1
|
Di Salvo C, D'Antongiovanni V, Benvenuti L, Fornai M, Valdiserra G, Natale G, Ryskalin L, Lucarini E, Mannelli LDC, Ghelardini C, Colucci R, Haskó G, Pellegrini C, Antonioli L. The pharmacological blockade of P2X4 receptor as a viable approach to manage visceral pain in a rat model of colitis. J Drug Target 2024; 32:953-963. [PMID: 38864378 DOI: 10.1080/1061186x.2024.2367563] [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: 01/21/2024] [Revised: 06/04/2024] [Accepted: 06/07/2024] [Indexed: 06/13/2024]
Abstract
Nowadays, the pharmacological management of visceral hypersensitivity associated with colitis is ineffective. In this context, targeting purinergic P2X4 receptor (P2X4R), which can modulate visceral pain transmission, could represent a promising therapeutic strategy. Herein, we tested the pain-relieving effect of two novel and selective P2X4R antagonists (NC-2600 and NP-1815-PX) in a murine model of DNBS-induced colitis and investigated the mechanisms underlying their effect. Tested drugs and dexamethasone (DEX) were administered orally, two days after colitis induction. Treatment with tested drugs and DEX improved tissue inflammatory parameters (body weight, spleen weight, macroscopic damage, TNF and IL-1β levels) in DNBS-rats. In addition, NC-2600 and NP-1815-PX attenuated visceral pain better than DEX and prevented the reduction of occludin expression. In in vitro studies, treatment of CaCo2 cells with supernatant from THP-1 cells, previously treated with LPS plus ATP, reduced the expression of tight junctions protein. By contrast, CaCo2 cells treated with supernatant from THP-1 cells, previously incubated with tested drugs, counteracted the reduction of tight junctions due to the inhibition of P2X4R/NLRP3/IL-1β axis. In conclusion, these results suggest that the direct and selective inhibition of P2X4R represents a viable approach for the management of visceral pain associated with colitis via NLRP3/IL-1β axis inhibition.
Collapse
Affiliation(s)
- Clelia Di Salvo
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | | | - Laura Benvenuti
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Matteo Fornai
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Giulia Valdiserra
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Gianfranco Natale
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Larisa Ryskalin
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Elena Lucarini
- Department of Neuroscience, Psychology, Drug Research and Child Health, Neurofarba, Pharmacology and Toxicology Section, University of Florence, Florence, Italy
| | - Lorenzo Di Cesare Mannelli
- Department of Neuroscience, Psychology, Drug Research and Child Health, Neurofarba, Pharmacology and Toxicology Section, University of Florence, Florence, Italy
| | - Carla Ghelardini
- Department of Neuroscience, Psychology, Drug Research and Child Health, Neurofarba, Pharmacology and Toxicology Section, University of Florence, Florence, Italy
| | - Rocchina Colucci
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padova, Italy
| | - György Haskó
- Department of Anesthesiology, Columbia University Irving Medical Center, New York, NY, USA
| | - Carolina Pellegrini
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Luca Antonioli
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| |
Collapse
|
2
|
Carbajal-García A, Reyes-García J, Díaz-Hernández V, Casas-Hernández MF, Flores-Murrieta FJ, Montaño LM. Testosterone Enhances K V Currents and Airway Smooth Muscle Relaxation Induced by ATP and UTP through P2Y 4 Receptors and Adenylyl Cyclase Pathway. Int J Mol Sci 2024; 25:4652. [PMID: 38731872 PMCID: PMC11083821 DOI: 10.3390/ijms25094652] [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: 02/29/2024] [Revised: 04/07/2024] [Accepted: 04/17/2024] [Indexed: 05/13/2024] Open
Abstract
Numerous studies suggest the involvement of adenosine-5'-triphosphate (ATP) and similar nucleotides in the pathophysiology of asthma. Androgens, such as testosterone (TES), are proposed to alleviate asthma symptoms in young men. ATP and uridine-5'-triphosphate (UTP) relax the airway smooth muscle (ASM) via purinergic P2Y2 and P2Y4 receptors and K+ channel opening. We previously demonstrated that TES increased the expression of voltage-dependent K+ (KV) channels in ASM. This study investigates how TES may potentiate ASM relaxation induced by ATP and UTP. Tracheal tissues treated with or without TES (control group) from young male guinea pigs were used. In organ baths, tracheas exposed to TES (40 nM for 48 h) showed enhanced ATP- and UTP-evoked relaxation. Tetraethylammonium, a K+ channel blocker, annulled this effect. Patch-clamp experiments in tracheal myocytes showed that TES also increased ATP- and UTP-induced K+ currents, and this effect was abolished with flutamide (an androgen receptor antagonist). KV channels were involved in this phenomenon, which was demonstrated by inhibition with 4-aminopyridine. RB2 (an antagonist of almost all P2Y receptors except for P2Y2), as well as N-ethylmaleimide and SQ 22,536 (inhibitors of G proteins and adenylyl cyclase, respectively), attenuated the enhancement of the K+ currents induced by TES. Immunofluorescence and immunohistochemistry studies revealed that TES did not modify the expression of P2Y4 receptors or COX-1 and COX-2, while we have demonstrated that this androgen augmented the expression of KV1.2 and KV1.5 channels in ASM. Thus, TES leads to the upregulation of P2Y4 signaling and KV channels in guinea pig ASM, enhancing ATP and UTP relaxation responses, which likely limits the severity of bronchospasm in young males.
Collapse
Affiliation(s)
- Abril Carbajal-García
- Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico; (A.C.-G.); (J.R.-G.); (M.F.C.-H.)
| | - Jorge Reyes-García
- Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico; (A.C.-G.); (J.R.-G.); (M.F.C.-H.)
| | - Verónica Díaz-Hernández
- Departamento de Embriología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico;
| | - María F. Casas-Hernández
- Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico; (A.C.-G.); (J.R.-G.); (M.F.C.-H.)
| | - Francisco Javier Flores-Murrieta
- Unidad de Investigación en Farmacología, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Mexico City 14080, Mexico;
- Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional, Mexico City 11340, Mexico
| | - Luis M. Montaño
- Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico; (A.C.-G.); (J.R.-G.); (M.F.C.-H.)
| |
Collapse
|
3
|
Babou Kammoe RB, Sévigny J. Extracellular nucleotides in smooth muscle contraction. Biochem Pharmacol 2024; 220:116005. [PMID: 38142836 DOI: 10.1016/j.bcp.2023.116005] [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: 08/24/2023] [Revised: 12/18/2023] [Accepted: 12/19/2023] [Indexed: 12/26/2023]
Abstract
Extracellular nucleotides and nucleosides are crucial signalling molecules, eliciting diverse biological responses in almost all organs and tissues. These molecules exert their effects by activating specific nucleotide receptors, which are finely regulated by ectonucleotidases that break down their ligands. In this comprehensive review, we aim to elucidate the relevance of extracellular nucleotides as signalling molecules in the context of smooth muscle contraction, considering the modulatory influence of ectonucleotidases on this intricate process. Specifically, we provide a detailed examination of the involvement of extracellular nucleotides in the contraction of non-vascular smooth muscles, including those found in the urinary bladder, the airways, the reproductive system, and the gastrointestinal tract. Furthermore, we present a broader overview of the role of extracellular nucleotides in vascular smooth muscle contraction.
