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Kumar Palepu MS, Dandekar MP. Remodeling of microbiota gut-brain axis using psychobiotics in depression. Eur J Pharmacol 2022; 931:175171. [PMID: 35926568 DOI: 10.1016/j.ejphar.2022.175171] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 07/14/2022] [Accepted: 07/21/2022] [Indexed: 12/11/2022]
Abstract
Depression is a multifaceted psychiatric disorder mainly orchestrated by dysfunction of neuroendocrine, neurochemical, immune, and metabolic systems. The interconnection of gut microbiota perturbation with the central nervous system disorders has been well documented in recent times. Indeed, alteration of commensal intestinal microflora is noted in several psychiatric disorders such as anxiety and depression, which are presumed to be routed through the enteric nervous system, autonomic nervous system, endocrine, and immune system. This review summarises the new mechanisms underlying the crosstalk between gut microbiota and brain involved in the management of depression. Depression-induced changes in the commensal intestinal microbiota are majorly linked with the disruption of gut integrity, hyperinflammation, and modulation of short-chain fatty acids, neurotransmitters, kynurenine metabolites, endocannabinoids, brain-derived neurotropic factors, hypothalamic-pituitary-adrenal axis, and gut peptides. The restoration of gut microbiota with prebiotics, probiotics, postbiotics, synbiotics, and fermented foods (psychobiotics) has gained a considerable attention for the management of depression. Recent evidence also propose the role of gut microbiota in the process of treatment-resistant depression. Thus, remodeling of the microbiota-gut-brain axis using psychobiotics appears to be a promising therapeutic approach for the reversal of psychiatric disorders, and it is imperative to decipher the underlying mechanisms for gut-brain crosstalk.
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Affiliation(s)
- Mani Surya Kumar Palepu
- Department of Pharmacology & Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Balanagar, Hyderabad, Telangana, India
| | - Manoj P Dandekar
- Department of Pharmacology & Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Balanagar, Hyderabad, Telangana, India.
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2
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Brown RM, Guerrero-Hreins E, Brown WA, le Roux CW, Sumithran P. Potential gut-brain mechanisms behind adverse mental health outcomes of bariatric surgery. Nat Rev Endocrinol 2021; 17:549-559. [PMID: 34262156 DOI: 10.1038/s41574-021-00520-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/03/2021] [Indexed: 02/06/2023]
Abstract
Bariatric surgery induces sustained weight loss and metabolic benefits via notable effects on the gut-brain axis that lead to alterations in the neuroendocrine regulation of appetite and glycaemia. However, in a subset of patients, bariatric surgery is associated with adverse effects on mental health, including increased risk of suicide or self-harm as well as the emergence of depression and substance use disorders. The contributing factors behind these adverse effects are not well understood. Accumulating evidence indicates that there are important links between gut-derived hormones, microbial and bile acid profiles, and disorders of mood and substance use, which warrant further exploration in the context of changes in gut-brain signalling after bariatric surgery. Understanding the basis of these adverse effects is essential in order to optimize the health and well-being of people undergoing treatment for obesity.
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Affiliation(s)
- Robyn M Brown
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
- Department of Biochemistry and Pharmacology, School of Biomedical Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Eva Guerrero-Hreins
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
- Department of Biochemistry and Pharmacology, School of Biomedical Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Wendy A Brown
- Department of Surgery, Central Clinical School, Monash University, Alfred Hospital, Melbourne, Victoria, Australia
| | - Carel W le Roux
- Diabetes Complications Research Centre, Conway Institute, School of Medicine and Medical Sciences, University College, Dublin, Ireland
| | - Priya Sumithran
- Department of Medicine (St Vincent's), University of Melbourne, Melbourne, Victoria, Australia.
- Department of Endocrinology, Austin Health, Melbourne, Victoria, Australia.
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3
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Tolentino Bento da Silva M, Palheta-Junior RC, Silva CMS, Cavalcante AKM, Quetz JDS, Havt A, de Lima JBM, Mecawi ADS, de Castro M, Antunes-Rodrigues J, de Oliveira RB, Magalhães PJC, Aguiar Dos Santos A. Role of cholecystokinin and oxytocin in slower gastric emptying induced by physical exercise in rats. Physiol Behav 2021; 233:113355. [PMID: 33571545 DOI: 10.1016/j.physbeh.2021.113355] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 02/03/2021] [Accepted: 02/05/2021] [Indexed: 11/23/2022]
Abstract
Vigorous exercise can induce gastrointestinal disorders such decreased gastric emptying pace, while low-intensity exercise can accelerate gastric motility. However, the mechanisms of these effects are still unknown. We investigated the possible neurohumoral mechanisms involved in these phenomena. In sedentary (Sed) and acute exercise (Ex) groups of rats, we assessed the activation of c-Fos in NTS and DVMN and the plasma levels of CCK and OXT. Separate groups received pretreatment with the oxytocin antagonist atosiban (AT), the cholecystokinin antagonist devazepide (DVZ), or the TRPV1 receptor inhibitor capsazepine (CAPZ). AT, DVZ and CAPZ treatments prevented (p<0.05) slower gastric emptying induced by acute exercise. The gene expression of OXT decreased (P<0.05) while that of CCK increased (P<0.05) in the gastric fundus and pylorus of the Ex group, while the plasma levels of OXT rose (p<0.05) and of CCK declined (p<5.05). We also observed activation (p<0.05) of c-Fos-sensitive neurons in the NTS and DVMN of exercised rats. In conclusion, acute exercise slowed gastric emptying by the vagal afferent pathway, which involved activation of CCK1/OXT/TRPV1 sensitivity.
