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Sharkey KA, Mawe GM. The enteric nervous system. Physiol Rev 2023; 103:1487-1564. [PMID: 36521049 PMCID: PMC9970663 DOI: 10.1152/physrev.00018.2022] [Citation(s) in RCA: 36] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 12/12/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022] Open
Abstract
Of all the organ systems in the body, the gastrointestinal tract is the most complicated in terms of the numbers of structures involved, each with different functions, and the numbers and types of signaling molecules utilized. The digestion of food and absorption of nutrients, electrolytes, and water occurs in a hostile luminal environment that contains a large and diverse microbiota. At the core of regulatory control of the digestive and defensive functions of the gastrointestinal tract is the enteric nervous system (ENS), a complex system of neurons and glia in the gut wall. In this review, we discuss 1) the intrinsic neural control of gut functions involved in digestion and 2) how the ENS interacts with the immune system, gut microbiota, and epithelium to maintain mucosal defense and barrier function. We highlight developments that have revolutionized our understanding of the physiology and pathophysiology of enteric neural control. These include a new understanding of the molecular architecture of the ENS, the organization and function of enteric motor circuits, and the roles of enteric glia. We explore the transduction of luminal stimuli by enteroendocrine cells, the regulation of intestinal barrier function by enteric neurons and glia, local immune control by the ENS, and the role of the gut microbiota in regulating the structure and function of the ENS. Multifunctional enteric neurons work together with enteric glial cells, macrophages, interstitial cells, and enteroendocrine cells integrating an array of signals to initiate outputs that are precisely regulated in space and time to control digestion and intestinal homeostasis.
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Affiliation(s)
- Keith A Sharkey
- Hotchkiss Brain Institute and Snyder Institute for Chronic Diseases, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Gary M Mawe
- Department of Neurological Sciences, Larner College of Medicine, University of Vermont, Burlington, Vermont
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Furness JB, Di Natale M, Hunne B, Oparija-Rogenmozere L, Ward SM, Sasse KC, Powley TL, Stebbing MJ, Jaffey D, Fothergill LJ. The identification of neuronal control pathways supplying effector tissues in the stomach. Cell Tissue Res 2020; 382:433-445. [PMID: 33156383 DOI: 10.1007/s00441-020-03294-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Accepted: 09/11/2020] [Indexed: 12/14/2022]
Abstract
The stomach acts as a buffer between the ingestion of food and its processing in the small intestine. It signals to the brain to modulate food intake and it in turn regulates the passage of a nutrient-rich fluid, containing partly digested food, into the duodenum. These processes need to be finely controlled, for example to restrict reflux into the esophagus and to transfer digesta to the duodenum at an appropriate rate. Thus, the efferent pathways that control gastric volume, gastric peristalsis and digestive juice production are critically important. We review these pathways with an emphasis on the identities of the final motor neurons and comparisons between species. The major types of motor neurons arising from gastric enteric ganglia are as follows: immunohistochemically distinguishable excitatory and inhibitory muscle motor neurons; four neuron types innervating mucosal effectors (parietal cells, chief cells, gastrin cells and somatostatin cells); and vasodilator neurons. Sympathetic efferent neurons innervate intramural arteries, myenteric ganglia and gastric muscle. Vagal efferent neurons with cell bodies in the brain stem do not directly innervate gastric effector tissues; they are pre-enteric neurons that innervate each type of gastric enteric motor neuron. The principal transmitters and co-transmitters of gastric motor neurons, as well as key immunohistochemical markers, are the same in rat, pig, human and other species.
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Affiliation(s)
- John B Furness
- Department of Anatomy & Neuroscience, University of Melbourne, VIC, 3010, Parkville, Australia. .,Florey Institute of Neuroscience and Mental Health, VIC, 3010, Parkville, Australia.