Collapse
Affiliation(s)
- Romuald Brice Babou Kammoe
- Centre de Recherche du CHU de Québec - Université Laval, Québec City, QC G1V 4G2, Canada; Département de microbiologie-infectiologie et d'immunologie, Faculté de Médecine, Université Laval, Québec City, QC G1V 0A6, Canada
| | - Jean Sévigny
- Centre de Recherche du CHU de Québec - Université Laval, Québec City, QC G1V 4G2, Canada; Département de microbiologie-infectiologie et d'immunologie, Faculté de Médecine, Université Laval, Québec City, QC G1V 0A6, Canada.
| |
Collapse
|
4
|
Engevik KA, Scribano FJ, Gebert JT, Perry JL, Crawford SE, Hyser JM. Distribution of P2Y and P2X purinergic receptor expression within the intestine. Am J Physiol Gastrointest Liver Physiol 2024; 326:G107-G119. [PMID: 37987757 PMCID: PMC11208031 DOI: 10.1152/ajpgi.00108.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 11/06/2023] [Accepted: 11/16/2023] [Indexed: 11/22/2023]
Abstract
Nucleotides are potent extracellular signaling molecules during homeostasis, infection, and injury due to their ability to activate purinergic receptors. The nucleotide ATP activates P2X receptors (P2RXs), whereas the nucleotides ADP, ATP, UTP, and UDP-glucose selectively activate different P2Y receptors (P2RYs). Several studies have established crucial roles for P2 receptors during intestinal inflammatory and infectious diseases, yet the most extensive characterization of purinergic signaling has focused on immune cells and the central and enteric nervous systems. As epithelial cells serve as the first barrier against irritants and infection, we hypothesized that the gut epithelium may express multiple purinergic receptors that respond to extracellular nucleotide signals. Using the Human Protein Atlas and Gut Cell Survey, we queried single-cell RNA sequencing (RNAseq) data for the P2 purinergic receptors in the small and large intestines. In silico analysis reveals robust mRNA expression of P2RY1, P2RY2, P2RY11, and P2RX4 throughout the gastrointestinal tract. Human intestinal organoids exhibited a similar expression pattern with a prominent expression of P2RY1, P2RY2, and P2RX4, but this purinergic receptor repertoire was not conserved in T84, Caco2, and HT29 intestinal epithelial cell lines. Finally, P2YR1 and P2YR2 agonists elicited robust calcium responses in human intestinal organoids, but calcium responses were weaker or absent in the cell lines. These findings suggest that the gastrointestinal epithelia respond to extracellular purinergic signaling via P2RY1, P2RY2, P2RY11, and P2RX4 receptors and highlight the benefit of using intestinal organoids as a model of intestinal purinergic signaling.NEW & NOTEWORTHY Several studies have revealed crucial roles for P2 receptors during inflammatory and infectious diseases, however, these have largely been demonstrated in immune cells and the enteric nervous system. Although epithelial cells serve as the first barrier against infection and inflammation, the role of purinergic signaling within the gastrointestinal tract remains largely unknown. This work expands our knowledge of purinergic receptor distribution and relative expression along the intestine.
Collapse
Affiliation(s)
- Kristen A Engevik
- Alkek Center for Metagenomics and Microbiome Research, Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States
| | - Francesca J Scribano
- Alkek Center for Metagenomics and Microbiome Research, Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States
| | - J Thomas Gebert
- Alkek Center for Metagenomics and Microbiome Research, Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States
| | - Jacob L Perry
- Alkek Center for Metagenomics and Microbiome Research, Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States
| | - Sue E Crawford
- Alkek Center for Metagenomics and Microbiome Research, Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States
| | - Joseph M Hyser
- Alkek Center for Metagenomics and Microbiome Research, Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States
| |
Collapse
|
5
|
Evangelinellis MM, Souza RF, Mendes CE, Castelucci P. Effects of a P2X7 receptor antagonist on myenteric neurons in the distal colon of an experimental rat model of ulcerative colitis. Histochem Cell Biol 2021; 157:65-81. [PMID: 34626216 DOI: 10.1007/s00418-021-02039-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2021] [Indexed: 12/20/2022]
Abstract
Inflammatory bowel diseases (IBDs) are chronic diseases of the gastrointestinal tract that include ulcerative colitis and Crohn's disease and affect enteric neurons. Research has shown that Brilliant Blue G (BBG), a P2X7 receptor antagonist, restores enteric neurons following ischemia and reperfusion. This study aimed to evaluate the effect of BBG on myenteric neurons of the distal colon in an experimental rat model of ulcerative colitis. Colitis was induced by injection of 2,4,6-trinitrobenzene sulfonic acid (TNBS) into the large intestine. BBG was administered 1 h after colitis induction and for five consecutive days thereafter. Distal colons were collected 24 h or 7 days after TNBS injection. The animals were divided into 24-h and 7-day sham (vehicle injection rather than colitis induction), 24-h colitis, 24-h BBG, 7-day colitis and 7-day BBG groups. The disease activity index (DAI), neuronal density and profile of neuronal nitric oxide synthase (nNOS)-, choline acetyltransferase (ChAT)- and P2X7 receptor-immunoreactive enteric neurons were analyzed, and histological analysis was performed. The results showed recovery of the DAI and histological tissue integrity in the BBG groups compared to those in the colitis groups. In addition, the numbers of neurons positive for nNOS, ChAT and the P2X7 receptor per area were decreased in the colitis groups, and these measures were recovered in the BBG groups. Neuronal size was increased in the colitis groups and restored in the BBG groups. In conclusion, BBG is effective in improving experimental ulcerative colitis, and the P2X7 receptor may be a therapeutic target.
Collapse
Affiliation(s)
- Mariá Munhoz Evangelinellis
- Department of Surgery, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, Av. Prof. Dr Orlando Marques de Paiva, 87, São Paulo, CEP 05508-270, Brazil
| | - Roberta Figueiroa Souza
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Dr. Lineu Prestes, 2415, São Paulo, CEP 05508-900, Brazil
| | - Cristina Eusébio Mendes
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Dr. Lineu Prestes, 2415, São Paulo, CEP 05508-900, Brazil
| | - Patricia Castelucci
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Dr. Lineu Prestes, 2415, São Paulo, CEP 05508-900, Brazil.