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Affiliation(s)
| | | | - Camila Meirelles Souza Silva
- Department of Physiology and Pharmacology, School of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
| | | | - Josiane da Silva Quetz
- Department of Physiology and Pharmacology, School of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
| | - Alexandre Havt
- Department of Physiology and Pharmacology, School of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
| | | | - André de Souza Mecawi
- Department of Biophisics, Palista School of Medicine, Federal University of São Paulo, São Paulo, SP, Brazil
| | - Margaret de Castro
- School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - José Antunes-Rodrigues
- School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | | | - Pedro Jorge Caldas Magalhães
- Department of Physiology and Pharmacology, School of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
| | - Armenio Aguiar Dos Santos
- Department of Physiology and Pharmacology, School of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
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4
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Klockars A, Levine AS, Head MA, Perez-Leighton CE, Kotz CM, Olszewski PK. Impact of Gut and Metabolic Hormones on Feeding Reward. Compr Physiol 2021; 11:1425-1447. [PMID: 33577129 DOI: 10.1002/cphy.c190042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Ingestion of food activates a cascade of endocrine responses (thereby reflecting a contemporaneous feeding status) that include the release of hormones from the gastrointestinal (GI) tract, such as cholecystokinin (CCK), glucagonlike peptide YY (PYY), peptide PP, and oleoylethanolamide, as well as suppression of ghrelin secretion. The pancreas and adipose tissue, on the other hand, release hormones that serve as a measure of the current metabolic state or the long-term energy stores, that is, insulin, leptin, and adiponectin. It is well known and intuitively understandable that these hormones target either directly (by crossing the blood-brain barrier) or indirectly (e.g., via vagal input) the "homeostatic" brainstem-hypothalamic pathways involved in the regulation of appetite. The current article focuses on yet another target of the metabolic and GI hormones that is critical in inducing changes in food intake, namely, the reward system. We discuss the physiological basis of this functional interaction, its importance in the control of appetite, and the impact that disruption of this crosstalk has on energy intake in select physiological and pathophysiological states. We conclude that metabolic and GI hormones have a capacity to strengthen or weaken a response of the reward system to a given food, and thus, they are fundamental in ensuring that feeding reward is plastic and dependent on the energy status of the organism. © 2021 American Physiological Society. Compr Physiol 11:1425-1447, 2021.
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Affiliation(s)
- Anica Klockars
- Faculty of Science and Engineering, University of Waikato, Hamilton, New Zealand
| | - Allen S Levine
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, Minnesota, USA
| | - Mitchell A Head
- Faculty of Science and Engineering, University of Waikato, Hamilton, New Zealand
| | | | - Catherine M Kotz
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, Minnesota, USA.,Department of Integrative Biology and Physiology, Medical School, University of Minnesota, Minneapolis, Minnesota, USA
| | - Pawel K Olszewski
- Faculty of Science and Engineering, University of Waikato, Hamilton, New Zealand.,Department of Food Science and Nutrition, University of Minnesota, St. Paul, Minnesota, USA.,Department of Integrative Biology and Physiology, Medical School, University of Minnesota, Minneapolis, Minnesota, USA
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López-Taboada I, González-Pardo H, Conejo NM. Western Diet: Implications for Brain Function and Behavior. Front Psychol 2020; 11:564413. [PMID: 33329193 PMCID: PMC7719696 DOI: 10.3389/fpsyg.2020.564413] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 10/02/2020] [Indexed: 12/12/2022] Open
Abstract
The Western diet (WD) pattern characterized by high daily intake of saturated fats and refined carbohydrates often leads to obesity and overweight, and it has been linked to cognitive impairment and emotional disorders in both animal models and humans. This dietary pattern alters the composition of gut microbiota, influencing brain function by different mechanisms involving the gut-brain axis. In addition, long-term exposure to highly palatable foods typical of WD could induce addictive-like eating behaviors and hypothalamic-pituitary-adrenal (HPA) axis dysregulation associated with chronic stress, anxiety, and depression. In turn, chronic stress modulates eating behavior, and it could have detrimental effects on different brain regions such as the hippocampus, hypothalamus, amygdala, and several cortical regions. Moreover, obesity and overweight induce neuroinflammation, causing neuronal dysfunction. In this review, we summarize the current scientific evidence about the mechanisms and factors relating WD consumption with altered brain function and behavior. Possible therapeutic interventions and limitations are also discussed, aiming to tackle and prevent this current pandemic.
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Affiliation(s)
| | | | - Nélida María Conejo
- Laboratory of Neuroscience, Department of Psychology, Instituto de Neurociencias del Principado de Asturias (INEUROPA), University of Oviedo, Oviedo, Spain
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6
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Yu Y, Yang W, Li Y, Cong Y. Enteroendocrine Cells: Sensing Gut Microbiota and Regulating Inflammatory Bowel Diseases. Inflamm Bowel Dis 2020; 26:11-20. [PMID: 31560044 PMCID: PMC7539793 DOI: 10.1093/ibd/izz217] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Indexed: 12/12/2022]
Abstract
Host sensing in the gut microbiota has been crucial in the regulation of intestinal homeostasis. Although inflammatory bowel diseases (IBDs), multifactorial chronic inflammatory conditions of the gastrointestinal tract, have been associated with intestinal dysbiosis, the detailed interactions between host and gut microbiota are still not completely understood. Enteroendocrine cells (EECs) represent 1% of the intestinal epithelium. Accumulating evidence indicates that EECs are key sensors of gut microbiota and/or microbial metabolites. They can secrete cytokines and peptide hormones in response to microbiota, either in traditional endocrine regulation or by paracrine impact on proximal tissues and/or cells or via afferent nerve fibers. Enteroendocrine cells also play crucial roles in mucosal immunity, gut barrier function, visceral hyperalgesia, and gastrointestinal (GI) motility, thereby regulating several GI diseases, including IBD. In this review, we will focus on EECs in sensing microbiota, correlating enteroendocrine perturbations with IBD, and the underlying mechanisms.
