung Lee
- Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | - Hyun Jung Lee
- Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | - Hyunsoo Chung
- Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | - Soo-Jeong Cho
- Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | - Jong Pil Im
- Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | - Sang Gyun Kim
- Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | - Joo Sung Kim
- Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea
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Fleming MA, Ehsan L, Moore SR, Levin DE. The Enteric Nervous System and Its Emerging Role as a Therapeutic Target. Gastroenterol Res Pract 2020; 2020:8024171. [PMID: 32963521 PMCID: PMC7495222 DOI: 10.1155/2020/8024171] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/03/2020] [Accepted: 08/24/2020] [Indexed: 02/08/2023] Open
Abstract
The gastrointestinal (GI) tract is innervated by the enteric nervous system (ENS), an extensive neuronal network that traverses along its walls. Due to local reflex circuits, the ENS is capable of functioning with and without input from the central nervous system. The functions of the ENS range from the propulsion of food to nutrient handling, blood flow regulation, and immunological defense. Records of it first being studied emerged in the early 19th century when the submucosal and myenteric plexuses were discovered. This was followed by extensive research and further delineation of its development, anatomy, and function during the next two centuries. The morbidity and mortality associated with the underdevelopment, infection, or inflammation of the ENS highlight its importance and the need for us to completely understand its normal function. This review will provide a general overview of the ENS to date and connect specific GI diseases including short bowel syndrome with neuronal pathophysiology and current therapies. Exciting opportunities in which the ENS could be used as a therapeutic target for common GI diseases will also be highlighted, as the further unlocking of such mechanisms could open the door to more therapy-related advances and ultimately change our treatment approach.
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Affiliation(s)
- Mark A. Fleming
- Department of Surgery, Division of Pediatric Surgery, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Lubaina Ehsan
- Department of Pediatrics, Division of Pediatric Gastroenterology, Hepatology, and Nutrition, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Sean R. Moore
- Department of Pediatrics, Division of Pediatric Gastroenterology, Hepatology, and Nutrition, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Daniel E. Levin
- Department of Surgery, Division of Pediatric Surgery, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
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Deloose E, Verbeure W, Depoortere I, Tack J. Motilin: from gastric motility stimulation to hunger signalling. Nat Rev Endocrinol 2019; 15:238-250. [PMID: 30675023 DOI: 10.1038/s41574-019-0155-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
After the discovery of motilin in 1972, motilin and the motilin receptor were studied intensely for their role in the control of gastrointestinal motility and as targets for treating hypomotility disorders. The genetic revolution - with the use of knockout models - sparked novel insights into the role of multiple peptides but contributed to a decline in interest in motilin, as this peptide and its receptor exist only as pseudogenes in rodents. The past 5 years have seen a major surge in interest in motilin, as a series of studies have shown its relevance in the control of hunger and regulation of food intake in humans in both health and disease. Luminal stimuli, such as bitter tastants, have been identified as modulators of motilin release, with effects on hunger and food intake. The current state of knowledge and potential implications for therapy are summarized in this Review.
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Affiliation(s)
- Eveline Deloose
- Translational Research in Gastrointestinal Disorders (TARGID), Department of Chronic Diseases, Metabolism and Ageing (CHROMETA), KU Leuven, Leuven, Belgium
| | - Wout Verbeure
- Translational Research in Gastrointestinal Disorders (TARGID), Department of Chronic Diseases, Metabolism and Ageing (CHROMETA), KU Leuven, Leuven, Belgium
| | - Inge Depoortere
- Translational Research in Gastrointestinal Disorders (TARGID), Department of Chronic Diseases, Metabolism and Ageing (CHROMETA), KU Leuven, Leuven, Belgium
| | - Jan Tack
- Translational Research in Gastrointestinal Disorders (TARGID), Department of Chronic Diseases, Metabolism and Ageing (CHROMETA), KU Leuven, Leuven, Belgium.
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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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Miron I, Dumitrascu DL. GASTROINTESTINAL MOTILITY DISORDERS IN OBESITY. ACTA ENDOCRINOLOGICA-BUCHAREST 2019; 15:497-504. [PMID: 32377248 DOI: 10.4183/aeb.2019.497] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The gastrointestinal (GI) motility, which is important for the digestion and absorption, may be altered in obesity. The aim of this review is to present the GI motility changes occurring in obesity, as well as their underlying mechanisms. We have conducted a systematic review of the published literature concerning GI motility and obesity and have described recent published data on the changes throughout the entire GI tract. Most recent discoveries include evidence supporting the increase of gastroesophageal reflux disease in obesity and inhibition of gastric motility. Intestinal transit of the distal small bowel generally slows down, ensuring enough time for digestion and absorption. Constipation is more frequent in obese patients than in those with a normal weight. The gut-brain axis plays an important role in the pathophysiology of GI motility disorders in obesity. This bidirectional communication is achieved by way of neurons, hormones, metabolites derived from intestinal microbiota and cytokines. The molecular mechanisms of GI motility changes in obesity are complex. Current data offer a starting point for further research needed to clarify the association of obesity with GI motility disorders.
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Affiliation(s)
- I Miron
- "Iuliu Hatieganu" University of Medicine and Pharmacy, 3 Medical Clinic, Cluj-Napoca, Romania
| | - D L Dumitrascu
- "Iuliu Hatieganu" Dept of Internal Medicine, Cluj-Napoca, Romania
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11
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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: 45] [Impact Index Per Article: 9.0] [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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12
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Green BD, Grieve DJ. Biochemical properties and biological actions of obestatin and its relevence in type 2 diabetes. Peptides 2018; 100:249-259. [PMID: 29412827 DOI: 10.1016/j.peptides.2017.12.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 12/05/2017] [Accepted: 12/06/2017] [Indexed: 12/15/2022]
Abstract
Obestatin was initially discovered in rat stomach extract, and although it is principally produced in the gastric mucosa, it can be found throughout the gastrointestinal tract. This 23-amino acid C-terminally amidated peptide is derived from preproghrelin and has been ascribed a wide range of metabolic effects relevant to type 2 diabetes. Obestatin reportedly inhibits gastrointestinal motility, reduces food intake and lowers body weight and improves lipid metabolism. Furthermore, it appears to exert actions on the pancreatic β-cell, most notably increasing β-cell mass and upregulating genes associated with insulin production and β-cell regeneration, with relevance to type 2 diabetes. It is becoming evident that obestatin also exerts pleiotropic effects on the cardiovascular system, possibly modulating blood pressure, endothelial function and triggering cardioprotective mechanisms, which may be important in determining cardiovascular outcomes in type 2 diabetes. Furthermore, it seems that like other gut peptides obestatin has neuroprotective properties. This review examines the biochemical properties of the obestatin peptide (its structure, sequence, stability and distribution) and the candidate receptors through which it may act. It provides a balanced examination of the reported pancreatic and extrapancreatic actions of obestatin and evaluates its potential relevance with respect to diabetes therapy, together with discussion of direct evidence linking alterations in obestatin signalling with obesity/diabetes and other diseases.
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Affiliation(s)
- Brian D Green
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast, BT9 5BN, UK.
| | - David J Grieve
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, BT9 7AE, UK
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Deloose E, Depoortere I, de Hoon J, Van Hecken A, Dewit OE, Vasist Johnson LS, Barton ME, Dukes GE, Tack J. Manometric evaluation of the motilin receptor agonist camicinal (GSK962040) in humans. Neurogastroenterol Motil 2018; 30. [PMID: 28782145 DOI: 10.1111/nmo.13173] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 06/30/2017] [Indexed: 12/12/2022]
Abstract
BACKGROUND The gut hormone motilin stimulates gastrointestinal motility by inducing gastric phase III of the migrating motor complex (MMC) and enhancing the rate of gastric emptying. Camicinal (GSK962040), a small molecule motilin receptor agonist, has been shown to increase gastrointestinal motility. METHODS In this proof of concept study the effects of camicinal on MMC activity, esophageal and gastric pH was evaluated in eight healthy volunteers as a secondary endpoint. Doses of 50 and 150 mg were compared to placebo for a period of 24 hours in a double-blinded randomized crossover trial. KEY RESULTS The 50 mg dose (n=4) of camicinal had no significant impact on gastroduodenal manometry or pH parameters. A single dose of 150 mg (n=4) induced a gastric phase III after 0:34 h (0:25-0:58), which was significantly faster compared to placebo (18:15 h (4:32-22:16); P=.03). Moreover, the high dose significantly increased the occurrence of gastric phase III contractions compared to placebo (12% vs 39%; P=.0003). This increase in gastric phase III contractions during a period of 24 hour was due to an increased occurrence of gastric phases III during the daytime (5% vs 50%; P=.0001). The same dose however did not affect small bowel manometry parameters or esophageal and gastric pH. CONCLUSIONS AND INFERENCES Considering its stimulating effect on the MMC and gastric emptying, camicinal is an attractive candidate for the treatment of gastroparesis and gastroesophageal reflux disease. This trial was registered at clinicaltrials.gov as NCT00562848.