| |
Collapse
|
6
|
Zhang ZY, Zhang F, Weng ZJ, Wu HG, Zhou Y, Han D, Li GN, Liu HR, Cui YH. Regulatory effect of mild moxibustion on P2X3 receptors in spinal cord, anterior cingulate cortex and thalamic ventral posterolateral nucleus of rats with IBS visceral hyperalgesia. JOURNAL OF ACUPUNCTURE AND TUINA SCIENCE 2021. [DOI: 10.1007/s11726-021-1254-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
7
|
King BF. P2X3 receptors participate in purinergic inhibition of gastrointestinal smooth muscle. Auton Neurosci 2021; 234:102830. [PMID: 34116466 DOI: 10.1016/j.autneu.2021.102830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/11/2021] [Accepted: 05/28/2021] [Indexed: 10/21/2022]
Abstract
The ATP analogue α,β-meATP is a potent relaxant of gastrointestinal smooth muscle, but its molecular target is uncertain inside the gut. α,β-meATP relaxed the carbachol-precontracted guinea-pig taenia coli in a concentration-dependent manner (EC50, 2.0 ± 0.1 μM). A luciferase-based assay confirmed that α,β-meATP solutions were minimally contaminated with ATP. α,β-meATP-evoked relaxations were inhibited by the competitive P2Y1 antagonist MRS2179 (pA2 = 5.36), but also by the competitive P2X3 antagonist, A-317491 (pA2 = 5.51). When MRS2179 and A-317491 were applied together, residual α,β-meATP responses converted from brief to prolonged relaxations. Sodium nitroprusside (a nitric oxide donor) also caused prolonged relaxations. Immunohistochemistry revealed that P2X3 receptors were present in myenteric ganglion cells and their varicose nerve terminals. The amplitude of α,β-meATP responses was not inhibited by TTX (NaV channel blocker) and ωCgTx (N-type CaV channel blocker). However, responses to α,β-meATP were inhibited by TEA (non-selective K+-channel blocker), indicating that relaxations involved opening K+-channels. The findings of this study are consistent with the conclusion that α,β-meATP stimulates Ca2+-permeable P2X3 receptors on varicose nerve terminals to release inhibitory nucleotides: 1) ATP and β-NAD release results in P2Y1-mediated brief relaxations; 2) another released transmitter (possibly NO) results in prolonged relaxations. Prejunctional P2X3 receptors represent a purinergic feed-forward mechanism to augment the action of inhibitory nerves on gut motility. This positive feed-forward mechanism may counter-balance the known negative feedback mechanism caused by adenosine and prejunctional A1 receptors on inhibitory motor nerves.
Collapse
Affiliation(s)
- Brian F King
- University College London (UCL), Research Department of Neuroscience, Pharmacology & Physiology (NPP), Gower Street, London WC1E 6BT, United Kingdom.
| |
Collapse
|
8
|
Sanders KM, Mutafova-Yambolieva VN. Neurotransmitters responsible for purinergic motor neurotransmission and regulation of GI motility. Auton Neurosci 2021; 234:102829. [PMID: 34146957 DOI: 10.1016/j.autneu.2021.102829] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 05/25/2021] [Accepted: 05/28/2021] [Indexed: 12/17/2022]
Abstract
Classical concepts of peripheral neurotransmission were insufficient to explain enteric inhibitory neurotransmission. Geoffrey Burnstock and colleagues developed the idea that ATP or a related purine satisfies the criteria for a neurotransmitter and serves as an enteric inhibitory neurotransmitter in GI muscles. Cloning of purinergic receptors and development of specific drugs and transgenic mice have shown that enteric inhibitory responses depend upon P2Y1 receptors in post-junctional cells. The post-junctional cells that transduce purinergic neurotransmitters in the GI tract are PDGFRα+ cells and not smooth muscle cells (SMCs). PDGFRα+ cells express P2Y1 receptors, are activated by enteric inhibitory nerve stimulation and generate Ca2+ oscillations, express small-conductance Ca2+-activated K+ channels (SK3), and generate outward currents when exposed to P2Y1 agonists. These properties are consistent with post-junctional purinergic responses, and similar responses and effectors are not functional in SMCs. Refinements in methodologies to measure purines in tissue superfusates, such as high-performance liquid chromatography (HPLC) coupled with etheno-derivatization of purines and fluorescence detection, revealed that multiple purines are released during stimulation of intrinsic nerves. β-NAD+ and other purines, better satisfy criteria for the purinergic neurotransmitter than ATP. HPLC has also allowed better detection of purine metabolites, and coupled with isolation of specific types of post-junctional cells, has provided new concepts about deactivation of purine neurotransmitters. In spite of steady progress, many unknowns about purinergic neurotransmission remain and require additional investigation to understand this important regulatory mechanism in GI motility.
Collapse
Affiliation(s)
- Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada, School of Medicine, 1664 North Virginia Street, Reno, NV 89557, USA.
| | - Violeta N Mutafova-Yambolieva
- Department of Physiology and Cell Biology, University of Nevada, School of Medicine, 1664 North Virginia Street, Reno, NV 89557, USA
| |
Collapse
|
9
|
Peteu SF, Russell SA, Galligan JJ, Swain GM. An Electrochemical ATP Biosensor with Enzymes Entrapped within a PEDOT Film. ELECTROANAL 2020. [DOI: 10.1002/elan.202060397] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Serban F. Peteu
- Department of Chemistry Michigan State University Department of Chemistry 578 S. Shaw Lane East Lansing MI 48824-1322 USA
| | - Skye A. Russell
- Department of Chemistry Michigan State University Department of Chemistry 578 S. Shaw Lane East Lansing MI 48824-1322 USA
| | - James J. Galligan
- Department of Pharmacology and Toxicology Michigan State University B440 Life Sciences Building East Lansing MI 48824-1317 USA
- Neuroscience Program, Giltner Hall 293 Farm Lane, Room 108 East Lansing MI 48824-1101 USA
| | - Greg M. Swain
- Department of Chemistry Michigan State University Department of Chemistry 578 S. Shaw Lane East Lansing MI 48824-1322 USA
- Neuroscience Program, Giltner Hall 293 Farm Lane, Room 108 East Lansing MI 48824-1101 USA
| |
Collapse
|
10
|
P2X 3 Receptor in Primary Afferent Neurons Mediates the Relief of Visceral Hypersensitivity by Electroacupuncture in an Irritable Bowel Syndrome Rat Model. Gastroenterol Res Pract 2020; 2020:8186106. [PMID: 33014041 PMCID: PMC7519176 DOI: 10.1155/2020/8186106] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/21/2020] [Accepted: 08/28/2020] [Indexed: 02/06/2023] Open
Abstract
Background Electroacupuncture (EA) has been confirmed effectiveness in the treatment of irritable bowel syndrome (IBS), and P2X3 receptors in the peripheral and central neurons participate in the acupuncture-mediated relief of the visceral pain in IBS. Objective To reveal the neurobiological mechanism that P2X3 receptor of colonic primary sensory neurons in the dorsal root ganglia of the lumbosacral segment is involved in the alleviation of visceral hypersensitivity by EA in an IBS rat model. Methods The IBS chronic visceral pain rat model was established according to the method of Al-Chaer et al. EA at the bilateral He-Mu points, including ST25 and ST37, was conducted for intervention. The behavioral studies, histopathology of colon, electrophysiology, immunofluorescence histochemistry, and real-time polymerase chain reaction assays were used to observe the role of P2X3 receptor in the colon and related DRG in relieving visceral hypersensitivity by EA. Results EA significantly reduced the behavior scores of the IBS rats under different levels (20, 40, 60, 80 mmHg) of colorectal distention stimulation and downregulated the expression levels of P2X3 receptor protein and mRNA in colon and related DRG of the IBS rats. EA also regulated the electrical properties of the membranes, including the resting membrane potential, rheobase, and action potential of colon-associated DRG neurons in the IBS rats. Conclusion EA can regulate the P2X3 receptor protein and mRNA expression levels in the colon and related DRG of IBS rats with visceral pain and then regulate the excitatory properties of DRG neurons.