| | - Madeleine Di Natale
- Department of Anatomy & Neuroscience, University of Melbourne, VIC, 3010, Parkville, Australia.,Florey Institute of Neuroscience and Mental Health, VIC, 3010, Parkville, Australia
| | - Billie Hunne
- Department of Anatomy & Neuroscience, University of Melbourne, VIC, 3010, Parkville, Australia
| | | | - Sean M Ward
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, NV, Reno, USA
| | - Kent C Sasse
- Sasse Surgical Associates, and Renown Regional Medical Center, NV, Reno, USA
| | - Terry L Powley
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, USA
| | - Martin J Stebbing
- Department of Anatomy & Neuroscience, University of Melbourne, VIC, 3010, Parkville, Australia.,Florey Institute of Neuroscience and Mental Health, VIC, 3010, Parkville, Australia
| | - Deborah Jaffey
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, USA
| | - Linda J Fothergill
- Department of Anatomy & Neuroscience, University of Melbourne, VIC, 3010, Parkville, Australia.,Florey Institute of Neuroscience and Mental Health, VIC, 3010, Parkville, Australia
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Grider JR. Gastrin-releasing peptide is a modulatory neurotransmitter of the descending phase of the peristaltic reflex. Am J Physiol Gastrointest Liver Physiol 2004; 287:G1109-15. [PMID: 15297260 DOI: 10.1152/ajpgi.00080.2004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The physiological role of gastrin-releasing peptide (GRP) and of its cognate receptors in regulating the intestinal peristaltic reflex was examined in a three-compartment flat-sheet preparation of rat colon. Mucosal stimulation applied to the central compartment at high, but not low levels of intensity, induced GRP release in the caudad compartment where descending relaxation was measured, but not into the ascending compartment where ascending contraction was measured or into the central compartment where the stimuli were applied. The selective GRP (BB(2)) receptor antagonist, [D-Phe(6),des-Met(14)]bombesin(6-14), inhibited descending relaxation and VIP release in the caudad compartment induced by high but not by low levels of stimulation applied to the mucosa in the central compartment. The selective neuromedin B (BB(1)) receptor antagonist, BIM-23127, had no effect on descending relaxation or VIP release. Neither the BB(1) nor the BB(2) antagonist had any effect on ascending contraction or substance P release in the orad compartment. Consistent with the effects of the antagonists on the peristaltic reflex, the BB(2) antagonist but not the BB(1) antagonist decreased the velocity of propulsion of artificial fecal pellets through isolated segments of guinea pig distal colon. The results indicate that GRP is selectively released from myenteric neurons in descending pathways during the peristaltic reflex and that it acts via BB(2) receptors to augment the descending phase of the peristaltic reflex and propulsion.
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Affiliation(s)
- John R Grider
- Department of Physiology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA 23298, USA.
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Pimont S, Bruley Des Varannes S, Le Neel JC, Aubert P, Galmiche JP, Neunlist M. Neurochemical coding of myenteric neurones in the human gastric fundus. Neurogastroenterol Motil 2003; 15:655-62. [PMID: 14651601 DOI: 10.1046/j.1350-1925.2003.00442.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The major functions of the stomach are under the control of the enteric nervous system (ENS), but the neuronal circuits involved in this control are largely unknown in humans. Enteric neurones can be characterized by their neuromediator or marker content, i.e. by neurochemical coding. The purpose of this study was to characterize the presence and co-localization of neurotransmitters in myenteric neurones of the human gastric fundus. Choline acetyltransferase (ChAT), neurone-specific enolase (NSE), vasoactive intestinal polypeptide (VIP), nitric oxide synthase (NOS), substance P (SP) were detected by immunohistochemical methods in whole mounts of gastric fundus myenteric plexus (seven patients). Antibodies against ChAT and NOS labelled the majority of myenteric neurones identified by NSE (57.2 +/- 5.6% and 40.8 +/- 4.5%, respectively; mean +/- SD). The proportions of VIP- and SP-immunoreactive neurones were significantly smaller, constituting 19.6 +/- 6.9% and 16.0 +/- 3.7%, respectively. Co-localization studies revealed five major populations representing over 75% of the myenteric neurones: ChAT/-, 30.1 +/- 6.1%; NOS/-, 24.2 +/- 4.4%; ChAT/SP/-, 8.3 +/- 3.1%; NOS/VIP/-, 7.2 +/- 6.0%; ChAT/VIP/-, 4.9 +/- 2.6. Some similarities are apparent in the neurochemical coding of myenteric neurones in the stomach and intestine of humans, and between the stomach of humans and animals, but striking differences exist. The precise functional role of the neurochemically identified classes of neurones remains to be determined.
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Affiliation(s)
- S Pimont
- INSERM U 539, Place Alexis Ricordeau, Nantes, France CIC-INSERM, Place Alexis Ricordeau, Nantes, France.
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Abstract
This paper is the twenty-third installment of the annual review of research concerning the opiate system. It summarizes papers published during 2000 that studied the behavioral effects of the opiate peptides and antagonists, excluding the purely analgesic effects, although stress-induced analgesia is included. The specific topics covered this year include stress; tolerance and dependence; learning, memory, and reward; eating and drinking; alcohol and other drugs of abuse; sexual activity, pregnancy, and development; mental illness and mood; seizures and other neurological disorders; electrical-related activity; general activity and locomotion; gastrointestinal, renal, and hepatic function; cardiovascular responses; respiration and thermoregulation; and immunological responses.
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Affiliation(s)
- A L Vaccarino
- Department of Psychology, University of New Orleans, New Orleans, LA 70148, USA.
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