1
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Bruschetta G, Leonardi F, Licata P, Iannelli NM, Fernàndez-Parra R, Bruno F, Messina L, Costa GL. Oxidative stress in relation to serotonin under general anaesthesia in dogs undergoing ovariectomy. Vet Q 2024; 44:1-8. [PMID: 39028214 PMCID: PMC11262201 DOI: 10.1080/01652176.2024.2379319] [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: 03/07/2024] [Accepted: 07/03/2024] [Indexed: 07/20/2024] Open
Abstract
Abdominal surgery such as ovariectomy is a traumatic event that can cause oxidative stress. The aim of the present study was to evaluate the concentration of serotonin in relation to ovariectomy-induced oxidative stress in dogs undergoing general anesthesia. Thirty-two female dogs, under general anesthesia, received meloxicam before surgery (0.2 mgkg-1 SC) and after surgery (0.1 mgkg-1 OS every 24 h). The physiological, hematological, and biochemical parameters: glycemia, aspartate transaminase (AST), alanine aminotransferase (ALT), total protein, albumin and BUN were evaluated. Oxidative stress was determined by malondialdehyde (MDA) assay, catalase (CAT), superoxide dismutase (SOD), myeloperoxidase (MPO) and butyrylcholinesterase (BuChe) at baseline, 36 and 48 h after the last administration of meloxicam. Serotonin (5-HT) concentration was also evaluated at baseline, 36 and 48 h after the last administration of meloxicam. Responses to surgical stimulus were evaluated. Physiological and hematological parameters they fell within the normal ranges for anesthetized dogs. Glycemia increased, albumin levels decreased after surgery. No rescue analgesia was required. MDA and 5-HT concentrations significantly increased from the baseline at 36 and 48 h after surgery (p < .001). 5-HT levels could be used as an indicator for oxidative stress induced by surgery and it might be employed for objectively quantifying the well-being of the surgical patient.
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Affiliation(s)
| | - Fabio Leonardi
- Department of Veterinary Science, University of Parma, Parma, Italy
| | - Patrizia Licata
- Department of Veterinary Sciences, University of Messina, Messina, Italy
| | | | | | - Fabio Bruno
- Department of Veterinary Sciences, University of Messina, Messina, Italy
| | - Laura Messina
- Department of Veterinary Sciences, University of Messina, Messina, Italy
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2
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Spencer NJ, Kyloh MA, Travis L, Hibberd TJ. Identification of vagal afferent nerve endings in the mouse colon and their spatial relationship with enterochromaffin cells. Cell Tissue Res 2024; 396:313-327. [PMID: 38383905 PMCID: PMC11144134 DOI: 10.1007/s00441-024-03879-6] [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: 12/18/2023] [Accepted: 02/13/2024] [Indexed: 02/23/2024]
Abstract
Understanding how the gut communicates with the brain, via sensory nerves, is of significant interest to medical science. Enteroendocrine cells (EEC) that line the mucosa of the gastrointestinal tract release neurochemicals, including the largest quantity of 5-hydroxytryptamine (5-HT). How the release of substances, like 5-HT, from enterochromaffin (EC) cells activates vagal afferent nerve endings is unresolved. We performed anterograde labelling from nodose ganglia in vivo and identified vagal afferent axons and nerve endings in the mucosa of whole-mount full-length preparations of mouse colon. We then determined the spatial relationship between mucosal-projecting vagal afferent nerve endings and EC cells in situ using 3D imaging. The mean distances between vagal afferent nerve endings in the mucosa, or nearest varicosities along vagal afferent axon branches, and the nearest EC cell were 29.6 ± 19.2 μm (n = 107, N = 6) and 25.7 ± 15.2 μm (n = 119, N = 6), respectively. No vagal afferent endings made close contacts with EC cells. The distances between EC cells and vagal afferent endings are many hundreds of times greater than known distances between pre- and post-synaptic membranes (typically 10-20 nm) that underlie synaptic transmission in vertebrates. The absence of any close physical contacts between 5-HT-containing EC cells and vagal afferent nerve endings in the mucosa leads to the inescapable conclusion that the mechanism by which 5-HT release from ECs in the colonic mucosa occurs in a paracrine fashion, to activate vagal afferents.
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Affiliation(s)
- Nick J Spencer
- Visceral Neurophysiology Laboratory, Flinders Health and Medical Research Institute & College of Medicine and Public Health, Flinders University of South Australia, GPO Box 2100, Bedford Park, Adelaide, South Australia, 5042, Australia.
| | - Melinda A Kyloh
- Visceral Neurophysiology Laboratory, Flinders Health and Medical Research Institute & College of Medicine and Public Health, Flinders University of South Australia, GPO Box 2100, Bedford Park, Adelaide, South Australia, 5042, Australia
| | - Lee Travis
- Visceral Neurophysiology Laboratory, Flinders Health and Medical Research Institute & College of Medicine and Public Health, Flinders University of South Australia, GPO Box 2100, Bedford Park, Adelaide, South Australia, 5042, Australia
| | - Timothy J Hibberd
- Visceral Neurophysiology Laboratory, Flinders Health and Medical Research Institute & College of Medicine and Public Health, Flinders University of South Australia, GPO Box 2100, Bedford Park, Adelaide, South Australia, 5042, Australia
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3
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Yeoman MS, Fidalgo S, Marcelli G, Patel BA. Amperometry approach curve profiling to understand the regulatory mechanisms governing the concentration of intestinal extracellular serotonin. Sci Rep 2024; 14:10479. [PMID: 38714793 PMCID: PMC11076564 DOI: 10.1038/s41598-024-61296-9] [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: 12/28/2023] [Accepted: 05/03/2024] [Indexed: 05/10/2024] Open
Abstract
Enterochromaffin (EC) cells located within the intestinal mucosal epithelium release serotonin (5-HT) to regulate motility tones, barrier function and the immune system. Electroanalytical methodologies have been able to monitor steady state basal extracellular 5-HT levels but are unable to provide insight into how these levels are influenced by key regulatory processes such as release and uptake. We established a new measurement approach, amperometry approach curve profiling, which monitors the extracellular 5-HT level at different electrode-tissue (E-T) distances. Analysis of the current profile can provide information on contributions of regulatory components on the observed extracellular 5-HT level. Measurements were conducted from ex vivo murine ileum and colon using a boron-doped diamond (BDD) microelectrode. Amperometry approach curve profiling coupled with classical pharmacology demonstrated that extracellular 5-HT levels were significantly lower in the colon when compared to the ileum. This difference was due to a greater degree of activity of the 5-HT transporter (SERT) and a reduced amount of 5-HT released from colonic EC cells. The presence of an inhibitory 5-HT4 autoreceptor was observed in the colon, where a 40% increase in extracellular 5-HT was the half maximal inhibitory concentration for activation of the autoreceptor. This novel electroanalytical approach allows estimates of release and re-uptake and their contribution to 5-HT extracellular concentration from intestinal tissue be obtained from a single series of measurements.
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Affiliation(s)
- Mark S Yeoman
- School of Applied Sciences, University of Brighton, Huxley Building, Brighton, BN2 4GJ, UK
- Centre for Lifelong Health, University of Brighton, Huxley Building, Brighton, BN2 4GJ, UK
| | - Sara Fidalgo
- School of Applied Sciences, University of Brighton, Huxley Building, Brighton, BN2 4GJ, UK
- Centre for Lifelong Health, University of Brighton, Huxley Building, Brighton, BN2 4GJ, UK
| | - Gianluca Marcelli
- School of Engineering, University of Kent, Jennison Building, Canterbury, CT2 7NZ, UK
| | - Bhavik Anil Patel
- School of Applied Sciences, University of Brighton, Huxley Building, Brighton, BN2 4GJ, UK.
- Centre for Lifelong Health, University of Brighton, Huxley Building, Brighton, BN2 4GJ, UK.
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4
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Fricke HP, Krajco CJ, Perry MJ, Brettingen LJ, Wake LA, Charles JF, Hernandez LL. Fluoxetine treatment during the postpartal period may have short-term impacts on murine maternal skeletal physiology. Front Pharmacol 2023; 14:1244580. [PMID: 38074149 PMCID: PMC10701399 DOI: 10.3389/fphar.2023.1244580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 11/14/2023] [Indexed: 12/23/2023] Open
Abstract
Postpartum depression affects many individuals after parturition, and selective serotonin reuptake inhibitors (SSRIs) are often used as the first-line treatment; however, both SSRIs and lactation are independently associated with bone loss due to the role of serotonin in bone remodeling. Previously, we have established that administration of the SSRI fluoxetine during the peripartal period results in alterations in long-term skeletal characteristics. In the present study, we treated mice with either a low or high dose of fluoxetine during lactation to determine the consequences of the perturbation of serotonin signaling during this time period on the dam skeleton. We found that lactational fluoxetine exposure affected both cortical and trabecular parameters, altered gene expression and circulating markers of bone turnover, and affected mammary gland characteristics, and that these effects were more pronounced in the dams that were exposed to the low dose of fluoxetine in comparison to the high dose. Fluoxetine treatment during the postpartum period in rodents had short term effects on bone that were largely resolved 3 months post-weaning. Despite the overall lack of long-term insult to bone, the alterations in serotonin-driven lactational bone remodeling raises the question of whether fluoxetine is a safe option for the treatment of postpartum depression.
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Affiliation(s)
- Hannah P. Fricke
- Endocrinology and Reproductive Physiology Program, University of Wisconsin-Madison, Madison, WI, United States
- Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI, United States
| | - Chandler J. Krajco
- Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI, United States
| | - Molly J. Perry
- Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI, United States
| | - Lauren J. Brettingen
- Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI, United States
| | - Lella A. Wake
- Departments of Orthopedics and Medicine, Brigham and Women’s Hospital, Boston, MA, United States
| | - Julia F. Charles
- Departments of Orthopedics and Medicine, Brigham and Women’s Hospital, Boston, MA, United States
| | - Laura L. Hernandez
- Endocrinology and Reproductive Physiology Program, University of Wisconsin-Madison, Madison, WI, United States
- Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI, United States
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5
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Yu Y, Li YC, Zhang FC, Xu GY. Enterochromaffin Cell: Friend or Foe for Human Health? Neurosci Bull 2023; 39:1732-1734. [PMID: 37458959 PMCID: PMC10603001 DOI: 10.1007/s12264-023-01090-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 06/10/2023] [Indexed: 10/27/2023] Open
Affiliation(s)
- Yang Yu
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou, 215123, China
| | - Yong-Chang Li
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou, 215123, China
| | - Fu-Chao Zhang
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou, 215123, China
| | - Guang-Yin Xu
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou, 215123, China.
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6
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Fricke HP, Hernandez LL. The Serotonergic System and Bone Metabolism During Pregnancy and Lactation and the Implications of SSRI Use on the Maternal-Offspring Dyad. J Mammary Gland Biol Neoplasia 2023; 28:7. [PMID: 37086330 PMCID: PMC10122632 DOI: 10.1007/s10911-023-09535-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 04/06/2023] [Indexed: 04/23/2023] Open
Abstract
Lactation is a physiological adaptation of the class Mammalia and is a product of over 200 million years of evolution. During lactation, the mammary gland orchestrates bone metabolism via serotonin signaling in order to provide sufficient calcium for the offspring in milk. The role of serotonin in bone remodeling was first discovered over two decades ago, and the interplay between serotonin, lactation, and bone metabolism has been explored in the years following. It is estimated that postpartum depression affects 10-15% of the population, and selective serotonin reuptake inhibitors (SSRI) are often used as the first-line treatment. Studies conducted in humans, nonhuman primates, sheep, and rodents have provided evidence that there are consequences on both parent and offspring when serotonin signaling is disrupted during the peripartal period; however, the long-term consequences of disruption of serotonin signaling via SSRIs during the peripartal period on the maternal and offspring skeleton are not fully known. This review will focus on the relationship between the mammary gland, serotonin, and bone remodeling during the peripartal period and the skeletal consequences of the dysregulation of the serotonergic system in both human and animal studies.
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Affiliation(s)
- Hannah P Fricke
- Animal and Dairy Sciences Department, University of Wisconsin-Madison, Madison, WI, USA
| | - Laura L Hernandez
- Animal and Dairy Sciences Department, University of Wisconsin-Madison, Madison, WI, USA.