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Affiliation(s)
- E Deloose
- KU Leuven (University of Leuven), TARGID, Leuven, Belgium
| | - I Depoortere
- KU Leuven (University of Leuven), TARGID, Leuven, Belgium
| | - J de Hoon
- KU Leuven (University of Leuven), Center for Clinical Pharmacology, Leuven, Belgium
| | - A Van Hecken
- KU Leuven (University of Leuven), Center for Clinical Pharmacology, Leuven, Belgium
| | - O E Dewit
- GSK Research and Development, GSK, Cambridge, UK
| | | | - M E Barton
- GSK Research and Development, GSK, Research Triangle Park, NC, USA
| | - G E Dukes
- GSK Research and Development, GSK, Research Triangle Park, NC, USA
| | - J Tack
- KU Leuven (University of Leuven), TARGID, Leuven, Belgium
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14
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Okuhara Y, Kaiya H, Teraoka H, Kitazawa T. Structural determination, distribution, and physiological actions of ghrelin in the guinea pig. Peptides 2018; 99:70-81. [PMID: 29183755 DOI: 10.1016/j.peptides.2017.11.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Revised: 11/20/2017] [Accepted: 11/20/2017] [Indexed: 12/13/2022]
Abstract
We identified guinea pig ghrelin (gp-ghrelin), and examined its distribution and physiological actions in the guinea-pig. Gp-ghrelin is a 28-amino acid peptide (GASFR SPEHH SAQQR KESRK LPAKI QPR); seven amino acids are different from that of rat ghrelin at positions 2, 5, 10, 11, 19, 21, and 25, which include the conserved region known in mammals. The third serine residue is mainly modified by n-decanoyl acid. Both gp-ghrelin and rat ghrelin increased intracellular Ca2+ concentration of HEK293 cells expressing guinea pig growth hormone secretagogue receptor 1a (GHS-R1a), and the affinity of gp-ghrelin was slightly higher than that of rat ghrelin. In addition, gp-ghrelin was also effective in CHO cells expressing rat GHS-R1a with similar affinity to that of rat ghrelin. Gp-ghrelin mRNA was predominantly expressed in the stomach, whereas the expression levels in other organs was low. High levels of GHS-R1a mRNA expression were observed in the pituitary, medulla oblongata, and kidney, while medium levels were noted in the thalamus, pons, olfactory bulb, and heart. Immunohistochemistry identified gp-ghrelin-immunopositive cells in the gastric mucosa and pancreas. Intraperitoneal injection of gp-ghrelin increased food intake in the guinea pig. Gp-ghrelin did not cause any mechanical responses in isolated gastrointestinal smooth muscles in vitro, similar to rat ghrelin. In conclusion, the N-terminal structures that are conserved in mammals were different in gp-ghrelin. Moreover, the functional characteristics of gp-ghrelin, other than its distribution, were dissimilar from those in other Rodentia.
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Affiliation(s)
- Yuji Okuhara
- School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan; Pathology Research, Safety Research Laboratory, Kissei Pharmaceutical Co., Ltd., 2320-1, Maki, Hotaka, Azumino, Nagano 399-8305, 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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15
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Romański KW. Importance of the enteric nervous system in the control of the migrating motility complex. Physiol Int 2017; 104:97-129. [PMID: 28665193 DOI: 10.1556/2060.104.2017.2.4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The migrating motility complex (MMC), a cyclical phenomenon, represents rudimentary motility pattern in the gastrointestinal tract. The MMC is observed mostly in the stomach and gut of man and numerous animal species. It contains three or four phases, while its phase III is the most characteristic. The mechanisms controlling the pattern are unclear in part, although the neural control of the MMC seems crucial. The main goal of this article was to discuss the importance of intrinsic innervation of the gastrointestinal tract in MMC initiation, migration, and cessation to emphasize that various MMC-controlling mechanisms act through the enteric nervous system. Two main neural regions, central and peripheral, are able to initiate the MMC. However, central regulation of the MMC may require cooperation with the enteric nervous system. When central mechanisms are not active, the MMC can be initiated peripherally in any region of the small bowel. The enteric nervous system affects the MMC in response to the luminal stimuli which can contribute to the initiation and cessation of the cycle, and it may evoke irregular phasic contractions within the pattern. The hormonal regulators released from the endocrine cells may exert a modulatory effect upon the MMC mostly through the enteric nervous system. Their central action could also be considered. It can be concluded that the enteric nervous system is involved in the great majority of the MMC-controlling mechanisms.
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Affiliation(s)
- K W Romański
- 1 Department of Animal Physiology, Faculty of Veterinary Medicine, Wrocław University of Environmental and Life Sciences , Wrocław, Poland
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16
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Luo D, Qu C, Lin G, Zhang Z, Xie J, Chen H, Liang J, Li C, Wang H, Su Z. Character and laxative activity of polysaccharides isolated from Dendrobium officinale. J Funct Foods 2017. [DOI: 10.1016/j.jff.2017.04.024] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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Mosińska P, Zatorski H, Storr M, Fichna J. Future Treatment of Constipation-associated Disorders: Role of Relamorelin and Other Ghrelin Receptor Agonists. J Neurogastroenterol Motil 2017; 23:171-179. [PMID: 28238253 PMCID: PMC5383112 DOI: 10.5056/jnm16183] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 12/19/2016] [Accepted: 01/08/2017] [Indexed: 12/22/2022] Open
Abstract
There is an unmet need for effective pharmacological therapies for constipation, a symptom that significantly deteriorates patients’ quality of life and impacts health care. Ghrelin is an endogenous ligand for the growth hormone secretagogue receptor and has been shown to exert prokinetic effects on gastrointestinal (GI) motility via the vagus and pelvic nerves. The pharmacological potential of ghrelin is hampered by its short half-life. Ghrelin receptor (GRLN-R) agonists with enhanced pharmacokinetics were thus developed. Centrally penetrant GRLN-R agonists stimulate defecation and improve impaired lower GI transit in animals and humans. This review summarizes the current knowledge on relamorelin, a potent ghrelin mimetic, and other GRLN-R analogs which are in preclinical or clinical stages of development for the management of disorders with underlying GI hypomotility, like constipation.
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Affiliation(s)
- Paula Mosińska
- Department of Biochemistry, Faculty of Medicine, Medical University of Lodz, Lodz, Poland
| | - Hubert Zatorski
- Department of Biochemistry, Faculty of Medicine, Medical University of Lodz, Lodz, Poland
| | - Martin Storr
- Center of Endoscopy, Starnberg, Germany and Walter-Brendel-Centre, Ludwig-Maximilians University Munich, Munich, Germany
| | - Jakub Fichna
- Department of Biochemistry, Faculty of Medicine, Medical University of Lodz, Lodz, Poland
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18
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Grabauskas G, Owyang C. Plasticity of vagal afferent signaling in the gut. MEDICINA-LITHUANIA 2017; 53:73-84. [PMID: 28454890 PMCID: PMC6318799 DOI: 10.1016/j.medici.2017.03.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 03/21/2017] [Indexed: 12/13/2022]
Abstract
Vagal sensory neurons mediate the vago-vagal reflex which, in turn, regulates a wide array of gastrointestinal functions including esophageal motility, gastric accommodation and pancreatic enzyme secretion. These neurons also transmit sensory information from the gut to the central nervous system, which then mediates the sensations of nausea, fullness and satiety. Recent research indicates that vagal afferent neurons process non-uniform properties and a significant degree of plasticity. These properties are important to ensure that vagally regulated gastrointestinal functions respond rapidly and appropriately to various intrinsic and extrinsic factors. Similar plastic changes in the vagus also occur in pathophysiological conditions, such as obesity and diabetes, resulting in abnormal gastrointestinal functions. A clear understanding of the mechanisms which mediate these events may provide novel therapeutic targets for the treatment of gastrointestinal disorders due to vago-vagal pathway malfunctions.
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Affiliation(s)
- Gintautas Grabauskas
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48019, USA.
| | - Chung Owyang
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48019, USA
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19
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Cowan E, Burch KJ, Green BD, Grieve DJ. Obestatin as a key regulator of metabolism and cardiovascular function with emerging therapeutic potential for diabetes. Br J Pharmacol 2016; 173:2165-81. [PMID: 27111465 DOI: 10.1111/bph.13502] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 04/05/2016] [Accepted: 04/15/2016] [Indexed: 01/01/2023] Open
Abstract
Obestatin is a 23-amino acid C-terminally amidated gastrointestinal peptide derived from preproghrelin and which forms an α helix. Although obestatin has a short biological half-life and is rapidly degraded, it is proposed to exert wide-ranging pathophysiological actions. Whilst the precise nature of many of its effects is unclear, accumulating evidence supports positive actions on both metabolism and cardiovascular function. For example, obestatin has been reported to inhibit food and water intake, body weight gain and gastrointestinal motility and also to mediate promotion of cell survival and prevention of apoptosis. Obestatin-induced increases in beta cell mass, enhanced adipogenesis and improved lipid metabolism have been noted along with up-regulation of genes associated with beta cell regeneration, insulin production and adipogenesis. Furthermore, human circulating obestatin levels generally demonstrate an inverse association with obesity and diabetes, whilst the peptide has been shown to confer protective metabolic effects in experimental diabetes, suggesting that it may hold therapeutic potential in this setting. Obestatin also appears to be involved in blood pressure regulation and to exert beneficial effects on endothelial function, with experimental studies indicating that it may also promote cardioprotective actions against, for example, ischaemia-reperfusion injury. This review will present a critical appraisal of the expanding obestatin research area and discuss the emerging therapeutic potential of this peptide for both metabolic and cardiovascular complications of diabetes.