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Affiliation(s)
- Yanbo Yu
- Department of Gastroenterology, Qilu Hospital, Shandong University, Jinan, P.R. China,Department of Microbiology and Immunology and Branch, Galveston, Texas, USA
| | - Wenjing Yang
- Department of Microbiology and Immunology and Branch, Galveston, Texas, USA
| | - Yanqing Li
- Department of Gastroenterology, Qilu Hospital, Shandong University, Jinan, P.R. China
| | - Yingzi Cong
- Department of Microbiology and Immunology and Branch, Galveston, Texas, USA,Department of Pathology, University of Texas Medical Branch, Galveston, Texas, USA,Address correspondence to: Yingzi Cong, PhD, Department of Microbiology and Immunology, University of Texas Medical Branch, 4.142C Medical Research Building, 301 University Blvd, Galveston, TX 77555-1019 ()
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7
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Besecker EM, Blanke EN, Deiter GM, Holmes GM. Gastric vagal afferent neuropathy following experimental spinal cord injury. Exp Neurol 2019; 323:113092. [PMID: 31697943 DOI: 10.1016/j.expneurol.2019.113092] [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: 07/11/2019] [Revised: 09/11/2019] [Accepted: 10/23/2019] [Indexed: 01/01/2023]
Abstract
Dramatic impairment of gastrointestinal (GI) function accompanies high-thoracic spinal cord injury (T3-SCI). The vagus nerve contains mechano- and chemosensory fibers as well as the motor fibers necessary for the central nervous system (CNS) control of GI reflexes. Cell bodies for the vagal afferent fibers are located within the nodose gangla (NG) and the majority of vagal afferent axons are unmyelinated C fibers that are sensitive to capsaicin through activation of transient receptor potential vanilloid-1 (TRPV1) channels. Vagal afferent fibers also express receptors for GI hormones, including cholecystokinin (CCK). Previously, T3-SCI provokes a transient GI inflammatory response as well as a reduction of both gastric emptying and centrally-mediated vagal responses to GI peptides, including CCK. TRPV1 channels and CCK-A receptors (CCKar) expressed in vagal afferents are upregulated in models of visceral inflammation. The present study investigated whether T3-SCI attenuates peripheral vagal afferent sensitivity through plasticity of TRPV1 and CCK receptors. Vagal afferent response to graded mechanical stimulation of the stomach was significantly attenuated by T3-SCI at 3-day and 3-week recovery. Immunocytochemical labeling for CCKar and TRPV1 demonstrated expression on dissociated gastric-projecting NG neurons. Quantitative assessment of mRNA expression by qRT-PCR revealed significant elevation of CCKar and TRPV1 in the whole NG following T3-SCI in 3-day recovery, but levels returned to normal after 3-weeks. Three days after injury, systemic administration of CCK-8 s showed a significantly diminished gastric vagal afferent response in T3-SCI rats compared to control rats while systemic capsaicin infusion revealed a significant elevation of vagal response in T3-SCI vs control rats. These findings demonstrate that T3-SCI provokes peripheral remodeling and prolonged alterations in the response of vagal afferent fibers to the physiological signals associated with digestion.
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Affiliation(s)
- Emily M Besecker
- Department of Neural and Behavioral Sciences, Penn State University College of Medicine, Hershey, PA 17033, United States of America; Department of Health Sciences, Gettysburg College, Gettysburg, PA 17325, United States of America
| | - Emily N Blanke
- Department of Neural and Behavioral Sciences, Penn State University College of Medicine, Hershey, PA 17033, United States of America
| | - Gina M Deiter
- Department of Neural and Behavioral Sciences, Penn State University College of Medicine, Hershey, PA 17033, United States of America
| | - Gregory M Holmes
- Department of Neural and Behavioral Sciences, Penn State University College of Medicine, Hershey, PA 17033, United States of America.
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Powley TL, Jaffey DM, McAdams J, Baronowsky EA, Black D, Chesney L, Evans C, Phillips RJ. Vagal innervation of the stomach reassessed: brain-gut connectome uses smart terminals. Ann N Y Acad Sci 2019; 1454:14-30. [PMID: 31268562 DOI: 10.1111/nyas.14138] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 05/07/2019] [Accepted: 05/16/2019] [Indexed: 01/06/2023]
Abstract
Brain-gut neural communications have long been considered limited because of conspicuous numerical mismatches. The vagus, the parasympathetic nerve connecting brain and gut, contains thousands of axons, whereas the gastrointestinal (GI) tract contains millions of intrinsic neurons in local plexuses. The numerical paradox was initially recognized in terms of efferent projections, but the number of afferents, which comprise the majority (≈ 80%) of neurites in the vagus, is also relatively small. The present survey of recent morphological observations suggests that vagal terminals, and more generally autonomic and visceral afferent arbors in the stomach as well as throughout the gut, elaborate arbors that are extensive, regionally specialized, polymorphic, polytopic, and polymodal, commonly with multiplicities of receptors and binding sites-smart terminals. The morphological specializations and dynamic tuning of one-to-many efferent projections and many-to-one convergences of contacts onto afferents create a complex architecture capable of extensive peripheral integration in the brain-gut connectome and offset many of the disparities between axon and target numbers. Appreciating this complex architecture can help in the design of therapies for GI disorders.
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Affiliation(s)
- Terry L Powley
- Behavioral Neuroscience Area, Department of Psychological Sciences, Purdue University, West Lafayette, Indiana
| | - Deborah M Jaffey
- Behavioral Neuroscience Area, Department of Psychological Sciences, Purdue University, West Lafayette, Indiana
| | - Jennifer McAdams
- Behavioral Neuroscience Area, Department of Psychological Sciences, Purdue University, West Lafayette, Indiana
| | - Elizabeth A Baronowsky
- Behavioral Neuroscience Area, Department of Psychological Sciences, Purdue University, West Lafayette, Indiana
| | - Diana Black
- Behavioral Neuroscience Area, Department of Psychological Sciences, Purdue University, West Lafayette, Indiana
| | - Logan Chesney
- Behavioral Neuroscience Area, Department of Psychological Sciences, Purdue University, West Lafayette, Indiana
| | - Charlene Evans
- Behavioral Neuroscience Area, Department of Psychological Sciences, Purdue University, West Lafayette, Indiana
| | - Robert J Phillips
- Behavioral Neuroscience Area, Department of Psychological Sciences, Purdue University, West Lafayette, Indiana
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Davis RB, Ding S, Nielsen NR, Pawlak JB, Blakeney ES, Caron KM. Calcitonin-Receptor-Like Receptor Signaling Governs Intestinal Lymphatic Innervation and Lipid Uptake. ACS Pharmacol Transl Sci 2019; 2:114-121. [PMID: 32219216 DOI: 10.1021/acsptsci.8b00061] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Indexed: 02/06/2023]
Abstract
The absorption of dietary fat requires complex neuroendocrine-mediated regulation of chylomicron trafficking through enterocytes and intestinal lymphatic vessels. Calcitonin-receptor-like receptor (Calcrl) is a G protein-coupled receptor that can bind either a lymphangiogenic ligand adrenomedullin, with coreceptor RAMP2, or the neuropeptide CGRP, with coreceptor RAMP1. The extent to which this common GPCR controls lipid absorption via lymphatics or enteric innervation remains unclear. We used conditional and inducible genetic deletion of Calcrl in lymphatics to elucidate the pathophysiological consequences of this receptor pathway under conditions of high-fat diet. Inefficient absorption of dietary fat coupled with altered lymphatic endothelial junctions in Calcrl fl/fl /Prox1-CreER T2 mice results in excessive, transcellular lipid accumulation and abnormal enterocyte chylomicron processing and failure to gain weight. Interestingly, Calcrl fl/fl /Prox1-CreER T2 animals show reduced and disorganized mucosal and submucosal innervation. Consistently, mice with genetic loss of the CGRP coreceptor RAMP1 also displayed mucosal and submucosal innervation deficits, substantiating the CGRP-biased function of Calcrl in the neurolymphocrine axis. Thus, the common Calcrl receptor is a critical regulator of lipid absorption through its cell-specific functions in neurolymphocrine crosstalk.