Collapse
|
11
|
Souza RF, Evangelinellis MM, Mendes CE, Righetti M, Lourenço MCS, Castelucci P. P2X7 receptor antagonist recovers ileum myenteric neurons after experimental ulcerative colitis. World J Gastrointest Pathophysiol 2020; 11:84-103. [PMID: 32587788 PMCID: PMC7303980 DOI: 10.4291/wjgp.v11.i4.84] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 04/04/2020] [Accepted: 04/18/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The P2X7 receptor is expressed by enteric neurons and enteric glial cells. Studies have demonstrated that administration of a P2X7 receptor antagonist, brilliant blue G (BBG), prevents neuronal loss.
AIM To report the effects of BBG in ileum enteric neurons immunoreactive (ir) following experimental ulcerative colitis in Rattus norvegicus albinus.
METHODS 2,4,6-trinitrobenzene sulfonic acid (TNBS group, n = 5) was injected into the distal colon. BBG (50 mg/kg, BBG group, n = 5) or vehicle (sham group, n = 5) was given subcutaneously 1 h after TNBS. The animals were euthanized after 24 h, and the ileum was removed. Immunohistochemistry was performed on the myenteric plexus to evaluate immunoreactivity for P2X7 receptor, neuronal nitric oxide synthase (nNOS), choline acetyltransferase (ChAT), HuC/D and glial fibrillary acidic protein.
RESULTS The numbers of nNOS-, ChAT-, HuC/D-ir neurons and glial fibrillary acidic protein-ir glial cells were decreased in the TNBS group and recovered in the BBG group. The neuronal profile area (μm2) demonstrated that nNOS-ir neurons decreased in the TNBS group and recovered in the BBG group. There were no differences in the profile areas of ChAT- and HuC/D-ir neurons.
CONCLUSION Our data conclude that ileum myenteric neurons and glial cells were affected by ulcerative colitis and that treatment with BBG had a neuroprotective effect. Thus, these results demonstrate that the P2X7 receptor may be an important target in therapeutic strategies.
Collapse
Affiliation(s)
| | - Mariá Munhoz Evangelinellis
- Department of Surgery, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo 05508-900, Brazil
| | | | - Marta Righetti
- Department of Anatomy, University of São Paulo, São Paulo 05508-900, Brazil
| | | | | |
Collapse
|
12
|
Aihara Y, Fukuda Y, Takizawa A, Osakabe N, Aida T, Tanaka K, Yoshikawa S, Karasuyama H, Adachi T. Visualization of mechanical stress-mediated Ca 2+ signaling in the gut using intravital imaging. BIOSCIENCE OF MICROBIOTA, FOOD AND HEALTH 2020; 39:209-218. [PMID: 33117619 PMCID: PMC7573108 DOI: 10.12938/bmfh.2019-054] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Accepted: 05/22/2020] [Indexed: 12/15/2022]
Abstract
Mechanosensory systems have been implicated in the maintenance of gut homeostasis, but details on the related mechanisms are scarce. Recently, we generated a conditional Ca2+ biosensor yellow cameleon 3.60 (YC3.60)-expressing transgenic mouse model and established a five-dimensional (5D; x, y, z, time, and Ca2+) intravital imaging system for investigating lymphoid tissues and enteric epithelial cell responses. To validate this gut-sensing system, we visualized responses of enteric nervous system (ENS) cells in Nestin-Cre/YC3.60flox mice with specific YC3.60 expression. The ENS, including the myenteric (Auerbach's) and submucous (Meissner's) plexuses, could be visualized without staining in this mouse line, indicating that the probe produced sufficient fluorescent intensity. Furthermore, the myenteric plexus exhibited Ca2+ signaling during peristalsis without stimulation. Nerve endings on the surface of enteric epithelia also exhibited Ca2+ signaling without stimulation. Mechanical stress induced transient salient Ca2+ flux in the myenteric plexus and in enteric epithelial cells in the Nestin-Cre/YC3.60 and the CAG-Cre/YC3.60 lines, respectively. Furthermore, the potential TRPM7 inhibitors were shown to attenuate mechanical stress-mediated Ca2+ signaling. These data indicate that the present intravital imaging system can be used to visualize mechanosensory Ca2+ signaling in ENS cells and enteric epithelial cells.
Collapse
Affiliation(s)
- Yoshiko Aihara
- Department of Agrobioscience, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai, Nada, Kobe, Hyogo 657-8501, Japan
- Department of Immunology, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan
| | - Yota Fukuda
- Department of Immunology, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan
- Department of Bioscience and Engineering, Shibaura Institute of Technology, 307 Fukasaku, Minuma-ku, Saitama, Saitama 337-5780, Japan
| | - Akiyoshi Takizawa
- Department of Agrobioscience, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai, Nada, Kobe, Hyogo 657-8501, Japan
| | - Naomi Osakabe
- Department of Bioscience and Engineering, Shibaura Institute of Technology, 307 Fukasaku, Minuma-ku, Saitama, Saitama 337-5780, Japan
| | - Tomomi Aida
- Department of Molecular Neuroscience, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan
| | - Kohichi Tanaka
- Department of Molecular Neuroscience, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan
| | - Soichiro Yoshikawa
- Department of Immune Regulation, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Hajime Karasuyama
- Department of Immune Regulation, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Takahiro Adachi
- Department of Immunology, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan
| |
Collapse
|
13
|
Park IK, Kim JH, Park CG, Kim MY, Parajuli SP, Hong CS, Choi S, Jun JY. Effects of ATP on Pacemaker Activity of Interstitial Cells of Cajal from the Mouse Small Intestine. Chonnam Med J 2018; 54:63-71. [PMID: 29399568 PMCID: PMC5794481 DOI: 10.4068/cmj.2018.54.1.63] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 10/23/2017] [Accepted: 10/25/2017] [Indexed: 01/23/2023] Open
Abstract
Purinergic receptors play an important role in regulating gastrointestinal (GI) motility. Interstitial cells of Cajal (ICCs) are pacemaker cells that regulate GI smooth muscle activity. We studied the functional roles of external adenosine 5′-triphosphate (ATP) on pacemaker activity in cultured ICCs from mouse small intestines by using the whole-cell patch clamp technique and intracellular Ca2+ ([Ca2+]i) imaging. External ATP dose-dependently depolarized the resting membrane and produced tonic inward pacemaker currents, and these effects were antagonized by suramin, a purinergic P2 receptor antagonist. ATP-induced effects on pacemaker currents were suppressed by an external Na+-free solution and inhibited by the nonselective cation channel blockers, flufenamic acid and niflumic acid. The removal of external Ca2+ or treatment with thapsigargin (inhibitor of Ca2+ uptake into endoplasmic reticulum) inhibited the ATP-induced effects on pacemaker currents. Spontaneous [Ca2+]i oscillations were enhanced by external ATP. These results suggest that external ATP modulates pacemaker activity by activating nonselective cation channels via external Ca2+ influx and [Ca2+]i release from the endoplasmic reticulum. Thus, it seems that activating the purinergic P2 receptor may modulate GI motility by acting on ICCs in the small intestine.