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7
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Brooks EL, Hussain KK, Kotecha K, Abdalla A, Patel BA. Three-Dimensional-Printed Electrochemical Multiwell Plates for Monitoring Food Intolerance from Intestinal Organoids. ACS Sens 2023; 8:712-720. [PMID: 36749605 DOI: 10.1021/acssensors.2c02245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Common symptoms of food intolerance are caused by chemical components within food that have a pharmacological activity to alter the motility of the gastrointestinal tract. Food intolerance is difficult to diagnose as it requires a long-term process of eliminating foods that are responsible for gastrointestinal symptoms. Enterochromaffin (EC) cells are key intestinal epithelium cells that respond to luminal chemical stimulants by releasing 5-HT. Changes in 5-HT levels have been shown to directly alter the motility of the intestinal tract. Therefore, a rapid approach for monitoring the impact of chemicals in food components on 5-HT levels can provide a personalized insight into food intolerance and help stratify diets. Within this study, we developed a three-dimensional (3D)-printed electrochemical multiwell plate to determine changes in 5-HT levels from intestinal organoids that were exposed to varying chemical components found in food. The carbon black/poly-lactic acid (CB/PLA) electrodes had a linear range in physiological concentrations of 5-HT (0.1-2 μM) with a limit of detection of 0.07 μM. The electrodes were stable for monitoring 5-HT overflow from intestinal organoids. Using the electrochemical multiwell plate containing intestinal organoids, increases in 5-HT were observed in the presence of 0.1 mM cinnamaldehyde and 10 mM quercetin but reduction in 5-HT levels was observed in 1 mM sorbitol when compared to control. These changes in the presence of chemicals commonly found in food were verified with ex vivo ileum tissue measurements using chromatography and amperometry with boron-doped diamond electrodes. Overall, our 3D electrochemical multiwell plate measurements with intestinal organoids highlight an approach that can be a high-throughput platform technology for rapid screening of food intolerance to provide personalized nutritional diet.
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Affiliation(s)
- Emily L Brooks
- School of Applied Sciences, University of Brighton, Brighton BN2 4GJ, U.K.,Centre of Stress and Age-Related Diseases, University of Brighton, Brighton BN2 4GJ, U.K
| | - Khalil K Hussain
- School of Applied Sciences, University of Brighton, Brighton BN2 4GJ, U.K.,Centre of Stress and Age-Related Diseases, University of Brighton, Brighton BN2 4GJ, U.K
| | - Khushboo Kotecha
- School of Applied Sciences, University of Brighton, Brighton BN2 4GJ, U.K
| | - Aya Abdalla
- School of Applied Sciences, University of Brighton, Brighton BN2 4GJ, U.K.,Centre of Stress and Age-Related Diseases, University of Brighton, Brighton BN2 4GJ, U.K
| | - Bhavik Anil Patel
- School of Applied Sciences, University of Brighton, Brighton BN2 4GJ, U.K.,Centre of Stress and Age-Related Diseases, University of Brighton, Brighton BN2 4GJ, U.K
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8
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Kola JB, Docsa T, Uray K. Mechanosensing in the Physiology and Pathology of the Gastrointestinal Tract. Int J Mol Sci 2022; 24:ijms24010177. [PMID: 36613619 PMCID: PMC9820522 DOI: 10.3390/ijms24010177] [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: 10/02/2022] [Revised: 12/10/2022] [Accepted: 12/17/2022] [Indexed: 12/24/2022] Open
Abstract
Normal gastrointestinal function relies on sensing and transducing mechanical signals into changes in intracellular signaling pathways. Both specialized mechanosensing cells, such as certain enterochromaffin cells and enteric neurons, and non-specialized cells, such as smooth muscle cells, interstitial cells of Cajal, and resident macrophages, participate in physiological and pathological responses to mechanical signals in the gastrointestinal tract. We review the role of mechanosensors in the different cell types of the gastrointestinal tract. Then, we provide several examples of the role of mechanotransduction in normal physiology. These examples highlight the fact that, although these responses to mechanical signals have been known for decades, the mechanosensors involved in these responses to mechanical signals are largely unknown. Finally, we discuss several diseases involving the overstimulation or dysregulation of mechanotransductive pathways. Understanding these pathways and identifying the mechanosensors involved in these diseases may facilitate the identification of new drug targets to effectively treat these diseases.
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Affiliation(s)
- Job Baffin Kola
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
- Center of Excellence, The Hungarian Academy of Sciences, 4032 Debrecen, Hungary
| | - Tibor Docsa
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
- Center of Excellence, The Hungarian Academy of Sciences, 4032 Debrecen, Hungary
| | - Karen Uray
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
- Center of Excellence, The Hungarian Academy of Sciences, 4032 Debrecen, Hungary
- Correspondence:
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9
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Tuck CJ, Abu Omar A, De Palma G, Osman S, Jiménez-Vargas NN, Yu Y, Bennet SM, Lopez-Lopez C, Jaramillo-Polanco JO, Baker CC, Bennett AS, Guzman-Rodriguez M, Tsang Q, Alward T, Rolland S, Morissette C, Verdu EF, Bercik P, Vanner SJ, Lomax AE, Reed DE. Changes in signalling from faecal neuroactive metabolites following dietary modulation of IBS pain. Gut 2022; 72:gutjnl-2022-327260. [PMID: 36591617 DOI: 10.1136/gutjnl-2022-327260] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 11/23/2022] [Indexed: 01/03/2023]
Abstract
OBJECTIVE Dietary therapies for irritable bowel syndrome (IBS) have received increasing interest but predicting which patients will benefit remains a challenge due to a lack of mechanistic insight. We recently found evidence of a role for the microbiota in dietary modulation of pain signalling in a humanised mouse model of IBS. This randomised cross-over study aimed to test the hypothesis that pain relief following reduced consumption of fermentable carbohydrates is the result of changes in luminal neuroactive metabolites. DESIGN IBS (Rome IV) participants underwent four trial periods: two non-intervention periods, followed by a diet low (LFD) and high in fermentable carbohydrates for 3 weeks each. At the end of each period, participants completed questionnaires and provided stool. The effects of faecal supernatants (FS) collected before (IBS FS) and after a LFD (LFD FS) on nociceptive afferent neurons were assessed in mice using patch-clamp and ex vivo colonic afferent nerve recording techniques. RESULTS Total IBS symptom severity score and abdominal pain were reduced by the LFD (N=25; p<0.01). Excitability of neurons was increased in response to IBS FS, but this effect was reduced (p<0.01) with LFD FS from pain-responders. IBS FS from pain-responders increased mechanosensitivity of nociceptive afferent nerve axons (p<0.001), an effect lost following LFD FS administration (p=NS) or when IBS FS was administered in the presence of antagonists of histamine receptors or protease inhibitors. CONCLUSIONS In a subset of IBS patients with improvement in abdominal pain following a LFD, there is a decrease in pronociceptive signalling from FS, suggesting that changes in luminal mediators may contribute to symptom response.
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Affiliation(s)
- Caroline J Tuck
- Department of Sport, Exercise and Nutrition Sciences, La Trobe University, Melbourne, Victoria, Australia
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Amal Abu Omar
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
- Department of Physiology, Jordan University of Science and Technology, Irbid, Jordan
| | - Giada De Palma
- Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | - Samira Osman
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | | | - Yang Yu
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Sean Mp Bennet
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Cintya Lopez-Lopez
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | | | - Corey C Baker
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Aidan Sw Bennett
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | | | - Quentin Tsang
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Taylor Alward
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Sebastien Rolland
- Department of Medicine, Hopital Maisonneuve-Rosemont, Montreal, Québec, Canada
| | - Celine Morissette
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Elena F Verdu
- Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | - Premysl Bercik
- Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | - Stephen J Vanner
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Alan E Lomax
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - David E Reed
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
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10
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Spencer NJ, Keating DJ. Role of 5-HT in the enteric nervous system and enteroendocrine cells. Br J Pharmacol 2022. [PMID: 35861711 DOI: 10.1111/bph.15930] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 07/09/2022] [Accepted: 07/12/2022] [Indexed: 11/29/2022] Open
Abstract
Since the 1950s, considerable circumstantial evidence had been presented that endogenous 5-HT (serotonin) synthesized from within the wall of the gastrointestinal (GI) tract played an important role in GI motility and transit. However, identifying the precise functional role of gut-derived 5-HT has been difficult to ascertain, for a number of reasons. Over the past decade, as recording techniques have advanced significantly and access to new genetically modified animals improved, there have been major new insights and major changes in our understanding of the functional role of endogenous 5-HT in the GI tract. Data from many different laboratories have shown that major patterns of GI motility and transit still occur with minor or no, change when all endogenous 5-HT is pharmacologically or genetically ablated from the gut. Furthermore, antagonists of 5-HT3 receptors are equally, or more potent at inhibiting GI motility in segments of intestine that are completely depleted of endogenous 5-HT. Here, the most recent findings are discussed with regard to the functional role of endogenous 5-HT in enterochromaffin cells and enteric neurons in gut motility and more broadly in some major homeostatic pathways.
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Affiliation(s)
- Nick J Spencer
- College of Medicine and Public Health and Centre for Neuroscience, Flinders University of South Australia, Adelaide, Australia
| | - Damien J Keating
- College of Medicine and Public Health and Centre for Neuroscience, Flinders University of South Australia, Adelaide, Australia
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11
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A tissue-like neurotransmitter sensor for the brain and gut. Nature 2022; 606:94-101. [PMID: 35650358 DOI: 10.1038/s41586-022-04615-2] [Citation(s) in RCA: 123] [Impact Index Per Article: 61.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 03/04/2022] [Indexed: 12/24/2022]
Abstract
Neurotransmitters play essential roles in regulating neural circuit dynamics both in the central nervous system as well as at the peripheral, including the gastrointestinal tract1-3. Their real-time monitoring will offer critical information for understanding neural function and diagnosing disease1-3. However, bioelectronic tools to monitor the dynamics of neurotransmitters in vivo, especially in the enteric nervous systems, are underdeveloped. This is mainly owing to the limited availability of biosensing tools that are capable of examining soft, complex and actively moving organs. Here we introduce a tissue-mimicking, stretchable, neurochemical biological interface termed NeuroString, which is prepared by laser patterning of a metal-complexed polyimide into an interconnected graphene/nanoparticle network embedded in an elastomer. NeuroString sensors allow chronic in vivo real-time, multichannel and multiplexed monoamine sensing in the brain of behaving mouse, as well as measuring serotonin dynamics in the gut without undesired stimulations and perturbing peristaltic movements. The described elastic and conformable biosensing interface has broad potential for studying the impact of neurotransmitters on gut microbes, brain-gut communication and may ultimately be extended to biomolecular sensing in other soft organs across the body.
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12
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Jones LA, Jin B, Martin AM, Wei L, Ro S, Keating DJ. Diminished Piezo2-Dependent Tactile Sensitivity Occurs in Aging Human Gut and Slows Gastrointestinal Transit in Mice. Gastroenterology 2022; 162:1755-1757.e2. [PMID: 35122761 DOI: 10.1053/j.gastro.2022.01.043] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 01/20/2022] [Accepted: 01/21/2022] [Indexed: 12/02/2022]
Affiliation(s)
- Lauren A Jones
- Flinders Health and Medical Research Institute, Flinders University, South Australia, Australia
| | - Byungchang Jin
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, Nevada
| | - Alyce M Martin
- Flinders Health and Medical Research Institute, Flinders University, South Australia, Australia
| | - Lai Wei
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, Nevada
| | | | - Seungil Ro
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, Nevada
| | - Damien J Keating
- Flinders Health and Medical Research Institute, Flinders University, South Australia, Australia.