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Affiliation(s)
- Reema B Davis
- Department of Cell Biology and Physiology, University of North Carolina Chapel Hill, 111 Mason Farm Road, 6312B Medical Biomolecular Research Building, CB#7545, Chapel Hill, North Carolina 27599-7545, United States
| | - Shengli Ding
- Department of Cell Biology and Physiology, University of North Carolina Chapel Hill, 111 Mason Farm Road, 6312B Medical Biomolecular Research Building, CB#7545, Chapel Hill, North Carolina 27599-7545, United States
| | - Natalie R Nielsen
- Department of Cell Biology and Physiology, University of North Carolina Chapel Hill, 111 Mason Farm Road, 6312B Medical Biomolecular Research Building, CB#7545, Chapel Hill, North Carolina 27599-7545, United States
| | - John B Pawlak
- Department of Cell Biology and Physiology, University of North Carolina Chapel Hill, 111 Mason Farm Road, 6312B Medical Biomolecular Research Building, CB#7545, Chapel Hill, North Carolina 27599-7545, United States
| | - Elizabeth S Blakeney
- Department of Cell Biology and Physiology, University of North Carolina Chapel Hill, 111 Mason Farm Road, 6312B Medical Biomolecular Research Building, CB#7545, Chapel Hill, North Carolina 27599-7545, United States
| | - Kathleen M Caron
- Department of Cell Biology and Physiology, University of North Carolina Chapel Hill, 111 Mason Farm Road, 6312B Medical Biomolecular Research Building, CB#7545, Chapel Hill, North Carolina 27599-7545, United States
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Mirza KB, Alenda A, Eftekhar A, Grossman N, Nikolic K, Bloom SR, Toumazou C. Influence of Cholecystokinin-8 on Compound Nerve Action Potentials from Ventral Gastric Vagus in Rats. Int J Neural Syst 2018; 28:1850006. [PMID: 29631504 DOI: 10.1142/s0129065718500065] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Vagus Nerve Stimulation (VNS) has shown great promise as a potential therapy for a number of conditions, such as epilepsy, depression and for Neurometabolic Therapies, especially for treating obesity. The objective of this study was to characterize the left ventral subdiaphragmatic gastric trunk of vagus nerve (SubDiaGVN) and to analyze the influence of intravenous injection of gut hormone cholecystokinin octapeptide (CCK-8) on compound nerve action potential (CNAP) observed on the same branch, with the aim of understanding the impact of hormones on VNS and incorporating the methods and results into closed loop implant design. METHODS The cervical region of the left vagus nerve (CerVN) of male Wistar rats was stimulated with electric current and the elicited CNAPs were recorded on the SubDiaGVN under four different conditions: Control (no injection), Saline, CCK1 (100[Formula: see text]pmol/kg) and CCK2 (1000[Formula: see text]pmol/kg) injections. RESULTS We identified the presence of A[Formula: see text], B, C1, C2, C3 and C4 fibers with their respective velocity ranges. Intravenous administration of CCK in vivo results in selective, statistically significant reduction of CNAP components originating from A and B fibers, but with no discernible effect on the C fibers in [Formula: see text] animals. The affected CNAP components exhibit statistically significant ([Formula: see text] and [Formula: see text]) higher normalized stimulation thresholds. CONCLUSION This approach of characterizing the vagus nerve can be used in closed loop systems to determine when to initiate VNS and also to tune the stimulation dose, which is patient-specific and changes over time.