Collapse
Affiliation(s)
- Il Koo Park
- Department of Internal Medicine, College of Medicine, Chosun University, Gwangju, Korea
| | - Jin Ho Kim
- Department of Neurology, College of Medicine, Chosun University, Gwangju, Korea
| | - Chan Guk Park
- Department of Internal Medicine, College of Medicine, Chosun University, Gwangju, Korea
| | - Man Yoo Kim
- Department of Internal Medicine, College of Medicine, Chosun University, Gwangju, Korea
| | | | - Chan Sik Hong
- Department of Physiology, College of Medicine, Chosun University, Gwangju, Korea
| | - Seok Choi
- Department of Physiology, College of Medicine, Chosun University, Gwangju, Korea
| | - Jae Yeoul Jun
- Department of Physiology, College of Medicine, Chosun University, Gwangju, Korea
| |
Collapse
|
14
|
Durnin L, Lees A, Manzoor S, Sasse KC, Sanders KM, Mutafova-Yambolieva VN. Loss of nitric oxide-mediated inhibition of purine neurotransmitter release in the colon in the absence of interstitial cells of Cajal. Am J Physiol Gastrointest Liver Physiol 2017; 313:G419-G433. [PMID: 28705804 PMCID: PMC5792210 DOI: 10.1152/ajpgi.00045.2017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 06/26/2017] [Accepted: 07/11/2017] [Indexed: 01/31/2023]
Abstract
Regulation of colonic motility depends on the integrity of enteric inhibitory neurotransmission mediated by nitric oxide (NO), purine neurotransmitters, and neuropeptides. Intramuscular interstitial cells of Cajal (ICC-IM) and platelet-derived growth factor receptor-α-positive (PDGFRα+) cells are involved in generating responses to NO and purine neurotransmitters, respectively. Previous studies have suggested a decreased nitrergic and increased purinergic neurotransmission in KitW/KitW-v (W/Wv ) mice that display lesions in ICC-IM along the gastrointestinal tract. However, contributions of NO to these phenotypes have not been evaluated. We used small-chamber superfusion assays and HPLC to measure the spontaneous and electrical field stimulation (EFS)-evoked release of nicotinamide adenine dinucleotide (NAD+)/ADP-ribose, uridine adenosine tetraphosphate (Up4A), adenosine 5'-triphosphate (ATP), and metabolites from the tunica muscularis of human, monkey, and murine colons and circular muscle of monkey colon, and we tested drugs that modulate NO levels or blocked NO receptors. NO inhibited EFS-evoked release of purines in the colon via presynaptic neuromodulation. Colons from W/Wv, Nos1-/- , and Prkg1-/- mice displayed augmented neural release of purines that was likely due to altered nitrergic neuromodulation. Colons from W/Wv mice demonstrated decreased nitrergic and increased purinergic relaxations in response to nerve stimulation. W/Wv mouse colons demonstrated reduced Nos1 expression and reduced NO release. Our results suggest that enhanced purinergic neurotransmission may compensate for the loss of nitrergic neurotransmission in muscles with partial loss of ICC. The interactions between nitrergic and purinergic neurotransmission in the colon provide novel insight into the role of neurotransmitters and effector cells in the neural regulation of gastrointestinal motility.NEW & NOTEWORTHY This is the first study investigating the role of nitric oxide (NO) and intramuscular interstitial cells of Cajal (ICC-IM) in modulating neural release of purines in colon. We found that NO inhibited release of purines in human, monkey, and murine colons and that colons from KitW/KitW-v (W/Wv ) mice, which present with partial loss of ICC-IM, demonstrated augmented neural release of purines. Interactions between nitrergic and purinergic neurotransmission may affect motility in disease conditions with ICC-IM deficiencies.
Collapse
Affiliation(s)
- Leonie Durnin
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada; and
| | - Andrea Lees
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada; and
| | - Sheerien Manzoor
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada; and
| | | | - Kenton M. Sanders
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada; and
| | | |
Collapse
|
15
|
Liñán-Rico A, Ochoa-Cortes F, Zuleta-Alarcon A, Alhaj M, Tili E, Enneking J, Harzman A, Grants I, Bergese S, Christofi FL. UTP - Gated Signaling Pathways of 5-HT Release from BON Cells as a Model of Human Enterochromaffin Cells. Front Pharmacol 2017; 8:429. [PMID: 28751862 PMCID: PMC5508028 DOI: 10.3389/fphar.2017.00429] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 06/15/2017] [Indexed: 12/30/2022] Open
Abstract
Background: Enterochromaffin cells (EC) synthesize and release 5-HT and ATP to trigger or modulate gut neural reflexes and transmit information about visceral/pain sensation. Alterations in 5-HT signaling mechanisms may contribute to the pathogenesis of IBD or IBS, but the pharmacologic or molecular mechanisms modulating Ca2+-dependent 5-HT release are not understood. Previous studies indicated that purinergic signaling via ATP and ADP is an important mechanism in modulation of 5-HT release. However, EC cells also respond to UTP and UDP suggesting uridine triphosphate receptor and signaling pathways are involved as well. We tested the hypothesis that UTP is a regulator of 5-HT release in human EC cells. Methods: UTP signaling mechanisms were studied in BON cells, a human EC model, using Fluo-4/Ca2+imaging, patch-clamp, pharmacological analysis, immunohistochemistry, western blots and qPCR. 5-HT release was monitored in BON or EC isolated from human gut surgical specimens (hEC). Results: UTP, UTPγS, UDP or ATP induced Ca2+oscillations in BON. UTP evoked a biphasic concentration-dependent Ca2+response. Cells responded in the order of UTP, ATP > UTPγS > UDP >> MRS2768, BzATP, α,β-MeATP > MRS2365, MRS2690, and NF546. Different proportions of cells activated by UTP and ATP also responded to UTPγS (P2Y4, 50% cells), UDP (P2Y6, 30%), UTPγS and UDP (14%) or MRS2768 (<3%). UTP Ca2+responses were blocked with inhibitors of PLC, IP3R, SERCA Ca2+pump, La3+sensitive Ca2+channels or chelation of intracellular free Ca2+ by BAPTA/AM. Inhibitors of L-type, TRPC, ryanodine-Ca2+pools, PI3-Kinase, PKC or SRC-Kinase had no effect. UTP stimulated voltage-sensitive Ca2+currents (ICa), Vm-depolarization and inhibited IK (not IA) currents. An IKv7.2/7.3 K+ channel blocker XE-991 mimicked UTP-induced Vm-depolarization and blocked UTP-responses. XE-991 blocked IK and UTP caused further reduction. La3+ or PLC inhibitors blocked UTP depolarization; PKC inhibitors, thapsigargin or zero Ca2+buffer did not. UTP stimulated 5-HT release in hEC expressing TPH1, 5-HT, P2Y4/P2Y6R. Zero-Ca2+buffer augmented Ca2+responses and 5-HT release. Conclusion: UTP activates a predominant P2Y4R pathway to trigger Ca2+oscillations via internal Ca2+mobilization through a PLC/IP3/IP3R/SERCA Ca2+signaling pathway to stimulate 5-HT release; Ca2+influx is inhibitory. UTP-induced Vm-depolarization depends on PLC signaling and an unidentified K channel (which appears independent of Ca2+oscillations or Ica/VOCC). UTP-gated signaling pathways triggered by activation of P2Y4R stimulate 5-HT release.