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13
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Mercado-Perez A, Beyder A. Gut feelings: mechanosensing in the gastrointestinal tract. Nat Rev Gastroenterol Hepatol 2022; 19:283-296. [PMID: 35022607 PMCID: PMC9059832 DOI: 10.1038/s41575-021-00561-y] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/22/2021] [Indexed: 12/11/2022]
Abstract
The primary function of the gut is to procure nutrients. Synchronized mechanical activities underlie nearly all its endeavours. Coordination of mechanical activities depends on sensing of the mechanical forces, in a process called mechanosensation. The gut has a range of mechanosensory cells. They function either as specialized mechanoreceptors, which convert mechanical stimuli into coordinated physiological responses at the organ level, or as non-specialized mechanosensory cells that adjust their function based on the mechanical state of their environment. All major cell types in the gastrointestinal tract contain subpopulations that act as specialized mechanoreceptors: epithelia, smooth muscle, neurons, immune cells, and others. These cells are tuned to the physical properties of the surrounding tissue, so they can discriminate mechanical stimuli from the baseline mechanical state. The importance of gastrointestinal mechanosensation has long been recognized, but the latest discoveries of molecular identities of mechanosensors and technical advances that resolve the relevant circuitry have poised the field to make important intellectual leaps. This Review describes the mechanical factors relevant for normal function, as well as the molecules, cells and circuits involved in gastrointestinal mechanosensing. It concludes by outlining important unanswered questions in gastrointestinal mechanosensing.
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Affiliation(s)
- Arnaldo Mercado-Perez
- Enteric NeuroScience Program (ENSP), Division of Gastroenterology & Hepatology, Mayo Clinic, Rochester, MN, USA
- Medical Scientist Training Program (MSTP), Mayo Clinic, Rochester, MN, USA
| | - Arthur Beyder
- Enteric NeuroScience Program (ENSP), Division of Gastroenterology & Hepatology, Mayo Clinic, Rochester, MN, USA.
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN, USA.
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14
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Enteric neuroimmune interactions coordinate intestinal responses in health and disease. Mucosal Immunol 2022; 15:27-39. [PMID: 34471248 PMCID: PMC8732275 DOI: 10.1038/s41385-021-00443-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 08/02/2021] [Accepted: 08/05/2021] [Indexed: 02/04/2023]
Abstract
The enteric nervous system (ENS) of the gastrointestinal (GI) tract interacts with the local immune system bidirectionally. Recent publications have demonstrated that such interactions can maintain normal GI functions during homeostasis and contribute to pathological symptoms during infection and inflammation. Infection can also induce long-term changes of the ENS resulting in the development of post-infectious GI disturbances. In this review, we discuss how the ENS can regulate and be regulated by immune responses and how such interactions control whole tissue physiology. We also address the requirements for the proper regeneration of the ENS and restoration of GI function following the resolution of infection.
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15
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Uray IP, Uray K. Mechanotransduction at the Plasma Membrane-Cytoskeleton Interface. Int J Mol Sci 2021; 22:11566. [PMID: 34768998 PMCID: PMC8584042 DOI: 10.3390/ijms222111566] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/19/2021] [Accepted: 10/21/2021] [Indexed: 02/08/2023] Open
Abstract
Mechanical cues are crucial for survival, adaptation, and normal homeostasis in virtually every cell type. The transduction of mechanical messages into intracellular biochemical messages is termed mechanotransduction. While significant advances in biochemical signaling have been made in the last few decades, the role of mechanotransduction in physiological and pathological processes has been largely overlooked until recently. In this review, the role of interactions between the cytoskeleton and cell-cell/cell-matrix adhesions in transducing mechanical signals is discussed. In addition, mechanosensors that reside in the cell membrane and the transduction of mechanical signals to the nucleus are discussed. Finally, we describe two examples in which mechanotransduction plays a significant role in normal physiology and disease development. The first example is the role of mechanotransduction in the proliferation and metastasis of cancerous cells. In this system, the role of mechanotransduction in cellular processes, including proliferation, differentiation, and motility, is described. In the second example, the role of mechanotransduction in a mechanically active organ, the gastrointestinal tract, is described. In the gut, mechanotransduction contributes to normal physiology and the development of motility disorders.
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Affiliation(s)
- Iván P. Uray
- Department of Clinical Oncology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary;
| | - Karen Uray
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
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16
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Joly A, Leulier F, De Vadder F. Microbial Modulation of the Development and Physiology of the Enteric Nervous System. Trends Microbiol 2020; 29:686-699. [PMID: 33309188 DOI: 10.1016/j.tim.2020.11.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 11/11/2020] [Accepted: 11/13/2020] [Indexed: 12/15/2022]
Abstract
The gastrointestinal tract harbors an intrinsic neuronal network, the enteric nervous system (ENS). The ENS controls motility, fluid homeostasis, and blood flow, but also interacts with other components of the intestine such as epithelial and immune cells. Recent studies indicate that gut microbiota diversification, which occurs alongside postnatal ENS maturation, could be critical for the development and function of the ENS. Here we discuss the possibility that this functional relationship starts in utero, whereby the maternal microbiota would prime the developing ENS and shape its physiology. We review ENS/microbiota interactions and their modulation in physiological and pathophysiological contexts. While microbial modulation of the ENS physiology is now well established, further studies are required to understand the contribution of the gut microbiota to the development and pathology of the ENS and to reveal the precise mechanisms underlying microbiota-to-ENS communications.
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Affiliation(s)
- Amélie Joly
- Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, École Normale Supérieure de Lyon, Centre National de la Recherche Scientifique, Université Claude Bernard Lyon 1, UMR5242, Lyon, France
| | - François Leulier
- Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, École Normale Supérieure de Lyon, Centre National de la Recherche Scientifique, Université Claude Bernard Lyon 1, UMR5242, Lyon, France
| | - Filipe De Vadder
- Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, École Normale Supérieure de Lyon, Centre National de la Recherche Scientifique, Université Claude Bernard Lyon 1, UMR5242, Lyon, France.
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17
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Lee HA, Ju Moon S, Yoo H, Kyung Kim M, Bok Jang S, Lee S, Kim S, Lee H. YH12852, a Potent and Selective Receptor Agonist of 5-hydroxytryptamine, Increased Gastrointestinal Motility in Healthy Volunteers and Patients With Functional Constipation. Clin Transl Sci 2020; 14:625-634. [PMID: 33202093 PMCID: PMC7993265 DOI: 10.1111/cts.12924] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 10/07/2020] [Indexed: 12/23/2022] Open
Abstract
Gastrointestinal (GI) motility disorders are common, decreases quality of life, and imposes a substantial economic burden. YH12852 is a novel agonist of 5‐hydroxytryptamine for the treatment of GI motility disorders. This phase I/IIa study assessed the tolerability, pharmacodynamic (PD) and pharmacokinetic (PK) profiles of YH12852. In the multiple dose (MD) cohort, healthy subjects and patients with functional constipation were randomized and received orally YH12852 at 0.3, 0.5, 1, 2, or 3 mg or prucalopride 2 mg or their matching placebo, once daily for 14 days after breakfast. In the multiple low‐dose cohort (MLD), healthy subjects randomly received once‐daily oral doses of YH12852 at 0.05 or 0.1 mg for 14 days after breakfast. Questionnaires, gastric emptying breath test for PDs, and plasma samples for PKs were collected. In the MD cohort, a total of 56 subjects (29 healthy volunteers and 27 patients with functional constipation) were randomized, of whom 48 completed the study. In the MLD cohort, a total of 16 healthy subjects were randomized, and 15 subjects completed the study. YH12852 increased the average weekly frequency of spontaneous bowel movements and loosened the stool. In addition, YH12852 increased quality of life satisfaction, and decreased severity of constipation symptom and GI symptoms. YH12852 was safe and well‐tolerated up to 3 mg and showed nearly dose proportional PKs. In conclusion, YH12852 was safe and enhanced GI motility. YH12852 can be developed as an effective treatment option for GI motility disorders, including functional constipation. Further studies are warranted to confirm this possibility.
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Affiliation(s)
- Hyun A Lee
- Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul, Korea.,Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, Korea
| | - Seol Ju Moon
- Center for Clinical Pharmacology, Biomedical Research Institute, Chonbuk National University Hospital, Jeonju, Korea
| | - Hyounggyoon Yoo
- Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul, Korea
| | - Mi Kyung Kim
- Yuhan Research & Development Institute, Yuhan Corporation, Seoul, Korea
| | - Seong Bok Jang
- Yuhan Research & Development Institute, Yuhan Corporation, Seoul, Korea
| | - Seoungoh Lee
- Yuhan Research & Development Institute, Yuhan Corporation, Seoul, Korea
| | - Sohee Kim
- Yuhan Research & Development Institute, Yuhan Corporation, Seoul, Korea
| | - Howard Lee
- Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul, Korea.,Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, Korea.,Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, Korea
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18
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Spencer NJ, Hu H. Enteric nervous system: sensory transduction, neural circuits and gastrointestinal motility. Nat Rev Gastroenterol Hepatol 2020; 17:338-351. [PMID: 32152479 PMCID: PMC7474470 DOI: 10.1038/s41575-020-0271-2] [Citation(s) in RCA: 271] [Impact Index Per Article: 67.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/27/2020] [Indexed: 02/07/2023]
Abstract
The gastrointestinal tract is the only internal organ to have evolved with its own independent nervous system, known as the enteric nervous system (ENS). This Review provides an update on advances that have been made in our understanding of how neurons within the ENS coordinate sensory and motor functions. Understanding this function is critical for determining how deficits in neurogenic motor patterns arise. Knowledge of how distension or chemical stimulation of the bowel evokes sensory responses in the ENS and central nervous system have progressed, including critical elements that underlie the mechanotransduction of distension-evoked colonic peristalsis. Contrary to original thought, evidence suggests that mucosal serotonin is not required for peristalsis or colonic migrating motor complexes, although it can modulate their characteristics. Chemosensory stimuli applied to the lumen can release substances from enteroendocrine cells, which could subsequently modulate ENS activity. Advances have been made in optogenetic technologies, such that specific neurochemical classes of enteric neurons can be stimulated. A major focus of this Review will be the latest advances in our understanding of how intrinsic sensory neurons in the ENS detect and respond to sensory stimuli and how these mechanisms differ from extrinsic sensory nerve endings in the gut that underlie the gut-brain axis.
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Affiliation(s)
- Nick J Spencer
- College of Medicine and Public Health & Centre for Neuroscience, Flinders University, Adelaide, Australia.
| | - Hongzhen Hu
- Department of Anesthesiology, The Center for the Study of Itch, Washington University School of Medicine, St Louis, MO, USA
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19
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The ever-changing roles of serotonin. Int J Biochem Cell Biol 2020; 125:105776. [PMID: 32479926 DOI: 10.1016/j.biocel.2020.105776] [Citation(s) in RCA: 95] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 05/25/2020] [Accepted: 05/26/2020] [Indexed: 12/14/2022]
Abstract
Serotonin (5-HT) has traditional roles as a key neurotransmitter in the central nervous system and as a regulatory hormone controlling a broad range of physiological functions. Perhaps the most classically-defined functions of 5-HT are centrally in the control of mood, sleep and anxiety and peripherally in the modulation of gastrointestinal motility. A more recently appreciated role for 5-HT has emerged, however, as an important metabolic hormone contributing to glucose homeostasis and adiposity, with a causal relationship existing between circulating 5-HT levels and metabolic diseases. Almost all peripheral 5-HT is derived from specialised enteroendocrine cells, called enterochromaffin (EC) cells, located throughout the length of the lining of the gastrointestinal tract. EC cells are important luminal sensory cells that can detect and respond to an array of ingested nutrients, as well as luminal gut microbiota and their associated metabolites. Intriguingly, the interaction between gut microbiota and EC cells is dynamic in nature and has strong implications for host physiology. In this review, we discuss the traditional and modern functions of 5-HT and highlight an emerging pathway by which gut microbiota influences host health. Serotonin, also known as 5-hydroxytryptamine (5-HT), is an important neurotransmitter, growth factor and hormone that mediates a range of physiological functions. In mammals, serotonin is synthesized from the essential amino acid tryptophan by the rate-limiting enzyme tryptophan hydroxylase (TPH), for which there are two isoforms expressed in distinct cell types throughout the body. Tph1 is mainly expressed by specialized gut endocrine cells known as enterochromaffin (EC) cells and by other non-neuronal cell types such as adipocytes (Walther et al., 2003). Tph2 is primarily expressed in neurons of the raphe nuclei of the brain stem and a subset of neurons in the enteric nervous system (ENS) (Yabut et al., 2019). As 5-HT cannot readily cross the blood-brain barrier, the central and peripheral pools of 5-HT are anatomically separated and as such, act in their own distinct manners (Martin et al., 2017c). In this review we discuss the peripheral roles of serotonin, with particular focus on the interaction of gut-derived serotonin with the gut microbiota, and address emerging evidence linking this relationship with host homeostasis.