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Affiliation(s)
- Elaine Cowan
- Queen's University Belfast, Institute for Global Food Security, School of Biological Sciences, Belfast, UK
| | - Kerry J Burch
- Queen's University Belfast, Wellcome-Wolfson Institute for Experimental Medicine, Belfast, UK
| | - Brian D Green
- Queen's University Belfast, Institute for Global Food Security, School of Biological Sciences, Belfast, UK
| | - David J Grieve
- Queen's University Belfast, Wellcome-Wolfson Institute for Experimental Medicine, Belfast, UK
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Abstract
There remains an unmet need for effective pharmacologic treatments for gastroparesis. Ghrelin is the endogenous ligand for the growth hormone secretagogue receptor and has been shown to regulate energy homeostasis and exert prokinetic effects on gastrointestinal motility. In recent years, several ghrelin receptor agonists have been studied in clinical trials of patients with diabetic gastroparesis. The intravenous macrocyclic peptidomimetic, TZP-101, initially suggested improvement in gastroparesis symptoms with intravenous administration when compared to placebo. However, in subsequent studies of oral preparations, TZP-102 failed to confirm these results. Another ghrelin receptor agonist, RM-131, was recently shown to significantly accelerate gastric emptying (GE) in patients with type 1 and type 2 diabetes and delayed GE. RM-131 reduced total Gastroparesis Cardinal Symptom Index-Daily Diary (GCSI-DD) and composite scores among type 1 diabetics. Continued development of ghrelin agonists should be explored in attempts to expand therapeutic options for the treatment of gastroparesis.
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21
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Zhao J, Gao B, Zhang Y, Zheng B, Liu H, Cao JL. Effects of intrathecal opioids combined with low-dose naloxone on motilin and its receptor in a rat model of postoperative pain. Life Sci 2014; 103:88-94. [DOI: 10.1016/j.lfs.2014.03.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 03/12/2014] [Accepted: 03/31/2014] [Indexed: 12/28/2022]
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22
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Wang W, Cheng L, Guo J, Ma Y, Li F. Expression of Ghrelin in gastrointestinal tract and the effect of early weaning on Ghrelin expression in lambs. Mol Biol Rep 2014; 41:909-14. [DOI: 10.1007/s11033-013-2935-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 12/20/2013] [Indexed: 10/25/2022]
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23
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Ariyasu H, Iwakura H, Yukawa N, Murayama T, Yokode M, Tada H, Yoshimura K, Teramukai S, Ito T, Shimizu A, Yonezawa A, Kangawa K, Mimori T, Akamizu T. Clinical effects of ghrelin on gastrointestinal involvement in patients with systemic sclerosis. Endocr J 2014; 61:735-42. [PMID: 24739333 DOI: 10.1507/endocrj.ej14-0088] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The majority of patients with systemic sclerosis (SSc) have gastrointestinal (GI) tract involvement, but therapies using prokinetic agents are usually unsatisfactory. Ghrelin stimulates gastric motility in healthy human volunteers. In this study, we investigated whether ghrelin could improve gastric emptying in patients with gastrointestinal symptoms due to SSc. The study was performed in a randomized, double-blind, placebo-controlled crossover fashion on two occasions. Ten SSc patients with GI tract involvement received an infusion of either ghrelin (5.0 μg/kg) or saline, and gastric emptying rate was evaluated by ¹³C-acetic acid breath test. Gastric emptying was significantly accelerated by ghrelin infusion in patients with SSc (ghrelin vs. saline: 43.3 ± 11.4 min vs. 53.4 ± 5.4 min, P=0.03). No serious adverse effects were observed. Our results suggest that ghrelin might represent a new therapeutic approach for GI tract involvement in patients with SSc.
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Affiliation(s)
- Hiroyuki Ariyasu
- Ghrelin Research Project, Translational Research Center, Kyoto University Hospital, Kyoto 606-8507, Japan
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Bashashati M, McCallum RW. Neurochemical mechanisms and pharmacologic strategies in managing nausea and vomiting related to cyclic vomiting syndrome and other gastrointestinal disorders. Eur J Pharmacol 2013; 722:79-94. [PMID: 24161560 DOI: 10.1016/j.ejphar.2013.09.075] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2013] [Revised: 09/24/2013] [Accepted: 09/27/2013] [Indexed: 12/18/2022]
Abstract
Nausea and vomiting are common gastrointestinal complaints which could be triggered by stimuli in both the peripheral and central nervous systems. They may be considered as defense mechanisms when threatening toxins/agents enter the gastrointestinal tract or there is excessive retention of gastrointestinal contents due to obstruction. The pathophysiology of nausea and vomiting is complex and much still remains unknown. Therefore, treatments are restricted or ineffective in many cases. Nausea and vomiting with functional etiologies including cyclic vomiting syndrome are challenging in gastroenterology. In this article, we review potential pathways, neurochemical transmitters, and their receptors which are possibly involved in the pathophysiology of nausea and vomiting including the entity cyclic vomiting syndrome.
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Affiliation(s)
- Mohammad Bashashati
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
| | - Richard W McCallum
- Department of Internal Medicine, Texas Tech University Health Sciences Center, El Paso, TX, USA.
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25
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Avau B, Carbone F, Tack J, Depoortere I. Ghrelin signaling in the gut, its physiological properties, and therapeutic potential. Neurogastroenterol Motil 2013; 25:720-32. [PMID: 23910374 DOI: 10.1111/nmo.12193] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 06/26/2013] [Indexed: 02/08/2023]
Abstract
BACKGROUND Ghrelin, an orexigenic hormone secreted from the stomach, was soon after its discovery hypothesized to be a prokinetic agent, due to its homology to motilin. Studies in animals and humans, using ghrelin and ghrelin receptor agonists, confirmed this hypothesis, suggesting a therapeutic potential for the ghrelin receptor in the treatment of gastrointestinal motility disorders. Precilinical studies demonstrated that ghrelin can act directly on ghrelin receptors on the enteric nervous system, but the predominant route of action under physiological circumstances is signaling via the vagus nerve in the upper gastrointestinal tract and the pelvic nerves in the colon. Different pharmaceutical companies have designed stable ghrelin mimetics that revealed promising results in trials for the treatment of diabetic gastroparesis and post-operative ileus. Nevertheless, no drug was able to reach the market so far, facing problems proving superiority over placebo treatment in larger trials. PURPOSE This review aims to summarize the road that led to the current knowledge concerning the prokinetic properties of ghrelin with a focus on the therapeutic potential of ghrelin receptor agonists in the treatment of hypomotility disorders. In addition, we outline some of the problems that could be at the basis of the negative outcome of the trials with ghrelin agonists and question whether the right target groups were selected. It is clear that a new approach is needed to develop marketable drugs with this class of gastroprokinetic agents.
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Affiliation(s)
- B Avau
- Translational Research Center for Gastrointestinal Disorders, University of Leuven, Leuven, Belgium
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26
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Abstract
Ingestion of food affects the secretion of hormones from specialized endocrine cells scattered within the intestinal mucosa. Upon release, these hormones mostly decrease food intake by signaling information to the brain. Although enteroendocrine cells in the small intestine were thought to represent the predominant gut-brain regulators of food intake, recent advances also established a major role for gastric hormones in these regulatory pathways. First and foremost, the gastric endocrine X/A-like cell was in the focus of many studies due to the production of ghrelin, which is until now the only known orexigenic hormone that is peripherally produced and centrally acting. Although X/A-cells were initially thought to only release one hormone that stimulates food intake, this view has changed with the identification of additional peptide products also derived from this cell, namely desacyl ghrelin, obestatin, and nesfatin-1. Desacyl ghrelin may play a counter-regulatory role to the food intake stimulatory effect of ghrelin. The same property was suggested for obestatin; however, this hypothesis could not be confirmed in numerous subsequent studies. Moreover, the description of the stomach as the major source of the novel anorexigenic hormone nesfatin-1 derived from the NUCB2 gene further corroborated the assumption that the gastric X/A-like cell products are not only stimulant but also inhibitors of feeding, thereby acting as so far unique dual regulator of food intake located in a logistically important place where the gastrointestinal tract has initial contact with food.
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Affiliation(s)
- Andreas Stengel
- Charité Center for Internal Medicine and Dermatology, Division Psychosomatic Medicine, Obesity Center Berlin, Charité Universitätsmedizin Berlin, Campus Mitte, Charitéplatz 1, 10117 Berlin, Germany.