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Affiliation(s)
- Khalid B Mirza
- * Institute of Biomedical Engineering, Department of Electrical and Electronic Engineering, Imperial College London, SW7 2AZ, UK
| | - Andrea Alenda
- * Institute of Biomedical Engineering, Department of Electrical and Electronic Engineering, Imperial College London, SW7 2AZ, UK
| | - Amir Eftekhar
- * Institute of Biomedical Engineering, Department of Electrical and Electronic Engineering, Imperial College London, SW7 2AZ, UK
| | - Nir Grossman
- * Institute of Biomedical Engineering, Department of Electrical and Electronic Engineering, Imperial College London, SW7 2AZ, UK
| | - Konstantin Nikolic
- * Institute of Biomedical Engineering, Department of Electrical and Electronic Engineering, Imperial College London, SW7 2AZ, UK
| | - Stephen R Bloom
- † Division of Diabetes, Endocrinology and Metabolism, Section of Endocrinology and Investigative Medicine, Imperial College London, W12 0NN, UK
| | - Christofer Toumazou
- * Institute of Biomedical Engineering, Department of Electrical and Electronic Engineering, Imperial College London, SW7 2AZ, UK
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11
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Lach G, Schellekens H, Dinan TG, Cryan JF. Anxiety, Depression, and the Microbiome: A Role for Gut Peptides. Neurotherapeutics 2018; 15:36-59. [PMID: 29134359 PMCID: PMC5794698 DOI: 10.1007/s13311-017-0585-0] [Citation(s) in RCA: 318] [Impact Index Per Article: 53.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The complex bidirectional communication between the gut and the brain is finely orchestrated by different systems, including the endocrine, immune, autonomic, and enteric nervous systems. Moreover, increasing evidence supports the role of the microbiome and microbiota-derived molecules in regulating such interactions; however, the mechanisms underpinning such effects are only beginning to be resolved. Microbiota-gut peptide interactions are poised to be of great significance in the regulation of gut-brain signaling. Given the emerging role of the gut-brain axis in a variety of brain disorders, such as anxiety and depression, it is important to understand the contribution of bidirectional interactions between peptide hormones released from the gut and intestinal bacteria in the context of this axis. Indeed, the gastrointestinal tract is the largest endocrine organ in mammals, secreting dozens of different signaling molecules, including peptides. Gut peptides in the systemic circulation can bind cognate receptors on immune cells and vagus nerve terminals thereby enabling indirect gut-brain communication. Gut peptide concentrations are not only modulated by enteric microbiota signals, but also vary according to the composition of the intestinal microbiota. In this review, we will discuss the gut microbiota as a regulator of anxiety and depression, and explore the role of gut-derived peptides as signaling molecules in microbiome-gut-brain communication. Here, we summarize the potential interactions of the microbiota with gut hormones and endocrine peptides, including neuropeptide Y, peptide YY, pancreatic polypeptide, cholecystokinin, glucagon-like peptide, corticotropin-releasing factor, oxytocin, and ghrelin in microbiome-to-brain signaling. Together, gut peptides are important regulators of microbiota-gut-brain signaling in health and stress-related psychiatric illnesses.
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Affiliation(s)
- Gilliard Lach
- APC Microbiome Institute, University College Cork, Cork, Ireland
| | - Harriet Schellekens
- APC Microbiome Institute, University College Cork, Cork, Ireland
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland
- Food for Health Ireland, University College Cork, Cork, Ireland
| | - Timothy G Dinan
- APC Microbiome Institute, University College Cork, Cork, Ireland
- Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland
| | - John F Cryan
- APC Microbiome Institute, University College Cork, Cork, Ireland.
- Food for Health Ireland, University College Cork, Cork, Ireland.
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Dinan TG, Cryan JF. Microbes, Immunity, and Behavior: Psychoneuroimmunology Meets the Microbiome. Neuropsychopharmacology 2017; 42:178-192. [PMID: 27319972 PMCID: PMC5143479 DOI: 10.1038/npp.2016.103] [Citation(s) in RCA: 135] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 05/26/2016] [Accepted: 06/13/2016] [Indexed: 02/07/2023]
Abstract
There is now a large volume of evidence to support the view that the immune system is a key communication pathway between the gut and brain, which plays an important role in stress-related psychopathologies and thus provides a potentially fruitful target for psychotropic intervention. The gut microbiota is a complex ecosystem with a diverse range of organisms and a sophisticated genomic structure. Bacteria within the gut are estimated to weigh in excess of 1 kg in the adult human and the microbes within not only produce antimicrobial peptides, short chain fatty acids, and vitamins, but also most of the common neurotransmitters found in the human brain. That the microbial content of the gut plays a key role in immune development is now beyond doubt. Early disruption of the host-microbe interplay can have lifelong consequences, not just in terms of intestinal function but in distal organs including the brain. It is clear that the immune system and nervous system are in continuous communication in order to maintain a state of homeostasis. Significant gaps in knowledge remain about the effect of the gut microbiota in coordinating the immune-nervous systems dialogue. However, studies using germ-free animals, infective models, prebiotics, probiotics, and antibiotics have increased our understanding of the interplay. Early life stress can have a lifelong impact on the microbial content of the intestine and permanently alter immune functioning. That early life stress can also impact adult psychopathology has long been appreciated in psychiatry. The challenge now is to fully decipher the molecular mechanisms that link the gut microbiota, immune, and central nervous systems in a network of communication that impacts behavior patterns and psychopathology, to eventually translate these findings to the human situation both in health and disease. Even at this juncture, there is evidence to pinpoint key sites of communication where gut microbial interventions either with drugs or diet or perhaps fecal microbiota transplantation may positively impact mental health.
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Affiliation(s)
- Timothy G Dinan
- APC Microbiome Institute, University College Cork, Cork, Ireland
- Department of Psychiatry & Neurobehavioural Sciences, University College Cork, Cork, Ireland
| | - John F Cryan
- APC Microbiome Institute, University College Cork, Cork, Ireland
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland
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Steinert RE, Feinle-Bisset C, Asarian L, Horowitz M, Beglinger C, Geary N. Ghrelin, CCK, GLP-1, and PYY(3-36): Secretory Controls and Physiological Roles in Eating and Glycemia in Health, Obesity, and After RYGB. Physiol Rev 2017; 97:411-463. [PMID: 28003328 PMCID: PMC6151490 DOI: 10.1152/physrev.00031.2014] [Citation(s) in RCA: 367] [Impact Index Per Article: 52.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The efficacy of Roux-en-Y gastric-bypass (RYGB) and other bariatric surgeries in the management of obesity and type 2 diabetes mellitus and novel developments in gastrointestinal (GI) endocrinology have renewed interest in the roles of GI hormones in the control of eating, meal-related glycemia, and obesity. Here we review the nutrient-sensing mechanisms that control the secretion of four of these hormones, ghrelin, cholecystokinin (CCK), glucagon-like peptide-1 (GLP-1), and peptide tyrosine tyrosine [PYY(3-36)], and their contributions to the controls of GI motor function, food intake, and meal-related increases in glycemia in healthy-weight and obese persons, as well as in RYGB patients. Their physiological roles as classical endocrine and as locally acting signals are discussed. Gastric emptying, the detection of specific digestive products by small intestinal enteroendocrine cells, and synergistic interactions among different GI loci all contribute to the secretion of ghrelin, CCK, GLP-1, and PYY(3-36). While CCK has been fully established as an endogenous endocrine control of eating in healthy-weight persons, the roles of all four hormones in eating in obese persons and following RYGB are uncertain. Similarly, only GLP-1 clearly contributes to the endocrine control of meal-related glycemia. It is likely that local signaling is involved in these hormones' actions, but methods to determine the physiological status of local signaling effects are lacking. Further research and fresh approaches are required to better understand ghrelin, CCK, GLP-1, and PYY(3-36) physiology; their roles in obesity and bariatric surgery; and their therapeutic potentials.