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20
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Liu YL, Chen Y, Fan WT, Cao P, Yan J, Zhao XZ, Dong WG, Huang WH. Mechanical Distension Induces Serotonin Release from Intestine as Revealed by Stretchable Electrochemical Sensing. Angew Chem Int Ed Engl 2020; 59:4075-4081. [PMID: 31829491 DOI: 10.1002/anie.201913953] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 12/04/2019] [Indexed: 12/17/2022]
Abstract
The role of endogenous serotonin (5-HT) in gastrointestinal motility is still highly controversial. Although electrochemical techniques allow for direct and real-time recording of biomolecules, the dynamic monitoring of 5-HT release from elastic and tubular intestine during motor reflexes remains a great challenge because of the specific peristalsis patterns and inevitable passivation of the sensing interface. A stretchable sensor with antifouling and decontamination properties was assembled from gold nanotubes, titanium dioxide nanoparticles, and carbon nanotubes. The sandwich-like structure endowed the sensor with satisfying mechanical stability and electrochemical performance, high resistance against physical adsorption, and superior efficiency in the photodegradation of biofouling molecules. Insertion of the sensor into the lumen of rat ileum (the last section of the small intestine) successfully mimics intestinal peristalsis, and simultaneous real-time monitoring of distension-evoked 5-HT release was possible for the first time. Our results unambiguously reveal that mechanical distension of the intestine induces endogenous 5-HT overflow, and 5-HT level is closely associated with the physiological or pathological states of the intestine.
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Affiliation(s)
- Yan-Ling Liu
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
| | - Yan Chen
- Key Laboratory of Hubei Province for Digestive System Disease, Department of Gastroenterology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Wen-Ting Fan
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
| | - Pan Cao
- Key Laboratory of Hubei Province for Digestive System Disease, Department of Gastroenterology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Jing Yan
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
| | - Xing-Zhong Zhao
- Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan, 430072, China
| | - Wei-Guo Dong
- Key Laboratory of Hubei Province for Digestive System Disease, Department of Gastroenterology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Wei-Hua Huang
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
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21
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Liu Y, Chen Y, Fan W, Cao P, Yan J, Zhao X, Dong W, Huang W. Mechanical Distension Induces Serotonin Release from Intestine as Revealed by Stretchable Electrochemical Sensing. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201913953] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Yan‐Ling Liu
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education) College of Chemistry and Molecular Sciences Wuhan University Wuhan 430072 China
| | - Yan Chen
- Key Laboratory of Hubei Province for Digestive System Disease Department of Gastroenterology Renmin Hospital of Wuhan University Wuhan 430060 China
| | - Wen‐Ting Fan
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education) College of Chemistry and Molecular Sciences Wuhan University Wuhan 430072 China
| | - Pan Cao
- Key Laboratory of Hubei Province for Digestive System Disease Department of Gastroenterology Renmin Hospital of Wuhan University Wuhan 430060 China
| | - Jing Yan
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education) College of Chemistry and Molecular Sciences Wuhan University Wuhan 430072 China
| | - Xing‐Zhong Zhao
- Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education School of Physics and Technology Wuhan University Wuhan 430072 China
| | - Wei‐Guo Dong
- Key Laboratory of Hubei Province for Digestive System Disease Department of Gastroenterology Renmin Hospital of Wuhan University Wuhan 430060 China
| | - Wei‐Hua Huang
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education) College of Chemistry and Molecular Sciences Wuhan University Wuhan 430072 China
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22
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Hao MM, Fung C, Boesmans W, Lowette K, Tack J, Vanden Berghe P. Development of the intrinsic innervation of the small bowel mucosa and villi. Am J Physiol Gastrointest Liver Physiol 2020; 318:G53-G65. [PMID: 31682159 DOI: 10.1152/ajpgi.00264.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Detection of nutritional and noxious food components in the gut is a crucial component of gastrointestinal function. Contents in the gut lumen interact with enteroendocrine cells dispersed throughout the gut epithelium. Enteroendocrine cells release many different hormones, neuropeptides, and neurotransmitters that communicate either directly or indirectly with the central nervous system and the enteric nervous system, a network of neurons and glia located within the gut wall. Several populations of enteric neurons extend processes that innervate the gastrointestinal lamina propria; however, how these processes develop and begin to transmit information from the mucosa is not fully understood. In this study, we found that Tuj1-immunoreactive neurites begin to project out of the myenteric plexus at embryonic day (E)13.5 in the mouse small intestine, even before the formation of villi. Using live calcium imaging, we discovered that neurites were capable of transmitting electrical information from stimulated villi to the plexus by E15.5. In unpeeled gut preparations where all layers were left intact, we also mimicked the basolateral release of 5-HT from enteroendocrine cells, which triggered responses in myenteric cell bodies at postnatal day (P)0. Altogether, our results show that enteric neurons extend neurites out of the myenteric plexus early during mouse enteric nervous system development, innervating the gastrointestinal mucosa, even before villus formation in mice of either sex. Neurites are already able to conduct electrical information at E15.5, and responses to 5-HT develop postnatally.NEW & NOTEWORTHY How enteric neurons project into the gut mucosa and begin to communicate with the epithelium during development is not known. Our study shows that enteric neurites project into the lamina propria as early as E13.5 in the mouse, before development of the submucous plexus and before formation of intestinal villi. These neurites are capable of transmitting electrical signals back to their cell bodies by E15.5 and respond to serotonin applied to neurite terminals by birth.
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Affiliation(s)
- Marlene M Hao
- Laboratory for Enteric Neuroscience, Translational Research Center for Gastrointestinal Disorders, University of Leuven, Belgium.,Department of Anatomy and Neuroscience, the University of Melbourne, Australia
| | - Candice Fung
- Laboratory for Enteric Neuroscience, Translational Research Center for Gastrointestinal Disorders, University of Leuven, Belgium
| | - Werend Boesmans
- Laboratory for Enteric Neuroscience, Translational Research Center for Gastrointestinal Disorders, University of Leuven, Belgium.,Department of Pathology, GROW, School for Oncology and Developmental Biology, Maastricht University Medical Center, The Netherlands.,Biomedical Research Institute, Hasselt University, Hasselt, Belgium
| | - Katrien Lowette
- Laboratory for Enteric Neuroscience, Translational Research Center for Gastrointestinal Disorders, University of Leuven, Belgium
| | - Jan Tack
- Laboratory for Enteric Neuroscience, Translational Research Center for Gastrointestinal Disorders, University of Leuven, Belgium
| | - Pieter Vanden Berghe
- Laboratory for Enteric Neuroscience, Translational Research Center for Gastrointestinal Disorders, University of Leuven, Belgium
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23
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Tang C, Ksiazek I, Siccardi N, Gapp B, Weber D, Wirsching J, Beck V, Reist M, Gaudet L, Stuber N, Surber SS, Mao X, Nicholson TB, Carbone W, Beibel M, Roma G, Gubser Keller C, Bassilana F. UTS2B Defines a Novel Enteroendocrine Cell Population and Regulates GLP-1 Secretion Through SSTR5 in Male Mice. Endocrinology 2019; 160:2849-2860. [PMID: 31556942 DOI: 10.1210/en.2019-00549] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 09/20/2019] [Indexed: 12/25/2022]
Abstract
The gut-pancreas axis plays a key role in the regulation of glucose homeostasis and may be therapeutically exploited to treat not only type 2 diabetes but also hypoglycemia and hyperinsulinemia. We identify a novel enteroendocrine cell type expressing the peptide hormone urotensin 2B (UTS2B). UTS2B inhibits glucagon-like peptide-1 (GLP-1) secretion in mouse intestinal crypts and organoids, not by signaling through its cognate receptor UTS2R but through the activation of the somatostatin receptor (SSTR) 5. Circulating UTS2B concentrations in mice are physiologically regulated during starvation, further linking this peptide hormone to metabolism. Furthermore, administration of UTS2B to starved mice demonstrates that it is capable of regulating blood glucose and plasma concentrations of GLP-1 and insulin in vivo. Altogether, our results identify a novel cellular source of UTS2B in the gut, which acts in a paracrine manner to regulate GLP-1 secretion through SSTR5. These findings uncover a fine-tuning mechanism mediated by a ligand-receptor pair in the regulation of gut hormone secretion, which can potentially be exploited to correct metabolic unbalance caused by overactivation of the gut-pancreas axis.
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Affiliation(s)
- Cong Tang
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Iwona Ksiazek
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Noemie Siccardi
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Berangere Gapp
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Delphine Weber
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | | | - Valerie Beck
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Matthias Reist
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Laurent Gaudet
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Nathalie Stuber
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | | | - Xiaohong Mao
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts
| | | | - Walter Carbone
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Martin Beibel
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Guglielmo Roma
- Novartis Institutes for BioMedical Research, Basel, Switzerland
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24
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Shokrollahi M, Chen JH, Huizinga JD. Intraluminal prucalopride increases propulsive motor activities via luminal 5-HT 4 receptors in the rabbit colon. Neurogastroenterol Motil 2019; 31:e13598. [PMID: 31012538 DOI: 10.1111/nmo.13598] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 03/13/2019] [Accepted: 03/28/2019] [Indexed: 02/08/2023]
Abstract
BACKGROUND Activating luminal 5-HT4 receptors results in the release of 5-HT from enterochromaffin cells into the lamina propria to modulate colonic motility. Our aim was to evaluate characteristics of colonic motor patterns involved in the prokinetic effects of intraluminal prucalopride in the rabbit colon. METHODS Colonic motor patterns were studied ex vivo using simultaneous spatiotemporal diameter mapping and pressure sensing. KEY RESULTS Intraluminal prucalopride and intraluminal exogenous 5-HT strongly evoked or enhanced the colonic motor complex at all levels of excitation beginning with generation of clusters of fast propagating contractions (FPCs), then development of long-distance contractions (LDCs) within the clusters, and finally forceful LDCs as the highest level of excitation. Intraluminal prucalopride and intraluminal exogenous 5-HT stimulated propulsive motor activity in a dose-dependent and antagonist-sensitive manner by increasing the contraction amplitude, intraluminal pressure, frequency, velocity, and degree of propagation of the colonic motor complex. CONCLUSIONS AND INFERENCES Activating mucosal 5-HT4 receptors via intraluminal prucalopride or 5-HT increases propulsive motor activity in a graded manner; that is, depending on starting conditions, amplitudes or frequencies of an activity may increase or a new pattern may be initiated. Our data support further studies into delivering 5-HT4 receptor agonists via colon-targeted drug delivery systems and studies into the role of luminal 5-HT as an essential requirement for normal colon motor pattern generation.