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Greenwood-Van Meerveld B, Tyler K, Mohammadi E, Pietra C. Efficacy of ipamorelin, a ghrelin mimetic, on gastric dysmotility in a rodent model of postoperative ileus. J Exp Pharmacol 2012; 4:149-55. [PMID: 27186127 PMCID: PMC4863553 DOI: 10.2147/jep.s35396] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Background Delayed gastric emptying is a common disorder with few effective therapeutic options. The goal of this study was to investigate whether ipamorelin, a synthetic peptidomimetic that acts on the ghrelin receptor, accelerates gastric emptying in a rodent model of gastroparesis induced by abdominal surgery and intestinal manipulation. Methods Fasted adult male rats were subjected to laparotomy and intestinal manipulation. Following the surgery rats received ipamorelin (0.014–0.14 µmol/kg) or vehicle control via intravenous administration. Gastric emptying was measured by the percent of total recovered radioactivity remaining in the stomach 15 minutes after intragastric gavage of 1.5 mL of 99mTc (technicium-99m) sulfur colloid in 0.5% methylcellulose. In a separate group of rats subjected to laparotomy and intestinal manipulation, the gastric fundus was isolated and tissue segments were suspended in an organ bath to assess the effect of ipamorelin (1 µM) on gastric smooth muscle contractility induced by acetylcholine and electrical field stimulation. Results Abdominal surgery caused a delay in gastric emptying with 78% ± 5% of the meal remaining in the stomach in vehicle controls. Ipamorelin (0.014 µmol/kg intravenous) resulted in a significant acceleration (P < 0.05 vs vehicle-treated rat) of gastric emptying with 52% ± 11% of the meal remaining in the stomach compared to nonsurgical control animals with 44% ± 6%. Following abdominal surgery and intestinal manipulation, isolated preparations of gastric smooth muscle exhibited a marked inhibition of acetylcholine and electrical field stimulation-induced contractile responses, which were reversed by ipamorelin and ghrelin. Conclusion These results suggest that ipamorelin accelerates gastric emptying in a rodent model of postoperative ileus through the stimulation of gastric contractility by activating a ghrelin receptor-mediated mechanism involving cholinergic excitatory neurons.
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Affiliation(s)
- Beverley Greenwood-Van Meerveld
- VA Medical Center, University of Oklahoma Health Science Center, Oklahoma City, OK, USA; Department of Physiology, University of Oklahoma Health Science Center, Oklahoma City, OK, USA; Oklahoma Center for Neuroscience, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Karl Tyler
- Oklahoma Center for Neuroscience, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Ehsan Mohammadi
- Oklahoma Center for Neuroscience, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
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Verhulst PJ, Depoortere I. Ghrelin's second life: From appetite stimulator to glucose regulator. World J Gastroenterol 2012; 18:3183-95. [PMID: 22783041 PMCID: PMC3391754 DOI: 10.3748/wjg.v18.i25.3183] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 12/01/2011] [Accepted: 01/18/2012] [Indexed: 02/06/2023] Open
Abstract
Ghrelin, a 28 amino acid peptide hormone produced by the stomach, was the first orexigenic hormone to be discovered from the periphery. The octanoyl modification at Ser3, mediated by ghrelin O-acyltransferase (GOAT), is essential for ghrelin’s biological activity. Ghrelin stimulates food intake through binding to its receptor (GRLN-R) on neurons in the arcuate nucleus of the hypothalamus. Ghrelin is widely expressed throughout the body; accordingly, it is implicated in several other physiological functions, which include growth hormone release, gastric emptying, and body weight regulation. Ghrelin and GRLN-R expression are also found in the pancreas, suggesting a local physiological role. Accordingly, several recent studies now point towards an important role for ghrelin and its receptor in the regulation of blood glucose homeostasis, which is the main focus of this review. Several mechanisms of this regulation by ghrelin have been proposed, and one possibility is through the regulation of insulin secretion. Despite some controversy, most studies suggest that ghrelin exerts an inhibitory effect on insulin secretion, resulting in increased circulating glucose levels. Ghrelin may thus be a diabetogenic factor. Obesity-related type 2 diabetes has become an increasingly important health problem, almost reaching epidemic proportions in the world; therefore, antagonists of the ghrelin-GOAT signaling pathway, which will tackle both energy- and glucose homeostasis, may be considered as promising new therapies for this disease.
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Nunoi H, Matsuura B, Utsunomiya S, Ueda T, Miyake T, Furukawa S, Kumagi T, Ikeda Y, Abe M, Hiasa Y, Onji M. A relationship between motilin and growth hormone secretagogue receptors. ACTA ACUST UNITED AC 2012; 176:28-35. [DOI: 10.1016/j.regpep.2012.03.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Revised: 02/27/2012] [Accepted: 03/20/2012] [Indexed: 12/19/2022]
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Stengel A, Taché Y. Yin and Yang - the Gastric X/A-like Cell as Possible Dual Regulator of Food Intake. J Neurogastroenterol Motil 2012; 18:138-49. [PMID: 22523723 PMCID: PMC3325299 DOI: 10.5056/jnm.2012.18.2.138] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Accepted: 03/11/2012] [Indexed: 01/14/2023] Open
Abstract
Ingestion of food affects secretion of hormones from enteroendocrine cells located in the gastrointestinal mucosa. These hormones are involved in the regulation of various gastrointestinal functions including the control of food intake. One cell in the stomach, the X/A-like has received much attention over the past years due to the production of ghrelin. Until now, ghrelin is the only known orexigenic hormone that is peripherally produced and centrally acting to stimulate food intake. Subsequently, additional peptide products of this cell have been described including desacyl ghrelin, obestatin and nesfatin-1. Desacyl ghrelin seems to be involved in the regulation of food intake as well and could play a counter-balancing role of ghrelin's orexigenic effect. In contrast, the initially proposed anorexigenic action of obestatin did not hold true and therefore the involvement of this peptide in the regulation of feeding is questionable. Lastly, the identification of nesfatin-1 in the same cell in different vesicles than ghrelin extended the function of this cell type to the inhibition of feeding. Therefore, this X/A-like cell could play a unique role by encompassing yin and yang properties to mediate not only hunger but also satiety.
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Affiliation(s)
- Andreas Stengel
- Department of Medicine, Division Psychosomatic Medicine and Psychotherapy, Charité, Campus Mitte, Universitätsmedizin Berlin, Berlin, Germany
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31
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Iwasaki E, Suzuki H, Masaoka T, Nishizawa T, Hosoda H, Kangawa K, Hibi T. Enhanced gastric ghrelin production and secretion in rats with gastric outlet obstruction. Dig Dis Sci 2012; 57:858-64. [PMID: 22052447 DOI: 10.1007/s10620-011-1953-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Accepted: 10/12/2011] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND AIM Ghrelin has distinct effects on gastrointestinal motility through the vagus nerve and gastric excitatory neural plexus. The objectives of this study were to investigate the dynamics of ghrelin and expression of neuromuscular markers in a newly established surgically manipulated rat model of gastric outlet obstruction (GOO), akin to the pyloric stricture associated with duodenal ulcer, advanced gastric cancer, and other conditions, in the clinical setting. MATERIAL AND METHODS The rats were divided into two groups, a control group (sham operation) and the GOO group (proximal duodenal stricture). The animals were sacrificed 2 weeks after the operation. Plasma and gastric ghrelin were measured by radioimmunoassay. mRNA expression in the stomach of neural choline acetyltransferase (ChAT), c-kit, and membrane-bound stem cell factor (SCF) were analyzed by quantitative RT-PCR. In addition, gastric mRNA expression of the aforementioned were also evaluated 60 min after intraperitoneal administration of a synthetic GHS-R1a antagonist ([D: -Lys3] GHRP-6 6.0 mg/kg). RESULTS Mechanical GOO induced increases of fasting plasma ghrelin levels and hyperplasia of the gastric muscle layers, with enhanced expression of the gastric neuromuscular markers. Administration of [D: -Lys3] GHRP-6 normalized the enhanced expression of c-kit and SCF. CONCLUSION GOO stimulates ghrelin dynamics and then enhances the mechanistic expression of gastric cellular communication network molecules between nerves and smooth muscle cells.
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Affiliation(s)
- Eisuke Iwasaki
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
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Abstract
The migrating motor complex (MMC) is a cyclic, recurring motility pattern that occurs in the stomach and small bowel during fasting; it is interrupted by feeding. The MMC is present in the gastrointestinal tract of many species, including humans. The complex can be subdivided into four phases, of which phase III is the most active, with a burst of contractions originating from the antrum or duodenum and migrating distally. Control of the MMC is complex. Phase III of the MMC with an antral origin can be induced in humans through intravenous administration of motilin, erythromycin or ghrelin, whereas administration of serotonin or somatostatin induces phase III activity with duodenal origin. The role of the vagus nerve in control of the MMC seems to be restricted to the stomach, as vagotomy abolishes the motor activity in the stomach, but leaves the periodic activity in the small bowel intact. The physiological role of the MMC is incompletely understood, but its absence has been associated with gastroparesis, intestinal pseudo-obstruction and small intestinal bacterial overgrowth. Measuring the motility of the gastrointestinal tract can be important for the diagnosis of gastrointestinal disorders. In this Review we summarize current knowledge of the MMC, especially its role in health and disease.