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Affiliation(s)
- Robert E Steinert
- University of Adelaide Discipline of Medicine and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide, Australia; DSM Nutritional Products, R&D Human Nutrition and Health, Basel, Switzerland; Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland; Department of Biomedicine and Division of Gastroenterology, University Hospital Basel, Basel, Switzerland; and Department of Psychiatry, Weill Medical College of Cornell University, New York, New York
| | - Christine Feinle-Bisset
- University of Adelaide Discipline of Medicine and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide, Australia; DSM Nutritional Products, R&D Human Nutrition and Health, Basel, Switzerland; Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland; Department of Biomedicine and Division of Gastroenterology, University Hospital Basel, Basel, Switzerland; and Department of Psychiatry, Weill Medical College of Cornell University, New York, New York
| | - Lori Asarian
- University of Adelaide Discipline of Medicine and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide, Australia; DSM Nutritional Products, R&D Human Nutrition and Health, Basel, Switzerland; Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland; Department of Biomedicine and Division of Gastroenterology, University Hospital Basel, Basel, Switzerland; and Department of Psychiatry, Weill Medical College of Cornell University, New York, New York
| | - Michael Horowitz
- University of Adelaide Discipline of Medicine and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide, Australia; DSM Nutritional Products, R&D Human Nutrition and Health, Basel, Switzerland; Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland; Department of Biomedicine and Division of Gastroenterology, University Hospital Basel, Basel, Switzerland; and Department of Psychiatry, Weill Medical College of Cornell University, New York, New York
| | - Christoph Beglinger
- University of Adelaide Discipline of Medicine and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide, Australia; DSM Nutritional Products, R&D Human Nutrition and Health, Basel, Switzerland; Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland; Department of Biomedicine and Division of Gastroenterology, University Hospital Basel, Basel, Switzerland; and Department of Psychiatry, Weill Medical College of Cornell University, New York, New York
| | - Nori Geary
- University of Adelaide Discipline of Medicine and National Health and Medical Research Council of Australia Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide, Australia; DSM Nutritional Products, R&D Human Nutrition and Health, Basel, Switzerland; Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland; Department of Biomedicine and Division of Gastroenterology, University Hospital Basel, Basel, Switzerland; and Department of Psychiatry, Weill Medical College of Cornell University, New York, New York
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El Aidy S, Stilling R, Dinan TG, Cryan JF. Microbiome to Brain: Unravelling the Multidirectional Axes of Communication. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 874:301-36. [PMID: 26589226 DOI: 10.1007/978-3-319-20215-0_15] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The gut microbiome plays a crucial role in host physiology. Disruption of its community structure and function can have wide-ranging effects making it critical to understand exactly how the interactive dialogue between the host and its microbiota is regulated to maintain homeostasis. An array of multidirectional signalling molecules is clearly involved in the host-microbiome communication. This interactive signalling not only impacts the gastrointestinal tract, where the majority of microbiota resides, but also extends to affect other host systems including the brain and liver as well as the microbiome itself. Understanding the mechanistic principles of this inter-kingdom signalling is fundamental to unravelling how our supraorganism function to maintain wellbeing, subsequently opening up new avenues for microbiome manipulation to favour desirable mental health outcome.
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Affiliation(s)
- Sahar El Aidy
- Microbial Physiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands
| | - Roman Stilling
- Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland.,Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland
| | - Timothy G Dinan
- Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland.,Department of Psychiatry, University College Cork, Cork, Ireland
| | - John F Cryan
- Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland. .,Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland.
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El Aidy S, Dinan TG, Cryan JF. Gut Microbiota: The Conductor in the Orchestra of Immune-Neuroendocrine Communication. Clin Ther 2015; 37:954-67. [PMID: 25846319 DOI: 10.1016/j.clinthera.2015.03.002] [Citation(s) in RCA: 147] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 02/23/2015] [Accepted: 03/04/2015] [Indexed: 01/01/2023]
Abstract
PURPOSE It is well established that mammals are so-called super-organisms that coexist with a complex microbiota. Growing evidence points to the delicacy of this host-microbe interplay and how disruptive interventions could have lifelong consequences. The goal of this article was to provide insights into the potential role of the gut microbiota in coordinating the immune-neuroendocrine cross-talk. METHODS Literature from a range of sources, including PubMed, Google Scholar, and MEDLINE, was searched to identify recent reports regarding the impact of the gut microbiota on the host immune and neuroendocrine systems in health and disease. FINDINGS The immune system and nervous system are in continuous communication to maintain a state of homeostasis. Significant gaps in knowledge remain regarding the effect of the gut microbiota in coordinating the immune-nervous systems dialogue. Recent evidence from experimental animal models found that stimulation of subsets of immune cells by the gut microbiota, and the subsequent cross-talk between the immune cells and enteric neurons, may have a major impact on the host in health and disease. IMPLICATIONS Data from rodent models, as well as from a few human studies, suggest that the gut microbiota may have a major role in coordinating the communication between the immune and neuroendocrine systems to develop and maintain homeostasis. However, the underlying mechanisms remain unclear. The challenge now is to fully decipher the molecular mechanisms that link the gut microbiota, the immune system, and the neuroendocrine system in a network of communication to eventually translate these findings to the human situation, both in health and disease.
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Affiliation(s)
- Sahar El Aidy
- Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland; Department of Industrial Biotechnology, Genetic Engineering and Biotechnology Research Institute, Sadat City University, Sadat City, Egypt
| | - Timothy G Dinan
- Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland; Department of Psychiatry, University College Cork, Cork, Ireland
| | - John F Cryan
- Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland.