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Affiliation(s)
- Mitra Shokrollahi
- Division of Gastroenterology, Department of Medicine, Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | - Ji-Hong Chen
- Division of Gastroenterology, Department of Medicine, Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | - Jan D Huizinga
- Division of Gastroenterology, Department of Medicine, Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
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25
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Yu Y, Villalobos-Hernandez EC, Pradhananga S, Baker CC, Keating C, Grundy D, Lomax AE, Reed DE. Deoxycholic acid activates colonic afferent nerves via 5-HT 3 receptor-dependent and -independent mechanisms. Am J Physiol Gastrointest Liver Physiol 2019; 317:G275-G284. [PMID: 31216174 DOI: 10.1152/ajpgi.00016.2019] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Increased bile acids in the colon can evoke increased epithelial secretion resulting in diarrhea, but little is known about whether colonic bile acids contribute to abdominal pain. This study aimed to investigate the mechanisms underlying activation of colonic extrinsic afferent nerves and their neuronal cell bodies by a major secondary bile acid, deoxycholic acid (DCA). All experiments were performed on male C57BL/6 mice. Afferent sensitivity was evaluated using in vitro extracellular recordings from mesenteric nerves in the proximal colon (innervated by vagal and spinal afferents) and distal colon (spinal afferents only). Neuronal excitability of cultured dorsal root ganglion (DRG) and nodose ganglion (NG) neurons was examined with perforated patch clamp. Colonic 5-HT release was assessed using ELISA, and 5-HT immunoreactive enterochromaffin (EC) cells were quantified. Intraluminal DCA increased afferent nerve firing rate concentration dependently in both proximal and distal colon. This DCA-elicited increase was significantly inhibited by a 5-HT3 antagonist in the proximal colon but not in the distal colon, which may be in part due to lower 5-HT immunoreactive EC cell density and lower 5-HT levels in the distal colon following DCA stimulation. DCA increased the excitability of DRG neurons, whereas it decreased the excitability of NG neurons. DCA potentiated mechanosensitivity of high-threshold spinal afferents independent of 5-HT release. Together, this study suggests that DCA can excite colonic afferents via direct and indirect mechanisms but the predominant mechanism may differ between vagal and spinal afferents. Furthermore, DCA increased mechanosensitivity of high-threshold spinal afferents and may be a mechanism of visceral hypersensitivity.NEW & NOTEWORTHY Deoxycholic acid (DCA) directly excites spinal afferents and, to a lesser extent, indirectly via mucosal 5-HT release. DCA potentiates mechanosensitivity of high-threshold spinal afferents independent of 5-HT release. DCA increases vagal afferent firing in proximal colon via 5-HT release but directly inhibits the excitability of their cell bodies.
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Affiliation(s)
- Yang Yu
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | | | - Sabindra Pradhananga
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Corey C Baker
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Christopher Keating
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - David Grundy
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Alan E Lomax
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - David E Reed
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
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26
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Hamzah HH, Keattch O, Yeoman MS, Covill D, Patel BA. Three-Dimensional-Printed Electrochemical Sensor for Simultaneous Dual Monitoring of Serotonin Overflow and Circular Muscle Contraction. Anal Chem 2019; 91:12014-12020. [DOI: 10.1021/acs.analchem.9b02958] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Treichel AJ, Farrugia G, Beyder A. The touchy business of gastrointestinal (GI) mechanosensitivity. Brain Res 2019; 1693:197-200. [PMID: 29903622 DOI: 10.1016/j.brainres.2018.02.039] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 02/06/2018] [Accepted: 02/24/2018] [Indexed: 12/26/2022]
Abstract
The gastrointestinal (GI) tract's normal function depends on its ability to propel, mix, and store contents in a highly coordinated fashion. An ability to sense mechanical forces is therefore fundamental to normal GI tract operation. There are several mechanosensory circuits distributed throughout the GI tract. These circuits rely on a range of proposed specialized and non-specialized mechanosensory cells that include epithelial enterochromaffin (EC) cells, both intrinsic and extrinsic sensory neurons, glia, interstitial cells of Cajal (ICC), and smooth muscle cells. While the anatomy of these circuits is established, the molecular mechanisms and functions are still poorly understood. In this review, we focus on the neuro-epithelial mechanosensory circuit in the gut, composed of epithelial EC cells and sensory neurons, both intrinsic and extrinsic. Intriguingly, this circuit closely resembles the light touch circuit in the skin that is composed of an epithelial Merkel cell and an afferent sensory neuron, suggesting that the basic building blocks may be retained in diverse mechanosensory systems. We compare the gross and molecular anatomy and physiology of these circuits and dissect the roles of GI neuro-epithelial mechanosensory, or "GI touch", circuitry in GI health and disease.
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Affiliation(s)
- Anthony J Treichel
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Department of Physiology & Biomedical Engineering, Mayo Clinic, 200 First Street SW, Rochester, MN, USA
| | - Gianrico Farrugia
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Department of Physiology & Biomedical Engineering, Mayo Clinic, 200 First Street SW, Rochester, MN, USA
| | - Arthur Beyder
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Department of Physiology & Biomedical Engineering, Mayo Clinic, 200 First Street SW, Rochester, MN, USA.
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What is the role of endogenous gut serotonin in the control of gastrointestinal motility? Pharmacol Res 2019; 140:50-55. [DOI: 10.1016/j.phrs.2018.06.017] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 06/17/2018] [Accepted: 06/18/2018] [Indexed: 12/26/2022]
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Alcaino C, Knutson KR, Treichel AJ, Yildiz G, Strege PR, Linden DR, Li JH, Leiter AB, Szurszewski JH, Farrugia G, Beyder A. A population of gut epithelial enterochromaffin cells is mechanosensitive and requires Piezo2 to convert force into serotonin release. Proc Natl Acad Sci U S A 2018; 115:E7632-E7641. [PMID: 30037999 PMCID: PMC6094143 DOI: 10.1073/pnas.1804938115] [Citation(s) in RCA: 154] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Enterochromaffin (EC) cells constitute the largest population of intestinal epithelial enteroendocrine (EE) cells. EC cells are proposed to be specialized mechanosensory cells that release serotonin in response to epithelial forces, and thereby regulate intestinal fluid secretion. However, it is unknown whether EE and EC cells are directly mechanosensitive, and if so, what the molecular mechanism of their mechanosensitivity is. Consequently, the role of EE and EC cells in gastrointestinal mechanobiology is unclear. Piezo2 mechanosensitive ion channels are important for some specialized epithelial mechanosensors, and they are expressed in mouse and human EC cells. Here, we use EC and EE cell lineage tracing in multiple mouse models to show that Piezo2 is expressed in a subset of murine EE and EC cells, and it is distributed near serotonin vesicles by superresolution microscopy. Mechanical stimulation of a subset of isolated EE cells leads to a rapid inward ionic current, which is diminished by Piezo2 knockdown and channel inhibitors. In these mechanosensitive EE cells force leads to Piezo2-dependent intracellular Ca2+ increase in isolated cells as well as in EE cells within intestinal organoids, and Piezo2-dependent mechanosensitive serotonin release in EC cells. Conditional knockout of intestinal epithelial Piezo2 results in a significant decrease in mechanically stimulated epithelial secretion. This study shows that a subset of primary EE and EC cells is mechanosensitive, uncovers Piezo2 as their primary mechanotransducer, defines the molecular mechanism of their mechanotransduction and mechanosensitive serotonin release, and establishes the role of epithelial Piezo2 mechanosensitive ion channels in regulation of intestinal physiology.
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Affiliation(s)
- Constanza Alcaino
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Mayo Clinic, Rochester, MN 55905
| | - Kaitlyn R Knutson
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Mayo Clinic, Rochester, MN 55905
| | - Anthony J Treichel
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Mayo Clinic, Rochester, MN 55905
| | - Gulcan Yildiz
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Mayo Clinic, Rochester, MN 55905
| | - Peter R Strege
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Mayo Clinic, Rochester, MN 55905
| | - David R Linden
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Mayo Clinic, Rochester, MN 55905
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN 55905
| | - Joyce H Li
- Division of Gastroenterology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655
| | - Andrew B Leiter
- Division of Gastroenterology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655
| | - Joseph H Szurszewski
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Mayo Clinic, Rochester, MN 55905
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN 55905
| | - Gianrico Farrugia
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Mayo Clinic, Rochester, MN 55905
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN 55905
| | - Arthur Beyder
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Mayo Clinic, Rochester, MN 55905;
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN 55905
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von Volkmann HL, Brønstad I, Gilja OH, R Tronstad R, Sangnes DA, Nortvedt R, Hausken T, Dimcevski G, Fiskerstrand T, Nylund K. Prolonged intestinal transit and diarrhea in patients with an activating GUCY2C mutation. PLoS One 2017; 12:e0185496. [PMID: 28957388 PMCID: PMC5619782 DOI: 10.1371/journal.pone.0185496] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Accepted: 09/13/2017] [Indexed: 12/21/2022] Open
Abstract
Introduction Increased intestinal hydration by activation of the epithelial enzyme linked receptor guanylate cyclase C (GC-C) is a pharmacological principle for treating constipation. Activating mutations in the GUCY2C gene encoding GC-C cause Familial GUCY2C diarrhea syndrome (FGDS) which has been diagnosed with severe dysmotility. Aim To investigate gut motility and hormones before and after a meal in FGDS patients and compare with healthy controls (HC). Subjects and methods Bristol stool chart and stool frequency was assessed. Before and after a meal occlusive and non-occlusive contractions were obtained using ultrasound. A wireless motility capsule (WMC) recorded gut transit time, pH, contractions and pressure. Plasma levels of selected gut hormones were measured at different time points. Results The FGDS patients had 4 (range 1–10) loose stools/day and prolonged total gut transit time compared to HC, 55.5 h vs 28.5 h, respectively,with significantly increased colon transit time. In FGDS patients, pH in duodenum, small bowel and colon was increased and the number of contractions and the intraluminal pressure were significantly decreased, measured by WMC. Ultrasound showed in small bowel increased number of non-occlusive contractions in the FGDS patients. Serotonin (5-HT) plasma levels in the HC peaked 30 min after the meal, while the FGDS patients had no response. Conclusion Despite having diarrhea, the FGDS patients have prolonged transit time through the gut compared to HC, particularly in colon. The reduced number of intestinal contractions and lack of 5-HT release after a meal in FGDS patients surprisingly resemble colonic motility disturbances seen in patients with constipation.
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Affiliation(s)
- Hilde L von Volkmann
- National Centre for Ultrasound in Gastroenterology, Haukeland University Hospital, Bergen, Norway.,Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Ingeborg Brønstad
- National Centre for Ultrasound in Gastroenterology, Haukeland University Hospital, Bergen, Norway.,Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Odd Helge Gilja
- National Centre for Ultrasound in Gastroenterology, Haukeland University Hospital, Bergen, Norway.,Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Rune R Tronstad
- Department of Pediatrics, Haukeland University Hospital, Bergen, Norway.,Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Dag Andre Sangnes
- National Centre for Ultrasound in Gastroenterology, Haukeland University Hospital, Bergen, Norway
| | - Ragnar Nortvedt
- National Centre for Ultrasound in Gastroenterology, Haukeland University Hospital, Bergen, Norway
| | - Trygve Hausken
- National Centre for Ultrasound in Gastroenterology, Haukeland University Hospital, Bergen, Norway.,Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Georg Dimcevski
- National Centre for Ultrasound in Gastroenterology, Haukeland University Hospital, Bergen, Norway.,Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Torunn Fiskerstrand
- Department of Clinical Science, University of Bergen, Bergen, Norway.,Centres for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
| | - Kim Nylund
- National Centre for Ultrasound in Gastroenterology, Haukeland University Hospital, Bergen, Norway
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Spencer NJ, Keating DJ. Is There a Role for Endogenous 5-HT in Gastrointestinal Motility? How Recent Studies Have Changed Our Understanding. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 891:113-22. [PMID: 27379639 DOI: 10.1007/978-3-319-27592-5_11] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Over the past few years, there have been dramatic changes in our understanding of the role of endogenous 5-hydroxytryptamine (5-HT) in the generation of gastrointestinal (GI) motility patterns in the small and large intestine. The idea that endogenous 5-HT played a major role in the generation of peristalsis in the small intestine was first proposed in the mid 1950s, after it was discovered that endogenous 5-HT could be released from the mucosa at a similar time that peristalsis occurred; and that exogenous 5-HT could potently stimulate peristalsis. The fact that exogenous 5-HT stimulated peristalsis and that there was a similarity in timing between the release of 5-HT from the mucosa and the onset of peristalsis led investigators to propose that release of endogenous 5-HT from the mucosa was causally related to the generation of peristalsis. In further support of this, other studies showed that selective 5-HT antagonists could inhibit or block peristalsis, and other motor patterns, such as the migrating motor complex. Taken together, based on these findings, some laboratories believed that endogenous 5-HT (synthesized in the gut wall) was an important mediator, or initiator, of different propulsive motor patterns in the lower GI tract. This notion changed dramatically in the past few years, however, after it was discovered that removal of the mucosa abolished all cyclical release of endogenous 5-HT, but did not block peristalsis, nor the cyclical migrating complex. Furthermore, other laboratories revealed that genetic deletion of the gene tryptophan hydroxylase 1 (TPH-1) (that synthesizes endogenous 5-HT in the mucosa) actually had no inhibitory effect on transit of intestinal contents in live animals. Then, perhaps one of the most startling of all observations was the discovery that selective 5-HT receptor antagonists actually have the same inhibitory effects on peristalsis and the migrating complex in segments of intestine that had been depleted of all endogenous 5-HT. Taken together, these recent findings have led to a major revision in our understanding of the functional role of endogenous 5-HT in the generation of propulsive motor patterns in the lower GI tract. This review will focus on how our understanding of endogenous 5-HT in the GI tract has changed substantially in recent times.