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Xu X, Zhu Y, Chuai J. Changes in serum ghrelin and small intestinal motility in rats with ischemic stroke. Anat Rec (Hoboken) 2011; 295:307-12. [PMID: 22190447 DOI: 10.1002/ar.21490] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2011] [Accepted: 08/26/2011] [Indexed: 11/05/2022]
Abstract
Ischemic stroke occurs as a result of an obstruction within a blood vessel supplying blood to the brain. Gastrointestinal mucosal damage not only induces local and systemic inflammatory reactions but may also result in multiple organ dysfunction syndrome. We studied whether the changes in serum ghrelin and small intestinal motility occur in cerebral ischemia. The focal cerebral ischemia rat models were produced by the middle cerebral artery occlusion (MCAO) method. The MCAO group was further equally divided into five subgroups at 3, 6, 12, 24, and 48 hr, and the sham operated rats were used as controls. Serum ghrelin level was analyzed using enzyme-linked immunosorbent assay, and small intestinal motility was measured by methylene blue staining. The ileum tissue was examined by light and electron microscopy. The neurologic scores were 0 for all the rats in the control group and 2-3 for those in the MCAO group, suggesting that rat models were established successfully. The serum ghrelin level was higher in the MCAO group when compared with the control group (P < 0.05). However, the impelling force in MCAO rats was significantly lower than that of the control group (P < 0.05), reaching the lowest level at 24 hr. Damage to the intestinal mucosa, including villus intestinalis, vacuolar degeneration of organelles, widened cell-cell junctions, and apoptotic cells could be found under the light and electron microscopy. Our results showed that higher level of serum ghrelin decreased gastrointestinal motility and damage to the intestinal mucosa existed in rats with MCAO.
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Affiliation(s)
- Xinping Xu
- Department of Gastroenterology, Beijing Tiantan Hospital, Capital Medical University, Beijing 100050, China
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Greenwood-Van Meerveld B, Kriegsman M, Nelson R. Ghrelin as a target for gastrointestinal motility disorders. Peptides 2011; 32:2352-6. [PMID: 21453735 DOI: 10.1016/j.peptides.2011.03.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 03/15/2011] [Accepted: 03/17/2011] [Indexed: 12/26/2022]
Abstract
The therapeutic potential of ghrelin and synthetic ghrelin receptor (GRLN-R) agonists for the treatment of gastrointestinal (GI) motility disorders is based on their ability to stimulate coordinated patterns of propulsive GI motility. This review focuses on the latest findings that support the therapeutic potential of GRLN-R agonists for the treatment of GI motility disorders. The review highlights the preclinical and clinical prokinetic effects of ghrelin and a series of novel ghrelin mimetics to exert prokinetic effects on the GI tract. We build upon a series of excellent reviews to critically discuss the evidence that supports the potential of GRLN-R agonists to normalize GI motility in patients with GI hypomotility disorders such as gastroparesis, post-operative ileus (POI), idiopathic chronic constipation and functional bowel disorders.
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35
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Gallas S, Fetissov SO. Ghrelin, appetite and gastric electrical stimulation. Peptides 2011; 32:2283-9. [PMID: 21672567 DOI: 10.1016/j.peptides.2011.05.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 05/26/2011] [Accepted: 05/27/2011] [Indexed: 12/18/2022]
Abstract
Ghrelin is a peptide hormone produced mainly by the stomach and has widespread physiological functions including increase in appetite. The stimulation of the ghrelin system represents a potential therapeutic approach in various disorders characterized by deficient ghrelin signaling or by low appetite. This stimulation may be achieved via pharmacological targeting of the ghrelin receptor with synthetic ghrelin or ghrelin mimetics or via increased endogenous ghrelin production. Recently, it was demonstrated that gastric electrical stimulation (GES) with Enterra parameters results in increased ghrelin production in rats. Furthermore, recent data revealed putative role of ghrelin-reactive immunoglobulins in the modulation of the ghrelin signaling which can be also stimulated by GES. Here, we review the links between GES and ghrelin in existing GES experimental and clinical applications for treatment of gastroparesis, functional dyspepsia or obesity and discuss if GES can be proposed as a non-pharmacological approach to improve ghrelin secretion in several pathological conditions characterized by low appetite, such as anorexia nervosa or anorexia-cachexia syndrome.
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Affiliation(s)
- Syrine Gallas
- Digestive System & Nutrition Laboratory, ADEN EA4311, Rouen University, IFR23, Rouen 76183, France
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36
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Guo F, Xu L, Sun X, Gao S, Zhu H. The paraventricular nucleus modulates thyroidal motilin release and rat gastric motility. J Neuroendocrinol 2011; 23:767-77. [PMID: 21756270 DOI: 10.1111/j.1365-2826.2011.02190.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Motilin, an important endocrine regulator of gastrointestinal motility, was once considered to be produced in the gastrointestinal tract and brain. In recent years, however, motilin has been found in the human thyroid, as well as in that of the guinea pig. The physiological function and central modulation of thyroidal motilin remain poorly understood. To determine the functional role of thyroidal motilin, we observed the concentration of motilin in the plasma and also gastric motility before and after thyroidectomy. Our studies show that both the concentration of plasma motilin and gastric motility were decreased after thyroidectomy. To explore modulation-related nuclei, a c-Fos immune response experiment was carried out. The PVN of the hypothalamus was the main area of reactivity after thyroidectomy. Subsequently, we studied the effects of electrical excitation and PVN lesions on gastric motility and the expression of motilin in the thyroid and plasma. Excitation of the PVN was shown to prompt gastric motility that was partly prevented by the motilin receptor antagonist, GM-109. The effects of PVN excitation on gastric contraction were significantly reduced in thyroidectomised rats. In addition, the expression of motilin in the thyroid was significantly increased after PVN excitation and decreased after PVN lesions. The changes in the concentration of motilin in plasma induced by PVN stimulation were positively correlated with changes of gastric motility. In our in vitro study, the motilin secreted from TT cells (a parafollicular cell line originating from human thyroid medullary carcinoma) gradually increased on day 6 of culture, and motilin and calcitonin (CT) were co-expressed in TT cells. These results demonstrate that motilin from the thyroid could be secreted into the peripheral plasma and affect gastric motility and that PVN was a central nucleus for modulating gastric motility and motilin expression in the thyroid.
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Affiliation(s)
- F Guo
- Department of Pathophysiology, Medical College of Qingdao University, Qingdao, Shandong, China
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37
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Kitazawa T, Nakamura T, Saeki A, Teraoka H, Hiraga T, Kaiya H. Molecular identification of ghrelin receptor (GHS-R1a) and its functional role in the gastrointestinal tract of the guinea-pig. Peptides 2011; 32:1876-86. [PMID: 21843569 DOI: 10.1016/j.peptides.2011.07.026] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Revised: 07/28/2011] [Accepted: 07/29/2011] [Indexed: 11/20/2022]
Abstract
Ghrelin stimulates gastric motility in vivo in the guinea-pig through activation of growth hormone secretagogue receptor (GHS-R). In this study, we identified GHS-R1a in the guinea-pig, and examined its distribution and cellular function and compared them with those in the rat. Effects of ghrelin in different regions of gastrointestinal tract were also examined. GHS-R1a was identified in guinea-pig brain cDNA. Amino acid identities of guinea-pig GHS-R1a were 93% to horses and 85% to dogs. Expression levels of GHS-R1a mRNA were high in the pituitary and hypothalamus, moderate in the thalamus, cerebral cortex, pons, medulla oblongata and olfactory bulb, and low in the cerebellum and peripheral tissues including gastrointestinal tract. Comparison of GHS-R1a expression patterns showed that those in the brain were similar but the expression level in the gastrointestinal tract was higher in rats than in guinea-pigs. Guinea-pig GHS-R1a expressed in HEK 293 cells responded to rat ghrelin and GHS-R agonists. Rat ghrelin was ineffective in inducing mechanical changes in the stomach and colon but caused a slight contraction in the small intestine. 1,1-Dimethyl-4-phenylpiperazinium and electrical field stimulation (EFS) caused cholinergic contraction in the intestine, and these contractions were not affected by ghrelin. Ghrelin did not change spontaneous and EFS-evoked [(3)H]-efflux from [(3)H]-choline-loaded ileal strips. In summary, guinea-pig GHS-R1a was identified and its functions in isolated gastrointestinal strips were characterized. The distribution of GHS-R1a in peripheral tissues was different from that in rats, suggesting that the functional role of ghrelin in the guinea-pig is different from that in other animal species.
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Affiliation(s)
- Takio Kitazawa
- Department of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan.