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Bohórquez DV, Shahid RA, Erdmann A, Kreger AM, Wang Y, Calakos N, Wang F, Liddle RA. Neuroepithelial circuit formed by innervation of sensory enteroendocrine cells. J Clin Invest 2015; 125:782-6. [PMID: 25555217 DOI: 10.1172/jci78361] [Citation(s) in RCA: 311] [Impact Index Per Article: 34.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 11/20/2014] [Indexed: 12/20/2022] Open
Abstract
Satiety and other core physiological functions are modulated by sensory signals arising from the surface of the gut. Luminal nutrients and bacteria stimulate epithelial biosensors called enteroendocrine cells. Despite being electrically excitable, enteroendocrine cells are generally thought to communicate indirectly with nerves through hormone secretion and not through direct cell-nerve contact. However, we recently uncovered in intestinal enteroendocrine cells a cytoplasmic process that we named neuropod. Here, we determined that neuropods provide a direct connection between enteroendocrine cells and neurons innervating the small intestine and colon. Using cell-specific transgenic mice to study neural circuits, we found that enteroendocrine cells have the necessary elements for neurotransmission, including expression of genes that encode pre-, post-, and transsynaptic proteins. This neuroepithelial circuit was reconstituted in vitro by coculturing single enteroendocrine cells with sensory neurons. We used a monosynaptic rabies virus to define the circuit's functional connectivity in vivo and determined that delivery of this neurotropic virus into the colon lumen resulted in the infection of mucosal nerves through enteroendocrine cells. This neuroepithelial circuit can serve as both a sensory conduit for food and gut microbes to interact with the nervous system and a portal for viruses to enter the enteric and central nervous systems.
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Dockray GJ. Enteroendocrine cell signalling via the vagus nerve. Curr Opin Pharmacol 2013; 13:954-8. [DOI: 10.1016/j.coph.2013.09.007] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 08/28/2013] [Accepted: 09/04/2013] [Indexed: 02/06/2023]
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Wu T, Rayner CK, Young RL, Horowitz M. Gut motility and enteroendocrine secretion. Curr Opin Pharmacol 2013; 13:928-34. [PMID: 24060702 DOI: 10.1016/j.coph.2013.09.002] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 08/16/2013] [Accepted: 09/04/2013] [Indexed: 02/07/2023]
Abstract
The motility of the gastrointestinal (GI) tract is modulated by complex neural and hormonal networks; the latter include gut peptides released from enteroendocrine cells during both the interdigestive and postprandial periods. Conversely, it is increasingly recognised that GI motility is an important determinant of gut hormone secretion, in that the transit of luminal contents influences the degree of nutrient stimulation of enteroendocrine cells in different gut regions, as well as the overall length of gut exposed to nutrient. Of particular interest is the relationship between gallbladder emptying and enteroendocrine secretion. The inter-relationships between GI motility and enteroendocrine secretion are central to blood glucose homeostasis, where an understanding is fundamental to the development of novel strategies for the management of diabetes mellitus.
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Affiliation(s)
- Tongzhi Wu
- Discipline of Medicine, University of Adelaide, Royal Adelaide Hospital, Adelaide, South Australia, Australia; Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Australia
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Gamble J, Kenny S, Dockray GJ. Plasminogen activator inhibitor (PAI)-1 suppresses inhibition of gastric emptying by cholecystokinin (CCK) in mice. ACTA ACUST UNITED AC 2013; 185:9-13. [PMID: 23816469 PMCID: PMC3819999 DOI: 10.1016/j.regpep.2013.06.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 03/05/2013] [Accepted: 06/19/2013] [Indexed: 12/26/2022]
Abstract
The intestinal hormone cholecystokinin (CCK) delays gastric emptying and inhibits food intake by actions on vagal afferent neurons. Recent studies suggest plasminogen activator inhibitor (PAI)-1 suppresses the effect of CCK on food intake. In this study we asked whether PAI-1 also modulated CCK effects on gastric emptying. Five minute gastric emptying of liquid test meals was studied in conscious wild type mice (C57BL/6) and in transgenic mice over-expressing PAI-1 in gastric parietal cells (PAI-1H/Kβ mice), or null for PAI-1. The effects of exogenous PAI-1 and CCK8s on gastric emptying were studied after ip administration. Intragastric peptone delayed gastric emptying in C57BL/6 mice by a mechanism sensitive to the CCK-1 receptor antagonist lorglumide. Peptone did not delay gastric emptying in PAI-1-H/Kβ mice. Exogenous CCK delayed gastric emptying of a control test meal in C57BL/6 mice and this was attenuated by administration of PAI-1; exogenous CCK had no effect on emptying in PAI-1-H/Kβ mice. Prior administration of gastrin to increase gastric PAI-1 inhibited CCK-dependent effects on gastric emptying in C57BL/6 mice but not in PAI-1 null mice. Thus, both endogenous and exogenous PAI-1 inhibit the effects of CCK (whether exogenous or endogenous) on gastric emptying. The data are compatible with emerging evidence that gastric PAI-1 modulates vagal effects of CCK. Cholecystokinin (CCK) inhibits gastric emptying and food intake. PAI-1 inhibits effects of CCK on food intake. We hypothesised that PAI-1 also modulates gastric emptying. Both endogenous and exogenous PAI-1 attenuated the effect of CCK on gastric emptying. Gastric PAI-1 is therefore a modulator of CCK inhibition of gastric emptying.
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Affiliation(s)
- Joanne Gamble
- Physiological Laboratory, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
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Abstract
PURPOSE OF REVIEW Cholecystokinin (CCK) controls nutrient delivery to the small intestine by inhibiting food intake and gastric emptying. This review deals with recent work shedding new light on how and when. RECENT FINDINGS Intestinal I-cells release CCK in response to dietary lipid and protein through mechanisms involving the G-protein-coupled receptors GPR40 and calcium-sensing receptor. Vagal afferent neurons are a primary target of CCK and are now recognized as an important site of integration of peripheral signals regulating ingestion. In addition to regulating vagal afferent nerve discharge, CCK also controls the expression of receptors and peptide neurotransmitters by these neurons; these actions are potentiated by leptin and inhibited by ghrelin. The responses of vagal afferent neurons to CCK are attenuated in obesity. Studies of human central nervous system responses using functional magnetic resonance imaging indicate activation of brainstem, hypothalamus and motor cortex by ingested fatty acid that is inhibited by a CCK-1 receptor antagonist. CCK may also play a role in adaptive responses in pancreatic islets by maintaining β-cell mass and acting as an incretin in certain circumstances. SUMMARY CCK mediates inhibition of food intake in response to ingested lipid and protein; resistance to CCK occurs in obesity and may contribute to altered mechanisms regulating food intake.