Collapse
Affiliation(s)
- Andromeda Liñán-Rico
- Department of Anesthesiology, The Wexner Medical Center at The Ohio State University, ColumbusOH, United States
| | - Fernando Ochoa-Cortes
- Department of Anesthesiology, The Wexner Medical Center at The Ohio State University, ColumbusOH, United States
| | - Alix Zuleta-Alarcon
- Department of Anesthesiology, The Wexner Medical Center at The Ohio State University, ColumbusOH, United States
| | - Mazin Alhaj
- Department of Anesthesiology, The Wexner Medical Center at The Ohio State University, ColumbusOH, United States
| | - Esmerina Tili
- Department of Anesthesiology, The Wexner Medical Center at The Ohio State University, ColumbusOH, United States
- Molecular Virology, Immunology and Medical Genetics, The Wexner Medical Center at The Ohio State University, ColumbusOH, United States
| | - Josh Enneking
- Department of Anesthesiology, The Wexner Medical Center at The Ohio State University, ColumbusOH, United States
| | - Alan Harzman
- Department of Surgery, The Wexner Medical Center at The Ohio State University, ColumbusOH, United States
| | - Iveta Grants
- Department of Anesthesiology, The Wexner Medical Center at The Ohio State University, ColumbusOH, United States
| | - Sergio Bergese
- Department of Anesthesiology, The Wexner Medical Center at The Ohio State University, ColumbusOH, United States
| | - Fievos L. Christofi
- Department of Anesthesiology, The Wexner Medical Center at The Ohio State University, ColumbusOH, United States
| |
Collapse
|
16
|
Purinergic Signalling in the Gut. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 891:91-112. [PMID: 27379638 DOI: 10.1007/978-3-319-27592-5_10] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The article will begin with the discovery of purinergic inhibitory neuromuscular transmission in the 1960s/1970s, the proposal for purinergic cotransmission in 1976 and the recognition that sympathetic nerves release adenosine 5'-triphosphate (ATP), noradrenaline and neuropeptide Y, while non-adrenergic, non-cholinergic inhibitory nerve cotransmitters are ATP, nitric oxide and vasoactive intestinal polypeptide in variable proportions in different regions of the gut. Later, purinergic synaptic transmission in the myenteric and submucosal plexuses was established and purinergic receptors expressed by both glial and interstitial cells. The focus will then be on purinergic mechanosensory transduction involving release of ATP from mucosal epithelial cells during distension to activate P2X3 receptors on submucosal sensory nerve endings. The responses of low threshold fibres mediate enteric reflex activity via intrinsic sensory nerves, while high threshold fibres initiate pain via extrinsic sensory nerves. Finally, the involvement of purinergic signalling in an animal model of colitis will be presented, showing that during distension there is increased ATP release, increased P2X3 receptor expression on calcitonin gene-related peptide-labelled sensory neurons and increased sensory nerve activity.
Collapse
|
17
|
de Souza SRG, de Miranda Neto MH, Martins Perles JVC, Vieira Frez FC, Zignani I, Ramalho FV, Hermes-Uliana C, Bossolani GDP, Zanoni JN. Antioxidant Effects of the Quercetin in the Jejunal Myenteric Innervation of Diabetic Rats. Front Med (Lausanne) 2017; 4:8. [PMID: 28224126 PMCID: PMC5293826 DOI: 10.3389/fmed.2017.00008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 01/19/2017] [Indexed: 12/31/2022] Open
Abstract
Purpose Enteric glial cells (EGCs) exert a critical role in the structural integrity, defense, and metabolic function of enteric neurons. Diabetes mellitus is a chronic disease characterized by metabolic disorders and chronic autonomic neuropathy. Quercetin supplementation, which is a potent antioxidant, has been used in order to reduce the effects of diabetes-induced oxidative stress. The purpose of this research was to investigate the effects of quercetin supplementation in the drinking water at a daily dose of 40 mg on the glial cells and neurons in the jejunum of diabetic rats. Materials and methods Twenty 90-day-old male adult Wistar rats were split into four groups: normoglycemic control (C), normoglycemic control supplemented with quercetin (Q), diabetic (D), and diabetic supplemented with quercetin (DQ). After 120 days, the jejunums were collected, and immunohistochemical technique was performed to label S-100-immunoreactive glial cells and HuC/D-immunoreactive neurons. Results An intense neuronal and glial reduction was observed in the jejunum of diabetic rats. Quercetin displayed neuroprotective effects due to reduced cell body areas of neurons and glial cells in Q and DQ groups compared to their controls (C and D groups). Interestingly, quercetin prevented the glial and neuronal loss with a higher density for the HuC/D-immunoreactive neurons (23.06%) and for the S100-immunoreactive glial cells (14.55%) in DQ group compared to D group. Conclusion Quercetin supplementation promoted neuroprotective effects through the reduction of neuronal and glial body areas and a slight prevention of neuronal and glial density reduction.
Collapse
Affiliation(s)
- Sara R Garcia de Souza
- Department of Morphological Sciences, Universidade Estadual de Maringá , Maringá, Paraná , Brazil
| | | | | | | | - Isabela Zignani
- Department of Morphological Sciences, Universidade Estadual de Maringá , Maringá, Paraná , Brazil
| | - Francielle Veiga Ramalho
- Department of Morphological Sciences, Universidade Estadual de Maringá , Maringá, Paraná , Brazil
| | | | | | | |
Collapse
|
18
|
Rodriguez-Tapia ES, Naidoo V, DeVries M, Perez-Medina A, Galligan JJ. R-Type Ca 2+ channels couple to inhibitory neurotransmission to the longitudinal muscle in the guinea-pig ileum. Exp Physiol 2017; 102:299-313. [PMID: 28008669 DOI: 10.1113/ep086027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 12/13/2016] [Indexed: 12/17/2022]
Abstract
NEW FINDINGS What is the central question of this study? Subtypes of enteric neurons are coded by the neurotransmitters they synthesize, but it is not known whether enteric neuron subtypes might also be coded by other proteins, including calcium channel subtypes controlling neurotransmitter release. What is the main finding and its importance? Our data indicate that guinea-pig ileum myenteric neuron subtypes may be coded by calcium channel subtypes. We found that R-type calcium channels are expressed by inhibitory but not excitatory longitudinal muscle motoneurons. R-Type calcium channels are also not expressed by circular muscle inhibitory motoneurons. Calcium channel subtype-selective antagonists could be used to target subtypes of neurons to treat gastrointestinal motility disorders. There is evidence that R-type Ca2+ channels contribute to synaptic transmission in the myenteric plexus. It is unknown whether R-type Ca2+ channels contribute to neuromuscular transmission. We measured the effects of the nitric oxide synthase inhibitor nitro-l-arginine (NLA), Ca2+ channel blockers and apamin (SK channel blocker) on neurogenic relaxations and contractions of the guinea-pig ileum longitudinal muscle-myenteric plexus (LMMP) in vitro. We used intracellular recordings to measure inhibitory junction potentials. Immunohistochemical techniques localized R-type Ca2+ channel protein in the LMMP and circular muscle. Cadmium chloride (pan-Ca2+ channel blocker) blocked and NLA and NiCl2 (R-type Ca2+ channel blocker) reduced neurogenic relaxations in a non-additive manner. Nickel chloride did not alter neurogenic cholinergic contractions, but it potentiated neurogenic non-cholinergic contractions. Relaxations were inhibited by apamin, NiCl2 and NLA and were blocked by combined application of these drugs. Relaxations were reduced by NiCl2 or ω-conotoxin (N-type Ca2+ channel blocker) and were blocked by combined application of these drugs. Longitudinal muscle inhibitory junction potentials were inhibited by NiCl2 but not MRS 2179 (P2Y1 receptor antagonist). Circular muscle inhibitory junction potentials were blocked by apamin, MRS 2179, ω-conotoxin and CdCl2 but not NiCl2 . We conclude that neuronal R-type Ca2+ channels contribute to inhibitory neurotransmission to longitudinal muscle but less so or not all in the circular muscle of the guinea-pig ileum.