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Sanger GJ, Holbrook JD, Andrews PLR. The translational value of rodent gastrointestinal functions: a cautionary tale. Trends Pharmacol Sci 2011; 32:402-9. [PMID: 21531468 DOI: 10.1016/j.tips.2011.03.009] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Revised: 03/18/2011] [Accepted: 03/22/2011] [Indexed: 02/06/2023]
Abstract
Understanding relationships between gene complements and physiology is important, especially where major species-dependent differences are apparent. Molecular and functional differences between rodents (rats, mice, guinea pigs) and humans are increasingly reported. Recently, the motilin gene, which encodes a gastrointestinal hormone widely detected in mammals, was found to be absent in rodents where the receptors are pseudogenes; however, actions of motilin in rodents are sometimes observed. Although ghrelin shares common ancestry with motilin, major species-dependent abberations are not reported. The apparently specific absence of functional motilin in rodents is associated with specialised digestive physiology, including loss of ability to vomit; motilin is functional in mammals capable of vomiting. The exception is rabbit, the only other mammal unable to vomit, in which motilin might be conserved to regulate caecotrophy, another specialised digestive process. Motilin illustrates a need for caution when translating animal functions to humans. Nevertheless, motilin receptor agonists are under development as gastroprokinetic drugs.
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Affiliation(s)
- Gareth J Sanger
- Wingate Institute of Neurogastroenterology, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, 26 Ashfield Street, London, E1 2AJ, UK.
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Xu L, Gao S, Guo F, Sun X. Effect of motilin on gastric distension sensitive neurons in arcuate nucleus and gastric motility in rat. Neurogastroenterol Motil 2011; 23:265-70, e120-1. [PMID: 21303429 DOI: 10.1111/j.1365-2982.2010.01661.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND Intestinal motilin is known to stimulate gastrointestinal (GI) motility and the arcuate nucleus (Arc) of hypothalamus is shown to be involved in the regulation of GI motility. METHODS Single unit discharges in the Arc were recorded extracellularly by implantation of a force transducer into the stomach in rats, to evaluate the effect of motilin on gastric motility. Projection of nerve fiber and expression of motilin were observed by retrograde tracer deposits of Fluoro-Gold (FG) and fluo-immunohistochemistry staining. KEY RESULTS 65.5% of neurons in Arc responded to gastric distension (GD), 55.6% of which showed excitation (GD-E), and 44.4% showed inhibition (GD-I). After GD, the firing rate of GD-E neurons significantly increased (P<0.01), but decreased for GD-I neurons (P<0.01). Most of both GD-E and GD-I neurons were activated by motilin (P<0.05). The frequency and amplitude of gastric contractions significantly increased by administration of motilin in Arc with a dose dependent manner (P<0.05-0.01). However, pretreatment with GM109 could abolish the responses of neurons and excitatory effect of gastric motility induced by motilin. Motilin immunoreactive neurons were increased in Arc via gastric distention (P<0.05). Motilin/FG-labeled neurons were detected in hypothalamus paraventricular nucleus (PVN). CONCLUSIONS & INFERENCES Our findings suggest that motilin neurons in Arc may accept peripheral somatosensory afferent inputs from gastric mechanoreceptors of the stomach, and also may acts as a stimulatory factor in Arc to regulate gastric motility via some inferior nucleus relay pathway. The results provide insight into the role of Arc in the control of digestion mediated via motilin.
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Affiliation(s)
- L Xu
- Department of Pathophysiology, Medical College of Qingdao University, Qingdao, Shandong, China.
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Unger MM, Möller JC, Mankel K, Eggert KM, Bohne K, Bodden M, Stiasny-Kolster K, Kann PH, Mayer G, Tebbe JJ, Oertel WH. Postprandial ghrelin response is reduced in patients with Parkinson's disease and idiopathic REM sleep behaviour disorder: a peripheral biomarker for early Parkinson's disease? J Neurol 2010; 258:982-90. [PMID: 21181542 DOI: 10.1007/s00415-010-5864-1] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Revised: 11/30/2010] [Accepted: 12/01/2010] [Indexed: 12/13/2022]
Abstract
Ghrelin, an orexigenic peptide, has multiple functions, which include promoting gastrointestinal motility and influencing higher brain functions. Experimental data suggest that ghrelin has neuroprotective potential in the MPTP mouse model of Parkinson's disease (PD). PD patients show delayed gastric emptying and other symptoms that may relate to disturbed excretion of ghrelin. No data are available on postprandial ghrelin response in patients with PD and idiopathic REM sleep behaviour disorder (iRBD)--a condition considered a putative preclinical stage of PD. We measured fasting and postprandial ghrelin serum concentrations in 20 healthy controls, 39 (including 19 drug-naïve) PD patients and 11 iRBD patients using a commercial radioimmunoassay for total ghrelin. For statistical analysis we employed ANCOVA and post-hoc testing with Bonferroni's method. Controls showed a decrease of mean fasting ghrelin serum concentrations in the early postprandial phase, followed by a recuperation starting 60 min after the test meal and reaching a maximum at 300 min. This recuperation was less pronounced in PD and iRBD; the slope of relative postprandial ghrelin recovery was different between the investigated groups (p = 0.007). Post-hoc testing showed a difference between controls and PD patients (p = 0.002) and between controls and iRBD patients (p = 0.037). The dynamic regulation of ghrelin in response to food intake is partially impaired in subjects at putative preclinical (iRBD) and clinical stages of PD. Reduced ghrelin excretion might increase the vulnerability of nigrostriatal dopaminergic neurons as suggested by animal studies. The impaired ghrelin excretion might qualify as a peripheral biomarker and be of diagnostic or therapeutic value.
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Affiliation(s)
- Marcus M Unger
- Department of Neurology, Philipps-Universität Marburg, Rudolf-Bultmann-Strasse 8, 35033, Marburg, Germany.
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Liu H, Qiu D, Zhou X, Niu W, Qin X, Cai Y, Wang J, Chen Y. Erythromycin inhibited glycinergic inputs to gastric vagal motoneurons in brainstem slices of newborn rats. Neurogastroenterol Motil 2010; 22:1232-9. [PMID: 20731779 DOI: 10.1111/j.1365-2982.2010.01586.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND Motilin has been known to stimulate the motility of digestive organs peripherally via activation of motilin receptors located at gastrointestinal (GI) cholinergic nerve endings and/or smooth muscle cells. Recent studies have indicated that motilin may also promote GI motility via actions in the central nervous system; however the sites of action and the mechanisms are not clear yet. The present study aimed to test the hypothesis that motilin receptor agonist erythromycin alters the synaptic inputs of preganglionic gastric vagal motoneurons (GVMs) located in the dorsal motor nucleus of the vagus (DMV). METHODS Gastric vagal motoneurons were retrogradely labeled by fluorescent tracer from the stomach wall of newborn rats. Fluorescently labeled GVMs in DMV were recorded using whole-cell patch-clamp in brainstem slices and the effects of motilin receptor agonist erythromycin on the synaptic inputs were examined. KEY RESULTS Erythromycin (100 nmol L(-1), 1 μmol L(-1), 10 μmol L(-1)) significantly inhibited the frequency of glycinergic spontaneous inhibitory postsynaptic currents (sIPSCs) of GVMs and significantly inhibited the amplitude at the concentration of 10 μmol L(-1). These responses were prevented by GM-109, a selective motilin receptor antagonist. In the pre-existence of tetradotoxin (TTX, 1 μmol L(-1)), erythromycin (10 μmol L(-1)) caused significant decreases of the glycinergic miniature inhibitory postsynaptic currents (mIPSCs), in both the frequency and the amplitude. However, erythromycin (10 μmol L(-1)) didn't cause significant changes of the GABAergic sIPSCs. CONCLUSIONS & INFERENCES Erythromycin selectively inhibits the glycinergic inputs of GVMs.
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Affiliation(s)
- H Liu
- The State Key Laboratory of Medical Neurobiology and Institute of Brain Sciences, Fudan University Shanghai Medical College, Shanghai, China
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Sakahara S, Xie Z, Koike K, Hoshino S, Sakata I, Oda SI, Takahashi T, Sakai T. Physiological characteristics of gastric contractions and circadian gastric motility in the free-moving conscious house musk shrew (Suncus murinus). Am J Physiol Regul Integr Comp Physiol 2010; 299:R1106-13. [DOI: 10.1152/ajpregu.00278.2010] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Although many studies have demonstrated the physiological action of motilin on the migrating motor complex, the precise mechanisms remain obscure. To obtain new insights into the mechanisms, we focused on the house musk shrew ( Suncus murinus, suncus used as a laboratory name) as a small model animal for in vivo motilin study, and we studied the physiological characteristics of suncus gastrointestinal motility. Strain gauge transducers were implanted on the serosa of the gastric body and duodenum, and we recorded gastrointestinal contractions in the free-moving conscious suncus and also examined the effects of intravenous infusion of various agents on gastrointestinal motility. During the fasted state, the suncus stomach and duodenum showed clear migrating phase III contractions (intervals of 80–150 min) as found in humans and dogs. Motilin (bolus injection, 100–300 ng/kg; continuous infusion, 10–100 ng·kg−1·min−1) and erythromycin (80 μg·kg−1·min−1) induced gastric phase III contractions, and motilin injection also increased the gastric motility index in a dose-dependent manner ( P < 0.05, vs. saline). Pretreatment with atropine completely abolished the motilin-induced gastric phase III contractions. On the other hand, in the free-feeding condition, the suncus showed a relatively long fasting period in the light phase followed by spontaneous gastric phase III contractions. The results suggest that the suncus has almost the same gastrointestinal motility and motilin response as those found in humans and dogs, and we propose the suncus as a new small model animal for studying gastrointestinal motility and motilin in vivo.