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Affiliation(s)
- Nick J Spencer
- Department of Human Physiology and Centre for Neuroscience, School of Medicine, Flinders University of South Australia, Adelaide, SA, Australia.
| | - Damien J Keating
- Department of Human Physiology and Centre for Neuroscience, School of Medicine, Flinders University of South Australia, Adelaide, SA, Australia
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Patel BA, Fidalgo S, Wang C, Parmar L, Mandona K, Panossian A, Flint MS, Ranson RN, Saffrey MJ, Yeoman MS. The TNF-α antagonist etanercept reverses age-related decreases in colonic SERT expression and faecal output in mice. Sci Rep 2017; 7:42754. [PMID: 28198447 DOI: 10.1038/srep42754] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 01/12/2017] [Indexed: 12/11/2022] Open
Abstract
Treatment for chronic constipation in older people is challenging and the condition has a major impact on quality of life. A lack of understanding about the causes of this condition has hampered the development of effective treatments. 5-HT is an important pro-kinetic agent in the colon. We examined whether alterations in colonic 5-HT signalling underlie age-related changes in faecal output in mice and whether these changes were due to an increase in TNF-α. Components of the 5-HT signalling system (5-HT, 5-HIAA, SERT) and TNF-α expression were examined in the distal colon of 3, 12, 18 and 24-month old mice and faecal output and water content monitored under control conditions and following the administration of etanercept (TNF-α inhibitor; 1 mg Kg-1). Faecal output and water content were reduced in aged animals. Age increased mucosal 5-HT availability and TNF-α expression and decreased mucosal SERT expression and 5-HIAA. Etanercept treatment of old mice reversed these changes, suggesting that age-related changes in TNFα expression are an important regulator of mucosal 5-HT signalling and pellet output and water content in old mice. These data point to "anti-TNFα" drugs as potential treatments for age-related chronic constipation.
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Affiliation(s)
- Bhavik Anil Patel
- School of Pharmacy and Biomolecular Science, University of Brighton, Brighton, BN2 4GJ, UK
| | - Sara Fidalgo
- School of Pharmacy and Biomolecular Science, University of Brighton, Brighton, BN2 4GJ, UK
| | - Chunfang Wang
- Department of Life, Health and Chemical Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6AA, UK
| | - Leena Parmar
- School of Pharmacy and Biomolecular Science, University of Brighton, Brighton, BN2 4GJ, UK
| | - Kasonde Mandona
- School of Pharmacy and Biomolecular Science, University of Brighton, Brighton, BN2 4GJ, UK
| | - Annabelle Panossian
- School of Pharmacy and Biomolecular Science, University of Brighton, Brighton, BN2 4GJ, UK
| | - Melanie S Flint
- School of Pharmacy and Biomolecular Science, University of Brighton, Brighton, BN2 4GJ, UK
| | - Richard N Ranson
- Department of Applied Sciences, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK
| | - M Jill Saffrey
- Department of Life, Health and Chemical Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6AA, UK
| | - Mark S Yeoman
- School of Pharmacy and Biomolecular Science, University of Brighton, Brighton, BN2 4GJ, UK
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Alcaino C, Farrugia G, Beyder A. Mechanosensitive Piezo Channels in the Gastrointestinal Tract. CURRENT TOPICS IN MEMBRANES 2017; 79:219-244. [PMID: 28728818 PMCID: PMC5606247 DOI: 10.1016/bs.ctm.2016.11.003] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Sensation of mechanical forces is critical for normal function of the gastrointestinal (GI) tract and abnormalities in mechanosensation are linked to GI pathologies. In the GI tract there are several mechanosensitive cell types-epithelial enterochromaffin cells, intrinsic and extrinsic enteric neurons, smooth muscle cells and interstitial cells of Cajal. These cells use mechanosensitive ion channels that respond to mechanical forces by altering transmembrane ionic currents in a process called mechanoelectrical coupling. Several mechanosensitive ionic conductances have been identified in the mechanosensory GI cells, ranging from mechanosensitive voltage-gated sodium and calcium channels to the mechanogated ion channels, such as the two-pore domain potassium channels K2P (TREK-1) and nonselective cation channels from the transient receptor potential family. The recently discovered Piezo channels are increasingly recognized as significant contributors to cellular mechanosensitivity. Piezo1 and Piezo2 are nonselective cationic ion channels that are directly activated by mechanical forces and have well-defined biophysical and pharmacologic properties. The role of Piezo channels in the GI epithelium is currently under investigation and their role in the smooth muscle syncytium and enteric neurons is still not known. In this review, we outline the current state of knowledge on mechanosensitive ion channels in the GI tract, with a focus on the known and potential functions of the Piezo channels.
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Affiliation(s)
- C Alcaino
- Mayo Clinic College of Medicine, Rochester, MN, United States
| | - G Farrugia
- Mayo Clinic College of Medicine, Rochester, MN, United States
| | - A Beyder
- Mayo Clinic College of Medicine, Rochester, MN, United States
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Topographic distribution of serotonin-immunoreactive urethral endocrine cells and their relationship with calcitonin gene-related peptide-immunoreactive nerves in male rats. Acta Histochem 2017; 119:78-83. [PMID: 27939448 DOI: 10.1016/j.acthis.2016.11.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 11/09/2016] [Accepted: 11/28/2016] [Indexed: 10/20/2022]
Abstract
We investigated the topographic distribution and morphology of serotonin (5-HT)-immunoreactive endocrine cells in the urethra of male rats, and focused on their relationship with peptidergic nerve fibers immunoreactive for calcitonin gene-related peptide (CGRP). Urethral endocrine cells immunoreactive for 5-HT were densely distributed in the epithelial layers of the prostatic part, but were sparsely distributed in the membranous and spongy parts of urethra. Distribution of urethral endocrine cells with 5-HT immunoreactivity in the prostatic part was restricted from the internal urethral orifice to the region of seminal colliculus. 5-HT-immunoreactive endocrine cells were also observed in the ductal epithelial layers of coagulating glands, prostatic glands, and seminal vesicles. 5-HT-immunoreactive endocrine cells were triangular or flask in shape and possessed an apical projection extending toward the urethral lumen, and basal or lateral protrusions intruding between other epithelial cells were also detected in some cells. Double immunolabeling for 5-HT and CGRP revealed that CGRP-immunoreactive nerve fibers attached to urethral endocrine cells with 5-HT immunoreactivity in the prostatic part. These results suggest that urethral endocrine cells may release 5-HT in response to luminal stimuli, and that these cells and CGRP-immunoreactive nerves may regulate each other by an axon reflex mechanism.
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Linan-Rico A, Ochoa-Cortes F, Beyder A, Soghomonyan S, Zuleta-Alarcon A, Coppola V, Christofi FL. Mechanosensory Signaling in Enterochromaffin Cells and 5-HT Release: Potential Implications for Gut Inflammation. Front Neurosci 2016; 10:564. [PMID: 28066160 PMCID: PMC5165017 DOI: 10.3389/fnins.2016.00564] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 11/22/2016] [Indexed: 12/12/2022] Open
Abstract
Enterochromaffin (EC) cells synthesize 95% of the body 5-HT and release 5-HT in response to mechanical or chemical stimulation. EC cell 5-HT has physiological effects on gut motility, secretion and visceral sensation. Abnormal regulation of 5-HT occurs in gastrointestinal disorders and Inflammatory Bowel Diseases (IBD) where 5-HT may represent a key player in the pathogenesis of intestinal inflammation. The focus of this review is on mechanism(s) involved in EC cell "mechanosensation" and critical gaps in our knowledge for future research. Much of our knowledge and concepts are from a human BON cell model of EC, although more recent work has included other cell lines, native EC cells from mouse and human and intact mucosa. EC cells are "mechanosensors" that respond to physical forces generated during peristaltic activity by translating the mechanical stimulus (MS) into an intracellular biochemical response leading to 5-HT and ATP release. The emerging picture of mechanosensation includes Piezo 2 channels, caveolin-rich microdomains, and tight regulation of 5-HT release by purines. The "purinergic hypothesis" is that MS releases purines to act in an autocrine/paracrine manner to activate excitatory (P2Y1, P2Y4, P2Y6, and A2A/A2B) or inhibitory (P2Y12, A1, and A3) receptors to regulate 5-HT release. MS activates a P2Y1/Gαq/PLC/IP3-IP3R/SERCA Ca2+signaling pathway, an A2A/A2B-Gs/AC/cAMP-PKA signaling pathway, an ATP-gated P2X3 channel, and an inhibitory P2Y12-Gi/o/AC-cAMP pathway. In human IBD, P2X3 is down regulated and A2B is up regulated in EC cells, but the pathophysiological consequences of abnormal mechanosensory or purinergic 5-HT signaling remain unknown. EC cell mechanosensation remains poorly understood.
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Affiliation(s)
- Andromeda Linan-Rico
- Department of Anesthesiology, Wexner Medical Center at Ohio State UniversityColumbus, OH, USA; CONACYT-Centro Universitario de Investigaciones Biomedicas, University of ColimaColima, Mexico
| | - Fernando Ochoa-Cortes
- Department of Anesthesiology, Wexner Medical Center at Ohio State University Columbus, OH, USA
| | - Arthur Beyder
- Enteric Neuroscience Program, Division of Gastroenterology and Hepatology, Department of Physiology and Biomedical Engineering, Mayo Clinic Rochester, MN, USA
| | - Suren Soghomonyan
- Department of Anesthesiology, Wexner Medical Center at Ohio State University Columbus, OH, USA
| | - Alix Zuleta-Alarcon
- Department of Anesthesiology, Wexner Medical Center at Ohio State University Columbus, OH, USA
| | - Vincenzo Coppola
- SBS-Cancer Biology and Genetics, Ohio State University Columbus, OH, USA
| | - Fievos L Christofi
- Department of Anesthesiology, Wexner Medical Center at Ohio State University Columbus, OH, USA
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36
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Martins P, Fakhry J, de Oliveira EC, Hunne B, Fothergill LJ, Ringuet M, Reis DD, Rehfeld JF, Callaghan B, Furness JB. Analysis of enteroendocrine cell populations in the human colon. Cell Tissue Res 2016; 367:161-168. [DOI: 10.1007/s00441-016-2530-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 10/18/2016] [Indexed: 12/17/2022]
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37
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Spencer NJ, Sia TC, Brookes SJ, Costa M, Keating DJ. CrossTalk opposing view: 5-HT is not necessary for peristalsis. J Physiol 2016; 593:3229-31. [PMID: 26228548 DOI: 10.1113/jp270183] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 05/06/2015] [Indexed: 01/12/2023] Open
Affiliation(s)
- Nick J Spencer
- Department of Human Physiology and Centre for Neuroscience, Flinders University of South Australia, Adelaide, Australia
| | - Tiong Cheng Sia
- Department of Human Physiology and Centre for Neuroscience, Flinders University of South Australia, Adelaide, Australia
| | - Simon J Brookes
- Department of Human Physiology and Centre for Neuroscience, Flinders University of South Australia, Adelaide, Australia
| | - Marcello Costa
- Department of Human Physiology and Centre for Neuroscience, Flinders University of South Australia, Adelaide, Australia
| | - Damien J Keating
- Department of Human Physiology and Centre for Neuroscience, Flinders University of South Australia, Adelaide, Australia
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Patel BA. Mucosal serotonin overflow is associated with colonic stretch rather than phasic contractions. Neurogastroenterol Motil 2016; 28:914-23. [PMID: 26891254 DOI: 10.1111/nmo.12791] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 01/08/2016] [Indexed: 12/22/2022]
Abstract
BACKGROUND Many studies have shown that mucosal serotonin (5-HT) is associated with motility, however, recently there have been some questions to the precise role of this transmitter. The majority of studies have focused on understanding the role of mucosal 5-HT on colonic migratory motor complexes, but very few studies have been carried out to understand how 5-HT release may be associated with other motility patterns. METHODS Using distal colon segments from C57BL/6J mice, mucosal 5-HT overflow was monitored using amperometry while applying tension in longitudinal or circular directions to stretch the tissue. KEY RESULTS Phasic and basal 5-HT levels were not associated with the strength of phasic contractions, while being altered using scopolamine and L-NNA. There was a significant increase in mucosal 5-HT with longitudinal and circular muscle stretch. A greater applied force was needed to activate 5-HT release in the circular muscle. In the longitudinal muscle, 5-HT levels increased with stretch until 3 mN, after which the levels returned back to baseline. This stretch-evoked 5-HT overflow was inhibited by transient receptor potential A1 (TRPA1) agonist, 30 μM ruthenium red in both circular and longitudinal muscle preparations. The decreased 5-HT overflow after 3 mN of tension was reversed using a 5-HT4 antagonist 100 nM GR113808. CONCLUSIONS & INFERENCES Our findings show a relationship between colonic stretch and mucosal 5-HT overflow, while no relationship is observed with phasic colonic contractions. Such findings provide more insight into the role of mucosal 5-HT in influencing the pattern of colonic motility to diversify fecal propulsion.