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Affiliation(s)
- Graham J Dockray
- Physiological Laboratory, Institute of Translational Medicine, University of Liverpool, Liverpool, UK.
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Viard E, Rogers RC, Hermann GE. Systemic cholecystokinin amplifies vago-vagal reflex responses recorded in vagal motor neurones. J Physiol 2011; 590:631-46. [PMID: 22155934 DOI: 10.1113/jphysiol.2011.224477] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Cholecystokinin (CCK) is a potent regulator of visceral functions as a consequence of its actions on vago-vagal reflex circuit elements. This paper addresses three current controversies regarding the role of CCK to control gastric function via vago-vagal reflexes. Specifically: (a) whether CNS vs. peripheral (vagal afferent) receptors are dominant, (b) whether the long (58) vs. short (8) isoform is more potent and (c) whether nutritional status impacts the gain or even the direction of vago-vagal reflexes. Our in vivo recordings of physiologically identified gastric vagal motor neurones (gastric-DMN) involved in the gastric accommodation reflex (GAR) show unequivocally that: (a) receptors in the coeliac-portal circulation are more sensitive in amplifying gastric vagal reflexes; (b) in the periphery, CCK8 is more potent than CCK58; and (c) the nutritional status has a marginal effect on gastric reflex control. While the GAR reflex is more sensitive in the fasted rat, CCK amplifies this sensitivity. Thus, our results are in stark contrast to recent reports which have suggested that vago-vagal reflexes are inverted by the metabolic status of the animal and that this inversion could be mediated by CCK within the CNS.
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Affiliation(s)
- Edouard Viard
- Pennington Biomedical Research Centre, 6400 Perkins Rd, Baton Rouge, LA 70808, USA
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Browning KN, Wan S, Baptista V, Travagli RA. Vanilloid, purinergic, and CCK receptors activate glutamate release on single neurons of the nucleus tractus solitarius centralis. Am J Physiol Regul Integr Comp Physiol 2011; 301:R394-401. [PMID: 21543639 DOI: 10.1152/ajpregu.00054.2011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Baroreceptor inputs to nucleus of the tractus solitarius medialis (mNTS) neurons can be differentiated, among other features, by their response to vanilloid or purinergic agonists, active only on C- or A-fibers, respectively. A major aim of this study was to examine whether neurons of NTS centralis (cNTS), a subnucleus dominated by esophageal inputs, exhibit a similar dichotomy. Since it has been suggested that cholecystokinin (CCK), exerts its gastrointestinal (GI)-related effects via paracrine activation of vagal afferent C-fibers, we tested whether CCK-sensitive fibers impinging upon cNTS neurons are responsive to vanilloid but not purinergic agonists. Using whole cell patch-clamp recordings from cNTS, we recorded miniature excitatory postsynaptic currents (mEPSCs) to test the effects of the vanilloid agonist capsaicin, the purinergic agonist α,β-methylene-ATP (α,β-Met-ATP), and/or CCK-octapeptide (CCK-8s). α,β-Met-ATP, capsaicin; and CCK-8s increased EPSC frequency in 37, 71, and 46% of cNTS neurons, respectively. Approximately 30% of cNTS neurons were responsive to both CCK-8s and α,β-Met-ATP, to CCK-8s and capsaicin, or to α,β-Met-ATP and capsaicin, while 32% of neurons were responsive to all three agonists. All neurons responding to either α,β-Met-ATP or CCK-8s were also responsive to capsaicin. Perivagal capsaicin, which is supposed to induce a selective degeneration of C-fibers, decreased the number of cNTS neurons responding to capsaicin or CCK-8s but not those responding to α,β-Met-ATP. In summary, GI inputs to cNTS neurons cannot be distinguished on the basis of their selective responses to α,β-Met-ATP or capsaicin. Our data also indicate that CCK-8s increases glutamate release from purinergic and vanilloid responsive fibers impinging on cNTS neurons.
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Affiliation(s)
- Kirsteen N Browning
- Neural and Behavioral Sciences, Penn State College of Medicine, Hershey, Pennsylvania 17033-0850, USA
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Jahan-Mihan A, Luhovyy BL, El Khoury D, Anderson GH. Dietary proteins as determinants of metabolic and physiologic functions of the gastrointestinal tract. Nutrients 2011; 3:574-603. [PMID: 22254112 PMCID: PMC3257691 DOI: 10.3390/nu3050574] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Revised: 04/29/2011] [Accepted: 05/09/2011] [Indexed: 02/07/2023] Open
Abstract
Dietary proteins elicit a wide range of nutritional and biological functions. Beyond their nutritional role as the source of amino acids for protein synthesis, they are instrumental in the regulation of food intake, glucose and lipid metabolism, blood pressure, bone metabolism and immune function. The interaction of dietary proteins and their products of digestion with the regulatory functions of the gastrointestinal (GI) tract plays a dominant role in determining the physiological properties of proteins. The site of interaction is widespread, from the oral cavity to the colon. The characteristics of proteins that influence their interaction with the GI tract in a source-dependent manner include their physico-chemical properties, their amino acid composition and sequence, their bioactive peptides, their digestion kinetics and also the non-protein bioactive components conjugated with them. Within the GI tract, these products affect several regulatory functions by interacting with receptors releasing hormones, affecting stomach emptying and GI transport and absorption, transmitting neural signals to the brain, and modifying the microflora. This review discusses the interaction of dietary proteins during digestion and absorption with the physiological and metabolic functions of the GI tract, and illustrates the importance of this interaction in the regulation of amino acid, glucose, lipid metabolism, and food intake.
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Affiliation(s)
- Alireza Jahan-Mihan
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
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