Collapse
Affiliation(s)
| | - Vinogran Naidoo
- The Neuroscience Program, Michigan State University, East Lansing, MI, 48824, USA
| | - Matthew DeVries
- Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI, 48824, USA
| | - Alberto Perez-Medina
- Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI, 48824, USA
| | - James J Galligan
- The Neuroscience Program, Michigan State University, East Lansing, MI, 48824, USA.,Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI, 48824, USA
| |
Collapse
|
19
|
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: 64] [Impact Index Per Article: 8.0] [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.
Collapse
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
| |
Collapse
|
20
|
Durnin L, Moreland N, Lees A, Mutafova-Yambolieva VN. A commonly used ecto-ATPase inhibitor, ARL-67156, blocks degradation of ADP more than the degradation of ATP in murine colon. Neurogastroenterol Motil 2016; 28:1370-81. [PMID: 27060478 PMCID: PMC5002237 DOI: 10.1111/nmo.12836] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 03/14/2016] [Indexed: 01/24/2023]
Abstract
BACKGROUND Adenosine 5'-triphosphate (ATP) is released extracellularly as a neurotransmitter and an autocrine or paracrine mediator in numerous systems, including the gastrointestinal tract. It is rapidly degraded to active and inactive metabolites by membrane-bound enzymes. Investigators frequently use inhibitors of ATP hydrolysis such as ARL-67156 and POM-1 to suppress the catabolism of ATP and prolong its effects in pharmacological studies. Our aim was to investigate directly the effects of ARL-67156 and POM-1 on the degradation of ATP and adenosine 5'-diphosphate (ADP) in mouse colonic muscles. METHODS The degradation of ATP and ADP was evaluated by superfusing tissues with 1,N(6) -etheno-ATP (eATP) and 1,N(6) -etheno-ADP (eADP) as substrates and monitoring the decrease in substrate and increase in products (i.e., eADP, eAMP, and e-adenosine) by high-performance liquid chromatography techniques with fluorescence detection. Relaxation responses to etheno-derivatized and non-derivatized ATP and ADP were examined in isometric tension experiments. KEY RESULTS ARL-67156 inhibits the degradation of ADP but not of ATP, whereas POM-1 inhibits the degradation of ATP but not of ADP in murine colonic muscles. Consequently, ARL-67156 enhances relaxation responses to both ATP and ADP, whereas POM-1 reduces relaxation to ATP and does not affect relaxation to ADP. CONCLUSIONS & INFERENCES Studies that use ARL-67156 to inhibit ATP degradation in smooth muscle likely evaluate responses to accumulated ADP rather than ATP. POM-1 appears to be a more selective inhibitor of ATP degradation in the mouse colon. The choice of pharmacological tools in studies on extracellular ATP signaling may affect the interpretation of experimental data in functional studies.
Collapse
Affiliation(s)
- L. Durnin
- Department of Physiology and Cell Biology; University of Nevada School of Medicine; Reno NV USA
| | - N. Moreland
- Department of Physiology and Cell Biology; University of Nevada School of Medicine; Reno NV USA
| | - A. Lees
- Department of Physiology and Cell Biology; University of Nevada School of Medicine; Reno NV USA
| | | |
Collapse
|
21
|
P2Y receptor-mediated transient relaxation of rat longitudinal ileum preparations involves phospholipase C activation, intracellular Ca(2+) release and SK channel activation. Acta Pharmacol Sin 2016; 37:617-28. [PMID: 27018177 DOI: 10.1038/aps.2015.137] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 12/10/2015] [Indexed: 12/13/2022] Open
Abstract
AIM Purinergic signaling plays a major role in the enteric nervous system, where it governs gut motility through a number of P2X and P2Y receptors. The aim of this study was to investigate the P2Y receptor-mediated motility in rat longitudinal ileum preparations. METHODS Ileum smooth muscle strips were prepared from rats, and fixed in an organ bath. Isometric contraction and relaxation responses of the muscle strips were measured with force transducers. Drugs were applied by adding of stock solutions to the organ bath to yield the individual final concentrations. RESULTS Application of the non-hydrolyzable P2 receptor agonists α,β-Me-ATP or 2-Me-S-ADP (10, 100 μmol/L) dose-dependently elicited a transient relaxation response followed by a sustained contraction. The relaxation response was largely blocked by SK channel blockers apamin (500 nmol/L) and UCL1684 (10 μmol/L), PLC inhibitor U73122 (100 μmol/L), IP3 receptor blocker 2-APB (100 μmol/L) or sarcoendoplasmic Ca(2+) ATPase inhibitor thapsigargin (1 μmol/L), but not affected by atropine, NO synthase blocker L-NAME or tetrodotoxin. Furthermore, α,β-Me-ATP-induced relaxation was suppressed by P2Y1 receptor antagonist MRS2179 (50 μmol/L) or P2Y13 receptor antagonist MRS2211 (100 μmol/L), and was abolished by co-application of the two antagonists, whereas 2-Me-S-ADP-induced relaxation was abolished by P2Y6 receptor antagonist MRS2578 (50 μmol/L). In addition, P2Y1 receptor antagonist MRS2500 (1 μmol/L) not only abolished α,β-Me-ATP-induced relaxation, but also suppressed 2-Me-S-ADP-induced relaxation. CONCLUSION P2Y receptor agonist-induced transient relaxation of rat ileum smooth muscle strips is mediated predominantly by P2Y1 receptor, but also by P2Y6 and P2Y13 receptors, and involves PLC, IP3, Ca(2+) release and SK channel activation, but is independent of acetylcholine and NO release.