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Affiliation(s)
- B A Patel
- School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, UK
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39
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Thorn P, Zorec R, Rettig J, Keating DJ. Exocytosis in non-neuronal cells. J Neurochem 2016; 137:849-59. [PMID: 26938142 DOI: 10.1111/jnc.13602] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 02/02/2016] [Accepted: 03/01/2016] [Indexed: 12/18/2022]
Abstract
Exocytosis is the process by which stored neurotransmitters and hormones are released via the fusion of secretory vesicles with the plasma membrane. It is a dynamic, rapid and spatially restricted process involving multiple steps including vesicle trafficking, tethering, docking, priming and fusion. For many years great steps have been undertaken in our understanding of how exocytosis occurs in different cell types, with significant focus being placed on synaptic release and neurotransmission. However, this process of exocytosis is an essential component of cell signalling throughout the body and underpins a diverse array of essential physiological pathways. Many similarities exist between different cell types with regard to key aspects of the exocytosis pathway, such as the need for Ca(2+) to trigger it or the involvement of members of the N-ethyl maleimide-sensitive fusion protein attachment protein receptor protein families. However, it is also equally clear that non-neuronal cells have acquired highly specialized mechanisms to control the release of their own unique chemical messengers. This review will focus on several important non-neuronal cell types and discuss what we know about the mechanisms they use to control exocytosis and how their specialized output is relevant to the physiological role of each individual cell type. These include enteroendocrine cells, pancreatic β cells, astrocytes, lactotrophs and cytotoxic T lymphocytes. Non-neuronal cells have acquired highly specialized mechanisms to control the release of unique chemical messengers, such as polarised fusion of insulin granules in pancreatic β cells targeted towards the vasculature (top). This review discusses mechanisms used in several important non-neuronal cell types to control exocytosis, and the relevance of intermediate vesicle fusion pore states (bottom) and their specialized output to the physiological role of each cell type. These include enteroendocrine cells, pancreatic β cells, astrocytes, lactotrophs and cytotoxic T lymphocytes. This article is part of a mini review series on Chromaffin cells (ISCCB Meeting, 2015).
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Affiliation(s)
- Peter Thorn
- Charles Perkins Centre, John Hopkins Drive, The University of Sydney, Camperdown, NSW, Australia
| | - Robert Zorec
- Laboratory of Neuroendocrinology and Molecular Cell Physiology, Institute of Pathophysiology, University of Ljubljana, Faculty of Medicine, Ljubljana, Slovenia.,Celica Biomedical, Ljubljana, Slovenia
| | - Jens Rettig
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Damien J Keating
- Department of Human Physiology and Centre for Neuroscience, Flinders University, Adelaide, SA, Australia.,South Australian Health and Medical Research Institute (SAHMRI), Adelaide, Australia
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Electrochemical fecal pellet sensor for simultaneous real-time ex vivo detection of colonic serotonin signalling and motility. Sci Rep 2016; 6:23442. [PMID: 27000971 PMCID: PMC4802304 DOI: 10.1038/srep23442] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 03/07/2016] [Indexed: 12/21/2022] Open
Abstract
Various investigations have focused on understanding the relationship between mucosal serotonin (5-HT) and colonic motility, however contradictory studies have questioned the importance of this intestinal transmitter. Here we described the fabrication and use of a fecal pellet electrochemical sensor that can be used to simultaneously detect the release of luminal 5-HT and colonic motility. Fecal pellet sensor devices were fabricated using carbon nanotube composite electrodes that were housed in 3D printed components in order to generate a device that had shape and size that mimicked a natural fecal pellet. Devices were fabricated where varying regions of the pellet contained the electrode. Devices showed that they were stable and sensitive for ex vivo detection of 5-HT, and no differences in the fecal pellet velocity was observed when compared to natural fecal pellets. The onset of mucosal 5-HT was observed prior to the movement of the fecal pellet. The release of mucosal 5-HT occurred oral to the fecal pellet and was linked to the contraction of the bowel wall that drove pellet propulsion. Taken, together these findings provide new insights into the role of mucosal 5-HT and suggest that the transmitter acts as a key initiator of fecal pellet propulsion.
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Spencer NJ. Constitutively Active 5-HT Receptors: An Explanation of How 5-HT Antagonists Inhibit Gut Motility in Species Where 5-HT is Not an Enteric Neurotransmitter? Front Cell Neurosci 2015; 9:487. [PMID: 26732863 PMCID: PMC4683187 DOI: 10.3389/fncel.2015.00487] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 11/30/2015] [Indexed: 11/19/2022] Open
Abstract
Antagonists of 5-Hydroxytryptamine (5-HT) receptors are well known to inhibit gastrointestinal (GI)-motility and transit in a variety of mammals, including humans. Originally, these observations had been interpreted by many investigators (including us) as evidence that endogenous 5-HT plays a major role in GI motility. This seemed a logical assumption. However, the story changed dramatically after recent studies revealed that 5-HT antagonists still blocked major GI motility patterns (peristalsis and colonic migrating motor complexes) in segments of intestine depleted of all 5-HT. Then, these results were further supported by Dr. Gershons' laboratory, which showed that genetic deletion of all genes that synthesizes 5-HT had minor, or no inhibitory effects on GI transit in vivo. If 5-HT was essential for GI motility patterns and transit, then one would expect major disruptions in motility and transit when 5-HT synthesis was genetically ablated. This does not occur. The inhibitory effects of 5-HT antagonists on GI motility clearly occur independently of any 5-HT in the gut. Evidence now suggests that 5-HT antagonists act on 5-HT receptors in the gut which are constitutively active, and don't require 5-HT for their activation. This would explain a long-standing mystery of how 5-HT antagonists inhibit gut motility in species like mice, rats, and humans where 5-HT is not an enteric neurotransmitter. Studies are now increasingly demonstrating that the presence of a neurochemical in enteric neurons does not mean they function as neurotransmitters. Caution should be exercised when interpreting any inhibitory effects of 5-HT antagonists on GI motility.
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Affiliation(s)
- Nick J Spencer
- Department of Human Physiology and Centre for Neuroscience, Flinders University of South Australia Adelaide, SA, Australia
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Zhu X, Liu Z, Qu H, Niu W, Gao L, Wang Y, Zhang A, Bai L. The effect and mechanism of electroacupuncture at LI11 and ST37 on constipation in a rat model. Acupunct Med 2015; 34:194-200. [PMID: 26561562 PMCID: PMC4941155 DOI: 10.1136/acupmed-2015-010897] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/11/2015] [Indexed: 01/03/2023]
Abstract
Background Electroacupuncture (EA) is used clinically for the treatment of constipation. Serotonin (5-hydroxytryptamine, 5-HT) plays an important role in colonic motility; however it is unknown whether alterations in colonic 5-HT are associated with EA. In this study, the effect and mechanism of EA at acupuncture points LI11 and ST37 were examined using a cold saline-induced rat model of constipation. Methods A rat constipation model was induced by cold saline gavage in 24 Sprague-Dawley rats. A further six rats were included as a Control group. The constipated rats were divided into four groups (n=6 each): a Constipation group that remained untreated; a Constipation+LI11 group that received EA at LI11; a Constipation+ST37 groups that received EA at ST37; and a Constipation+LI11+ST37 group that received EA at both LI11 and ST37. After EA treatment, faecal water content, defaecation frequency, and gastrointestinal (GI) transit were measured, as well as the expression of tryptophan hydroxylase (TPH) in colonic tissues (by Western blot analysis) and 5-HT in both faeces and colonic tissues (by ELISA). Results All three EA-treated groups demonstrated significant improvements in faecal water content, defaecation frequency and GI transit (p<0.05). In addition, TPH and 5-HT expression were both increased by EA at LI11 and/or ST37 (p<0.05). There were no significant differences between the three EA groups for any outcomes. Conclusions EA at LI11 and/or ST37 had a positive effect on objective markers of constipation in a rat model. In addition, EA increased 5-HT and TPH in the colonic tissues.
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Affiliation(s)
- Xianwei Zhu
- Innovation Research Centre of Acupuncture combined with Medicine, Shaanxi University of Chinese Medicine, Xi'an-Xianyang New Ecomic Zone, Shaanxi Province, China
| | - Zhibin Liu
- Innovation Research Centre of Acupuncture combined with Medicine, Shaanxi University of Chinese Medicine, Xi'an-Xianyang New Ecomic Zone, Shaanxi Province, China Department of Acupuncture and Moxibustion, Shaanxi University of Chinese Medicine, Xi'an-Xianyang New Ecomic Zone, Shaanxi Province, China
| | - Hongyan Qu
- Department of Acupuncture and Moxibustion, Shaanxi University of Chinese Medicine, Xi'an-Xianyang New Ecomic Zone, Shaanxi Province, China
| | - Wenmin Niu
- Innovation Research Centre of Acupuncture combined with Medicine, Shaanxi University of Chinese Medicine, Xi'an-Xianyang New Ecomic Zone, Shaanxi Province, China Department of Acupuncture and Moxibustion, Shaanxi University of Chinese Medicine, Xi'an-Xianyang New Ecomic Zone, Shaanxi Province, China
| | - Li Gao
- Department of Acupuncture and Moxibustion, Shaanxi University of Chinese Medicine, Xi'an-Xianyang New Ecomic Zone, Shaanxi Province, China
| | - Yuan Wang
- Innovation Research Centre of Acupuncture combined with Medicine, Shaanxi University of Chinese Medicine, Xi'an-Xianyang New Ecomic Zone, Shaanxi Province, China
| | - Aimin Zhang
- Department of Urologic Surgery, Affiliated Hospital of Shaanxi University of Chinese Medicine, Xi'an-Xianyang New Ecomic Zone, Shaanxi Province, China
| | - Lu Bai
- Department of English, Shaanxi University of Chinese Medicine, Xi'an-Xianyang New Ecomic Zone, Shaanxi Province, China
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Chambers JD, Thomas EA, Bornstein JC. Mathematical modelling of enteric neural motor patterns. Clin Exp Pharmacol Physiol 2014; 41:155-64. [PMID: 24471867 DOI: 10.1111/1440-1681.12209] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 11/21/2013] [Accepted: 11/26/2013] [Indexed: 01/07/2023]
Abstract
1. The enteric nervous system modulates intestinal behaviours, such as motor patterns and secretion. Although much is known about different types of neurons and simple reflexes in the intestine, it remains unclear how complex behaviours are generated. 2. Mathematical modelling is an important tool for assisting the understanding of how the neurons and reflexes can be pieced together to generate intestinal behaviours. 3. Models have identified a functional role for slow excitatory post-synaptic potentials (EPSPs) by distinguishing between fast and slow EPSPs in the ascending excitation reflex. These models also discovered coordinated firing of similarly located neurons as emergent properties of feed-forward networks of interneurons in the intestine. A model of the recurrent network of intrinsic sensory neurons identified important control mechanisms to prevent uncontrolled firing due to positive feedback and that the interaction between these control mechanisms and slow EPSPs is necessary for the networks to encode ongoing sensory stimuli. This model also showed that such networks may mediate migrating motor complexes. 4. A network model of vasoactive intestinal peptide neurons in the submucosal plexus found this relatively sparse recurrent network could produce uncontrolled firing under conditions that appear to be related to cholera toxin-induced hypersecretion. 5. Abstract modelling of the intestinal fed-state motor patterns has identified how stationary contractions can arise from a polarized network. 6. These models have also helped predict and/or explained pharmacological evidence for two rhythm generators and the requirement of feedback from contractions in the circular muscle.