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Affiliation(s)
- Satoshi Sakahara
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering and
| | - Zuoyun Xie
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering and
| | - Kanako Koike
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering and
| | - Satoya Hoshino
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering and
| | - Ichiro Sakata
- Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas; and
| | - Sen-ichi Oda
- Laboratory of Animal Management & Resources, School of Bio-Agricultural Sciences, Nagoya University, Nagoya, Japan
| | - Toku Takahashi
- Department of Surgery, Medical College of Wisconsin and Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin
| | - Takafumi Sakai
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering and
- Saitama University Brain Science Institute, Saitama University, Saitama
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Yang GK, Yip L, Fredholm BB, Kieffer TJ, Kwok YN. Involvement of adenosine signaling in controlling the release of ghrelin from the mouse stomach. J Pharmacol Exp Ther 2010; 336:77-86. [PMID: 20876230 DOI: 10.1124/jpet.110.171280] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ghrelin, a potent orexigenic hormone released from the stomach, is important in regulating energy metabolism. Abnormal ghrelin levels are associated with eating disorders and metabolic diseases. However, factors involved in the regulation of ghrelin release remain unclear. Here, we examined the involvement of adenosine signaling in the control of ghrelin release from the perfused mouse stomach. Adenosine stimulated ghrelin release concentration-dependently, and the A(2A) receptor-selective antagonists 4-(2-[7-amino-2-(2-furyl)[1,2,4]triazolo[2,3-a][1,3,5]triazin-5-ylamino]ethyl)phenol (ZM 241385) and 2-(2-furanyl)-7-(2-phenylethyl)-7H-pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidin-5-amine (SCH 58261) abolished the increased release. The A(2A) receptor-selective agonist 2-p-(2-carboxyethyl)phenethylamino-5-N-ethylcarboxamidoadenosine hydrochloride (CGS 21680) augmented ghrelin release concentration-dependently, whereas the A(1) receptor-selective agonist 2-chloro-N(6)-cyclopentyladenosine inhibited ghrelin release. In A(2A) receptor knockout mice, adenosine inhibited ghrelin release, and the A(1) receptor-selective antagonist 8-cyclopentyl-1,3-dipropylxanthine blocked this inhibition. The adenosine deaminase inhibitor erythro-9-(2-hydroxy-3-nonyl)adenine hydrochloride increased ghrelin release in wild-type and A(1) receptor knockout mice but not in A(2A) receptor knockout mice. Colocalization of ghrelin immunoreactivity with A(1) and A(2A) receptor immunoreactivities in the gastric nerve fibers were observed. Colocalization was also detected for ghrelin and A(1) receptor immunoreactivities in the gastric mucosa. Blockade of neural activities with tetrodotoxin abolished the stimulatory effect of adenosine on ghrelin release. In conclusion, adenosine exerts predominantly a tonic A(2A) receptor-mediated stimulatory action on gastric ghrelin release, whereas an A(1) receptor-mediated inhibitory action is also apparent when the tonic excitatory effect was removed.
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Affiliation(s)
- Gary K Yang
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada, V6T 1Z3
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Falkén Y, Hellström PM, Sanger GJ, Dewit O, Dukes G, Grybäck P, Holst JJ, Näslund E. Actions of prolonged ghrelin infusion on gastrointestinal transit and glucose homeostasis in humans. Neurogastroenterol Motil 2010; 22:e192-200. [PMID: 20100281 DOI: 10.1111/j.1365-2982.2009.01463.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND Ghrelin is produced by enteroendocrine cells in the gastric mucosa and stimulates gastric emptying in healthy volunteers and patients with gastroparesis in short-term studies. The aim of this study was to evaluate effects of intravenous ghrelin on gastrointestinal motility and glucose homeostasis during a 6-h infusion in humans. METHODS Ghrelin (15 pmol kg(-1) min(-1)) or saline was infused intravenously for 360 min after intake of radio-opaque markers, acetaminophen, and lactulose after a standardized breakfast in 12 male volunteers. Gastric emptying, orocecal transit, colonic transit, postprandial plasma concentrations of glucose, insulin, glucagon-like peptide-1 (GLP-1), and peptide YY were assessed. In vitro studies of gastrointestinal muscle contractility were performed. KEY RESULTS The gastric emptying rate was faster for ghrelin compared to saline (P = 0.002) with a shorter half-emptying time (50.3 +/- 3.9 vs 59.9 +/- 4.4 min, P = 0.004). There was no effect of ghrelin on orocecal or colonic transit. Postprandial elevations of plasma glucose, insulin, and GLP-1 occurred 15 min earlier and were higher with ghrelin. The insulinogenic index did not change during ghrelin infusion. Basal in vitro contractility was unaffected by ghrelin. CONCLUSIONS & INFERENCES The effect of a 6-h ghrelin infusion on gastrointestinal motility is limited to the stomach without affecting orocecal or colonic transit. Plasma glucose, insulin, and GLP-1 are elevated postprandially, probably as a result of the hastened gastric emptying. Changes in glucose homeostasis as a consequence of stimulated gastric emptying and hormone release, need to be taken into account in the use of pharmacological stimulants for the treatment of motility disorders.
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Affiliation(s)
- Y Falkén
- Division of Surgery, Department of Clinical Sciences, Danderyd Hospital, Karolinska Institute, SE-182 88 Stockholm, Sweden.
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Sjölund K, Ekman R, Wierup N. Covariation of plasma ghrelin and motilin in irritable bowel syndrome. Peptides 2010; 31:1109-12. [PMID: 20338210 DOI: 10.1016/j.peptides.2010.03.021] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Revised: 03/16/2010] [Accepted: 03/17/2010] [Indexed: 12/26/2022]
Abstract
We have previously shown that ghrelin is mainly localized to the stomach but also occurs, together with the prokinetic hormone motilin, in endocrine cells in the proximal small intestine. This study explored ghrelin and motilin concentrations in plasma in relation to gastrointestinal motility and whether plasma ghrelin is changed in patients with irritable bowel syndrome (IBS). Nine patients with severe IBS and 10 healthy subjects underwent stationary antro-duodeni-jejunal manometry; blood was sampled during similar motility phases in the two groups. The motility phases were monitored and blood samples were collected during fasting and after food intake. Plasma was analyzed for two forms of ghrelin (octanylated and desoctanylated) as well as for motilin. In IBS patients circulating motilin levels covaried with total ghrelin levels (r=0.90; p<0.004), octanylated ghrelin (r=0.77; p<0.02) and desoctanylated ghrelin (r=0.69; p<0.04). No such correlations were seen in the control group. Octanylated ghrelin comprised 35.3+/-3.9% (mean+/-SEM) of the total circulating ghrelin in the IBS patients compared to 40.4+/-4.5% (mean+/-SEM) in the control group (NS). Ghrelin covaried with motilin in plasma in IBS but not in plasma from healthy subjects. This suggests the two peptides act together in IBS.
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Affiliation(s)
- Kristina Sjölund
- Department of Internal Medicine, Trelleborg Hospital, Hedvägen 46, S-231 85 Trelleborg, Sweden.
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Chuai JR, Zhu YQ, Xu LX, Yuan F, An B, Xu YQ. Changes in serum ghrelin and small intestinal motility in rats with cerebral arterial thrombosis. Shijie Huaren Xiaohua Zazhi 2010; 18:1550-1554. [DOI: 10.11569/wcjd.v18.i15.1550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To determine the changes in serum ghrelin and small intestinal motility in rats with cerebral arterial thrombosis and to explore their relationship.
METHODS: Forty-eight Wistar rats were randomly divided into two groups: control group (n = 8) and middle cerebral artery occlusion (MCAO) group (n = 40). The MCAO group was further equally divided into 5 subgroups for testing at 3, 6, 12, 24 and 48 h after cerebral arterial thrombosis. MCAO was induced in rats using the thread occlusion method proposed by Longa. Neurologic examinations were conducted and neurologic findings were scored at each time point. Triphenyltetrazolium chloride (TTC) staining of brain tissue was performed. The content of serum ghrelin was determined by enzyme-linked immunosorbent assay, and small intestinal motility was measured by methylene blue staining. The ileum tissue was examined by light and electron microscopy.