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Affiliation(s)
- Jordan D Chambers
- Department of Physiology, University of Melbourne, Victoria, Australia
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Mazet B. Gastrointestinal motility and its enteric actors in mechanosensitivity: past and present. Pflugers Arch 2014; 467:191-200. [PMID: 25366494 DOI: 10.1007/s00424-014-1635-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Revised: 10/14/2014] [Accepted: 10/19/2014] [Indexed: 12/14/2022]
Abstract
Coordinated contractions of the smooth muscle layers of the gastrointestinal (GI) tract are required to produce motor patterns that ensure normal GI motility. The crucial role of the enteric nervous system (ENS), the intrinsic ganglionated network located within the GI wall, has long been recognized in the generation of the main motor patterns. However, devising an appropriate motility requires the integration of informations emanating from the lumen of the GI tract. As already found more than half a century ago, the ability of the GI tract to respond to mechanical forces such as stretch is not restricted to neuronal mechanisms. Instead, mechanosensitivity is now recognized as a property of several non-neuronal cell types, the excitability of which is probably involved in shaping the motor patterns. This brief review gives an overview on how mechanosensitivity of different cell types in the GI tract has been established and, whenever available, on what ionic conductances are involved in mechanotransduction and their potential impact on normal GI motility.
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Affiliation(s)
- Bruno Mazet
- Aix Marseille Université, CNRS, CRN2M UMR 7286, CS80011 Bd Pierre Dramard, 13344, Marseille Cedex 15, France,
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Gwynne RM, Clarke AJ, Furness JB, Bornstein JC. Both exogenous 5-HT and endogenous 5-HT, released by fluoxetine, enhance distension evoked propulsion in guinea-pig ileum in vitro. Front Neurosci 2014; 8:301. [PMID: 25285066 PMCID: PMC4168689 DOI: 10.3389/fnins.2014.00301] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 09/03/2014] [Indexed: 12/11/2022] Open
Abstract
The roles of 5-HT3 and 5-HT4 receptors in the modulation of intestinal propulsion by luminal application of 5-HT and augmentation of endogenous 5-HT effects were studied in segments of guinea-pig ileum in vitro. Persistent propulsive contractions evoked by saline distension were examined using a modified Trendelenburg method. When 5-HT (30 nM), fluoxetine (selective serotonin reuptake inhibitor; 1 nM), 2-methyl-5-HT (5-HT3 receptor agonist; 1 mM), or RS 67506 (5-HT4 receptor agonist, 1 μM) was infused into the lumen, the pressure needed to initiate persistent propulsive activity fell significantly. A specific 5-HT4 receptor antagonist, SB 207266 (10 nM in lumen), abolished the effects of 5-HT, fluoxetine, and RS 67506, but not those of 2-methyl-5-HT. Granisetron (5-HT3 receptor antagonist; 1 μM in lumen) abolished the effect of 5-HT, fluoxetine, RS 67506, and 2-methyl-5-HT. The NK3 receptor antagonist SR 142801 (100 nM in lumen) blocked the effects of 5-HT, fluoxetine, and 2-methyl-5-HT. SB 207266, granisetron, and SR 142801 had no effect by themselves. Higher concentrations of fluoxetine (100 and 300 nM) and RS 67506 (3 and 10 μM) had no effect on the distension threshold for propulsive contractions. These results indicate that luminal application of exogenous 5-HT, or increased release of endogenous mucosal 5-HT above basal levels, acts to lower the threshold for propulsive contractions in the guinea-pig ileum via activation of 5-HT3 and 5-HT4 receptors and the release of tachykinins. The results further indicate that basal release of 5-HT is insufficient to alter the threshold for propulsive motor activity.
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Affiliation(s)
- Rachel M Gwynne
- Department of Physiology, University of Melbourne Parkville, VIC, Australia
| | - Amanda J Clarke
- Department of Physiology, University of Melbourne Parkville, VIC, Australia
| | - John B Furness
- Departments of Anatomy and Cell Biology, University of Melbourne Parkville, VIC, Australia
| | - Joel C Bornstein
- Department of Physiology, University of Melbourne Parkville, VIC, Australia
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Yulia Z, Diana N, Anna S, Michael U. Brain as an endocrine source of circulating 5-hydroxytryptamine in ontogenesis in rats. Mol Cell Endocrinol 2014; 393:92-8. [PMID: 24952115 DOI: 10.1016/j.mce.2014.06.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 05/20/2014] [Accepted: 06/09/2014] [Indexed: 10/25/2022]
Abstract
This study was aimed to test the authors' hypothesis stating that the developing brain before the closure of the blood brain barrier (BBB) operates as an endocrine organ that secretes classical neurotransmitters and neuropeptides into the general circulation. 5-Hydroxytryptamine (5-HT) was selected as a marker of brain endocrine activity though it is also secreted by peripheral organs. 5-HT was detected in blood of rats in a biologically active concentration at any studied age, from the 21st embryonic day till the 30th postnatal day. The brain was proven to be a source of circulating 5-HT before the BBB closure by showing that the 5-HT concentration in blood decreased significantly after the inhibition of 5-HT synthesis in the brain of neonates. The 5-HT concentration in blood was not diminished after the BBB closure, apparently due to compensatory increase of 5-HT secretion by peripheral sources. Thus, brain-derived 5-HT is delivered to the general circulation before the BBB closure being potentially capable of providing endocrine regulation of target organs.
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Affiliation(s)
- Zubova Yulia
- Laboratory of Neural and Neuroendocrine Regulations, Institute of Developmental Biology, Russian Academy of Sciences, 26 Vavilov str., 119334 Moscow, Russia
| | - Nasyrova Diana
- Laboratory of Neural and Neuroendocrine Regulations, Institute of Developmental Biology, Russian Academy of Sciences, 26 Vavilov str., 119334 Moscow, Russia
| | - Sapronova Anna
- Laboratory of Neural and Neuroendocrine Regulations, Institute of Developmental Biology, Russian Academy of Sciences, 26 Vavilov str., 119334 Moscow, Russia
| | - Ugrumov Michael
- Laboratory of Neural and Neuroendocrine Regulations, Institute of Developmental Biology, Russian Academy of Sciences, 26 Vavilov str., 119334 Moscow, Russia.
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Fagan-Murphy A, Patel BA. Compressed multiwall carbon nanotube composite electrodes provide enhanced electroanalytical performance for determination of serotonin. Electrochim Acta 2014. [DOI: 10.1016/j.electacta.2014.06.050] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Di Carlo G, Trani A, Zane D, Ingo GM, Pasquali M, Dell'Era A, Curulli A. Influence of Different Biological Environments on Serotonin (5-HT) Electrochemical Behavior at Gold Screen Printed Electrodes. ELECTROANAL 2014. [DOI: 10.1002/elan.201400051] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Perez-Burgos A, Mao YK, Bienenstock J, Kunze WA. The gut-brain axis rewired: adding a functional vagal nicotinic "sensory synapse". FASEB J 2014; 28:3064-74. [PMID: 24719355 DOI: 10.1096/fj.13-245282] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
It is generally accepted that intestinal sensory vagal fibers are primary afferent, responding nonsynaptically to luminal stimuli. The gut also contains intrinsic primary afferent neurons (IPANs) that respond to luminal stimuli. A psychoactive Lactobacillus rhamnosus (JB-1) that affects brain function excites both vagal fibers and IPANs. We wondered whether, contrary to its primary afferent designation, the sensory vagus response to JB-1 might depend on IPAN to vagal fiber synaptic transmission. We recorded ex vivo single- and multiunit afferent action potentials from mesenteric nerves supplying mouse jejunal segments. Intramural synaptic blockade with Ca(2+) channel blockers reduced constitutive or JB-1-evoked vagal sensory discharge. Firing of 60% of spontaneously active units was reduced by synaptic blockade. Synaptic or nicotinic receptor blockade reduced firing in 60% of vagal sensory units that were stimulated by luminal JB-1. In control experiments, increasing or decreasing IPAN excitability, respectively increased or decreased nerve firing that was abolished by synaptic blockade or vagotomy. We conclude that >50% of vagal afferents function as interneurons for stimulation by JB-1, receiving input from an intramural functional "sensory synapse." This was supported by myenteric plexus nicotinic receptor immunohistochemistry. These data offer a novel therapeutic target to modify pathological gut-brain axis activity.-Perez-Burgos, A., Mao, Y.-K., Bienenstock, J., Kunze, W. A. The gut-brain axis rewired: adding a functional vagal nicotinic "sensory synapse."
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Affiliation(s)
- Azucena Perez-Burgos
- McMaster Brain-Body Institute, St. Joseph's Healthcare, Hamilton, Ontario, Canada; and
| | - Yu-Kang Mao
- McMaster Brain-Body Institute, St. Joseph's Healthcare, Hamilton, Ontario, Canada; and
| | - John Bienenstock
- McMaster Brain-Body Institute, St. Joseph's Healthcare, Hamilton, Ontario, Canada; and Department of Medicine, Department of Pathology and Molecular Medicine, and
| | - Wolfgang A Kunze
- McMaster Brain-Body Institute, St. Joseph's Healthcare, Hamilton, Ontario, Canada; and Department of Psychiatry and Behavioral Neurosciences, McMaster University, Hamilton, Ontario, Canada
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50
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Wang K, Bertrand RL, Senadheera S, Polglaze KE, Murphy TV, Sandow SL, Liu L, Bornstein JC, Bertrand PP. Motility changes induced by intraluminal FeSO4 in guinea pig jejunum. Neurogastroenterol Motil 2014; 26:385-96. [PMID: 24330033 DOI: 10.1111/nmo.12276] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 11/14/2013] [Indexed: 12/21/2022]
Abstract
BACKGROUND Dietary iron supplementation is associated with gastrointestinal (GI) side effects including vomiting, nausea, and diarrhea. Although inorganic iron in high concentrations may be damaging to the intestinal mucosa, we hypothesize that there are physiological effects on the GI tract that occur at concentrations achieved by supplementation. Thus, our aim was to investigate the effect of intraluminal ferrous sulfate (FeSO4 ) on jejunal motility. METHODS Segments of guinea pig jejunum were cannulated and the intraluminal pressure recorded with a transducer, while movements were recorded with a video camera. Peristaltic threshold was the oral pressure that evoked four consecutive propulsive contractions. The nutrients decanoic acid (1 mM), l-phenylalanine (50 mM), or the micronutrient FeSO4 (1 mM) were infused intraluminally. We also tested the effect of FeSO4 on electrochemically detected serotonin (5-HT, 5-hydroxytryptamine) released from in vitro tissues, both at rest and following mechanical stimulation. KEY RESULTS The jejuna peristaltic threshold was significantly decreased by all three nutrients: FeSO4 : 31 ± 2-23 ± 3 mmH2 O; decanoic acid: 27 ± 2-14 ± 2 mmH2 O; and l-phenylalanine: 30 ± 3-14 ± 3mmH2 O. Of the three, only decanoic acid induced segmentation, while FeSO4 inhibited decanoic acid-induced segmentation. Resting 5-HT release was increased by FeSO4 (128% of control), but mechanically evoked 5-HT release was reduced (70% of control). CONCLUSIONS & INFERENCES These data suggest that some luminal effects of inorganic iron on jejunal motility could be mediated through a pathway involving altered release of 5-HT. A better understanding of the interaction between luminal iron and 5-HT containing enterochromaffin cells could improve iron supplementation strategies, thus reducing side effects.
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Affiliation(s)
- K Wang
- Department of Physiology, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
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