RESULTS: The neurologic scores were 0 for all the rats in the control group and 1-3 for those in the MCAO group. Small intestinal motility was significantly lower in the MCAO group than in the control group (P < 0.05), reaching the lowest level at 24 h. Serum ghrelin level increased at 3 h and reached the peak at 24 h. Serum ghrelin level was significantly higher in the MCAO group than in the control group (P < 0.05). Correlation analysis showed a linear relationship between serum ghrelin levels and small intestinal motility (r = -0.841, P < 0.05) in rats with MCAO. Intestinal mucosal injury could be seen by light and electron microscopy, such as intestinal villus swelling, chondrosome swelling, vacuolar degeneration, apoptosis, etc.
CONCLUSION: Changes in serum ghrelin and small intestinal motility occur in rats with MCAO. The change of intestinal motility is significant at 24 h after cerebral ischemia.
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Ghrelin improves LPS-induced gastrointestinal motility disturbances: roles of NO and prostaglandin E2. Shock 2010; 33:205-12. [PMID: 19503023 DOI: 10.1097/shk.0b013e3181ae841b] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Ghrelin, an important orexigenic peptide, exerts gastroprokinetic and anti-inflammatory effects. We investigated the role of ghrelin in LPS-induced gastrointestinal (GI) motility disturbances through NO and prostaglandin E2 pathways in mice. Ghrelin-containing cells and its receptor, growth hormone secretagogue receptor 1 (GHSR-1), were localized in the stomach and duodenum using an immunohistochemical method. The distribution of ghrelin-containing cells or GHSR-1 immunoreactivity in both the mucosal and the muscle layers was heterogeneous within both tissues. The i.p. administration of ghrelin (1-20 microg/kg) had no effect on gastric emptying but markedly increased the GI transit (GIT) in normal mice. LPS (20 mg/kg i.p.)-treated mice showed significant decreases in the gastric emptying and GIT. Ghrelin attenuated the LPS-induced delay in gastric emptying and GIT. We also performed immunohistochemical experiments on both tissues. Immunohistochemistry showed the presence of iNOS and cyclooxygenase 2 in both tissues of LPS-treated mice. Treatment of LPS-exposed mice with ghrelin (20 microg/kg) diminished the presence of iNOS but not cyclooxygenase 2 in both tissues. The effect of ghrelin on regulating LPS-induced GI motility disturbance was further found to be associated with a reduction in iNOS expression in the GI tract and plasma NO overproduction rather than regulation of neural or endothelial NO synthase expression in the GI tissue. In addition, ghrelin was found to elevate prostaglandin E2 levels in the GI tissue but showed no significant change in LPS-treated mice. These findings indicate that the action of ghrelin binding to GHSR-1 improves endotoxemia-induced GI motility disturbances mainly through down-regulating the NO pathway in the GI tract.
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Nakamura T, Onaga T, Kitazawa T. Ghrelin stimulates gastric motility of the guinea pig through activation of a capsaicin-sensitive neural pathway: in vivo and in vitro functional studies. Neurogastroenterol Motil 2010; 22:446-52, e107. [PMID: 19840269 DOI: 10.1111/j.1365-2982.2009.01422.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND Ghrelin stimulates gastric motility in rats, mice and humans. Although ghrelin and the ghrelin receptor are known to be expressed in the guinea-pig gastrointestinal tract, the effects of ghrelin on gastric motility have not been examined. Aim of the present study was to clarify the motor-stimulating action of ghrelin in the guinea-pig stomach. METHODS Gastric motility was measured as intraluminal pressure changes using a balloon inserted in the stomach of urethane-anaesthetized guinea pigs. The effects of ghrelin on gastric muscle contraction and [(3)H]-efflux from [(3)H]-choline-loaded strips were investigated in vitro. KEY RESULTS Ghrelin (0.3-30 microg kg(-1), i.v.) increased gastric motility in a dose-dependent manner but des-acyl ghrelin was ineffective. The action of ghrelin was completely inhibited by hexamethonium and D-Lys(3)-growth-hormone releasing peptide-6. Atropine partially decreased the stimulatory action of ghrelin. In capsaicin-pretreated guinea pigs, the ghrelin-induced response was markedly decreased. Ghrelin (1 micromol L(-1)) did not affect [(3)H]-efflux in non-stimulated preparations but significantly decreased electrical field stimulation (EFS)-induced [(3)H]-efflux. L-Nitro arginine methylester (L-NAME) attenuated the inhibition of [(3)H]-efflux by ghrelin. Ghrelin did not cause any mechanical changes in gastric strips. Electrical field stimulation caused relaxation of gastric strips, which changed to atropine-sensitive contraction in the presence of L-NAME. Relaxation induced by EFS was slightly potentiated, but the EFS-induced contraction was not affected by ghrelin. CONCLUSIONS & INFERENCES Ghrelin stimulates gastric motility of the guinea pig through activation of capsaicin-sensitive vago-vagal reflex pathway including efferent cholinergic neurons. Peripheral ghrelin receptors on enteric nitrergic nerves might affect the ghrelin-induced gastric action by releasing nitric oxide.
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Affiliation(s)
- T Nakamura
- Department of Pharmacology, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido, Japan
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Veldhuis JD, Bowers CY. Integrating GHS into the Ghrelin System. INTERNATIONAL JOURNAL OF PEPTIDES 2010; 2010:879503. [PMID: 20798846 PMCID: PMC2925380 DOI: 10.1155/2010/879503] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Accepted: 12/30/2009] [Indexed: 12/21/2022]
Abstract
Oligopeptide derivatives of metenkephalin were found to stimulate growth-hormone (GH) release directly by pituitary somatotrope cells in vitro in 1977. Members of this class of peptides and nonpeptidyl mimetics are referred to as GH secretagogues (GHSs). A specific guanosine triphosphatate-binding protein-associated heptahelical transmembrane receptor for GHS was cloned in 1996. An endogenous ligand for the GHS receptor, acylghrelin, was identified in 1999. Expression of ghrelin and homonymous receptor occurs in the brain, pituitary gland, stomach, endothelium/vascular smooth muscle, pancreas, placenta, intestine, heart, bone, and other tissues. Principal actions of this peptidergic system include stimulation of GH release via combined hypothalamopituitary mechanisms, orexigenesis (appetitive enhancement), insulinostasis (inhibition of insulin secretion), cardiovascular effects (decreased mean arterial pressure and vasodilation), stimulation of gastric motility and acid secretion, adipogenesis with repression of fat oxidation, and antiapoptosis (antagonism of endothelial, neuronal, and cardiomyocyte death). The array of known and proposed interactions of ghrelin with key metabolic signals makes ghrelin and its receptor prime targets for drug development.
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Affiliation(s)
- Johannes D. Veldhuis
- Department of Medicine, Endocrine Research Unit, Mayo School of Graduate Medical Education, Clinical Translational Science Center, Mayo Clinic, Rochester, MN 55905, USA
| | - Cyril Y. Bowers
- Division of Endocrinology, Department of Internal Medicine, Tulane University Health Sciences Center, New Orleans, LA 70112, USA
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Castañeda TR, Tong J, Datta R, Culler M, Tschöp MH. Ghrelin in the regulation of body weight and metabolism. Front Neuroendocrinol 2010; 31:44-60. [PMID: 19896496 DOI: 10.1016/j.yfrne.2009.10.008] [Citation(s) in RCA: 243] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2009] [Revised: 10/26/2009] [Accepted: 10/26/2009] [Indexed: 12/25/2022]
Abstract
Ghrelin, a peptide hormone predominantly produced by the stomach, was isolated as the endogenous ligand for the growth hormone secretagogue receptor. Ghrelin is a potent stimulator of growth hormone (GH) secretion and is the only circulatory hormone known to potently enhance feeding and weight gain and to regulate energy homeostasis following central and systemic administration. Therapeutic intervention with ghrelin in catabolic situations may induce a combination of enhanced food intake, increased gastric emptying and nutrient storage, coupled with an increase in GH thereby linking nutrient partitioning with growth and repair processes. These qualities have fostered the idea that ghrelin-based compounds may have therapeutic utility in treating malnutrition and wasting induced by various sub-acute and chronic disorders. Conversely, compounds that inhibit ghrelin action may be useful for the prevention or treatment of metabolic syndrome components such as obesity, impaired lipid metabolism or insulin resistance. In recent years, the effects of ghrelin on glucose homeostasis, memory function and gastrointestinal motility have attracted considerable amount of attention and revealed novel therapeutic targets in treating a wide range of pathologic conditions. Furthermore, discovery of ghrelin O-acyltransferase has also opened new research opportunities that could lead to major understanding of ghrelin physiology. This review summarizes the current knowledge on ghrelin synthesis, secretion, mechanism of action and biological functions with an additional focus on potential for ghrelin-based pharmacotherapies.
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Affiliation(s)
- T R Castañeda
- Dept. of Physiology and Pharmacology, Center for Diabetes and Endocrine Research, College of Medicine, University of Toledo, Toledo, OH, USA
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