Collapse
|
22
|
King BF. Purinergic signalling in the enteric nervous system (An overview of current perspectives). Auton Neurosci 2015; 191:141-7. [PMID: 26049261 DOI: 10.1016/j.autneu.2015.05.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Purinergic Signalling in the Enteric Nervous System involves the regulated release of ATP (or a structurally-related nucleotide) which activates an extensive suite of membrane-inserted receptors (P2X and P2Y subtypes) on a variety of cell types in the gastrointestinal tract. P2X receptors are gated ion-channels permeable to sodium, potassium and calcium. They depolarise cells, act as a pathway for calcium influx to activate calcium-dependent processes and initiate gene transcription, interact at a molecular level as a form of self-regulation with lipids within the cell wall (e.g. PIP2) and cross-react with other membrane-inserted receptors to regulate their activity (e.g. nAChRs). P2Y receptors are metabotropic receptors that couple to G-proteins. They may release calcium ions from intracellular stores to activate calcium-dependent processes, but also may activate calcium-independent signalling pathways and influence gene transcription. Originally ATP was a candidate only for NANC neurotransmission, for inhibitory motoneurons supplying the muscularis externa of the gastrointestinal tract and bringing about the fast IJP. Purinergic signalling later included neuron-neuron signalling in the ENS, via the production of either fast or slow EPSPs. Later still, purinergic signalling included the neuro-epithelial synapse-for efferent signalling to epithelia cells participating in secretion and absorption, and afferent signalling for chemoreception and mechanoreception at the surface of the mucosa. Many aspects of purinergic signalling have since been addressed in a series of highly-focussed and authoritative reviews. In this overview however, the current focus is on key aspects of purinergic signalling where there remains uncertainty and ambiguity, with the view to stimulating further research in these areas.
Collapse
Affiliation(s)
- Brian F King
- University College London (UCL), Department of Neuroscience, Physiology and Pharmacology (NPP), Royal Free Campus, Rowland Hill Street, Hampstead, London NW3 2PF, United Kingdom.
| |
Collapse
|
23
|
Abstract
The role of adenosine 5'-triphosphate (ATP) as a major intracellular energy source is well-established. In addition, ATP and related nucleotides have widespread extracellular actions via the ionotropic P2X (ligand-gated cation channels) and metabotropic P2Y (G protein-coupled) receptors. Numerous experimental techniques, including myography, electrophysiology and biochemical measurement of neurotransmitter release, have been used to show that ATP has several major roles as a neurotransmitter in peripheral nerves. When released from enteric nerves of the gastrointestinal tract it acts as an inhibitory neurotransmitter, mediating descending muscle relaxation during peristalsis. ATP is also an excitatory cotransmitter in autonomic nerves; 1) It is costored with noradrenaline in synaptic vesicles in postganglionic sympathetic nerves innervating smooth muscle preparations, such as the vas deferens and most arteries. When coreleased with noradrenaline, ATP acts at postjunctional P2X1 receptors to evoke depolarisation, Ca(2+) influx, Ca(2+) sensitisation and contraction. 2) ATP is also coreleased with acetylcholine from postganglionic parasympathetic nerves innervating the urinary bladder and again acts at postjunctional P2X1 receptors, and possibly also a P2X1+4 heteromer, to elicit smooth muscle contraction. In both cases the neurotransmitter actions of ATP are terminated by dephosphorylation by extracellular, membrane-bound enzymes and soluble nucleotidases released from postganglionic nerves. There are indications of an increased contribution of ATP to control of blood pressure in hypertension, but further research is needed to clarify this possibility. More promising is the upregulation of P2X receptors in dysfunctional bladder, including interstitial cystitis, idiopathic detrusor instability and overactive bladder syndrome. Consequently, these roles of ATP are of great therapeutic interest and are increasingly being targeted by pharmaceutical companies.
Collapse
Affiliation(s)
- Charles Kennedy
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, United Kingdom.
| |
Collapse
|
24
|
Pathophysiological role of extracellular purinergic mediators in the control of intestinal inflammation. Mediators Inflamm 2015; 2015:427125. [PMID: 25944982 PMCID: PMC4405224 DOI: 10.1155/2015/427125] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 09/30/2014] [Indexed: 12/19/2022] Open
Abstract
Purinergic mediators such as adenosine 5′-triphosphate (ATP) are released into the extracellular compartment from damaged tissues and activated immune cells. They are then recognized by multiple purinergic P2X and P2Y receptors. Release and recognition of extracellular ATP are associated with both the development and the resolution of inflammation and infection. Accumulating evidence has recently suggested the potential of purinergic receptors as novel targets for drugs for treating intestinal disorders, including intestinal inflammation and irritable bowel syndrome. In this review, we highlight recent findings regarding the pathophysiological role of purinergic mediators in the development of intestinal inflammation.
Collapse
|
25
|
Weng ZJ, Wu LY, Zhou CL, Dou CZ, Shi Y, Liu HR, Wu HG. Effect of electroacupuncture on P2X3 receptor regulation in the peripheral and central nervous systems of rats with visceral pain caused by irritable bowel syndrome. Purinergic Signal 2015; 11:321-9. [PMID: 25809868 DOI: 10.1007/s11302-015-9447-6] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 02/16/2015] [Indexed: 12/15/2022] Open
Abstract
The aim of this study is to investigate the role of the purinergic receptor P2X3 in the peripheral and central nervous systems during acupuncture treatment for the visceral pain of irritable bowel syndrome (IBS). A total of 24 8-day-old Sprague-Dawley (SD) neonatal male rats (SPF grade) were stimulated using colorectal distention (CRD) when the rats were awake. The modeling lasted for 2 weeks with one stimulation per day. After 6 weeks, the rats were randomly divided into three groups of eight each: (1) the normal group (NG, n = 8); (2) the model group (MG, n = 8); and (3) the model + electroacupuncture group (EA, n = 8) that received electroacupuncture at a needling depth of 5 mm at the Shangjuxu (ST37, bilateral) and Tianshu (ST25, bilateral) acupoints. The parameters of the Han's acupoint nerve stimulator (HANS) were as follows: sparse-dense wave with a frequency of 2/100 Hz, current of 2 mA, 20 min/stimulation, and one stimulation per day; the treatment was provided for seven consecutive days. At the sixth week after the treatment, the abdominal withdrawal reflex (AWR) score was determined; immunofluorescence and immunohistochemistry were used to measure the expression of the P2X3 receptor in myenteric plexus neurons, prefrontal cortex, and anterior cingulate cortex; and, a real-time PCR assay was performed to measure the expression of P2X3 messenger RNA (mRNA) in the dorsal root ganglion (DRG) and spinal cord. After stimulation with CRD, the expression levels of the P2X3 receptor in the inter-colonic myenteric plexus, DRG, spinal cord, prefrontal cortex, and anterior cingulate cortex were upregulated, and the sensitivity of the rats to IBS visceral pain was increased. Electroacupuncture (EA) could downregulate the expression of the P2X3 receptor and ease the sensitivity to visceral pain. The P2X3 receptor plays an important role in IBS visceral pain. The different levels of P2X3 in the peripheral enteric nervous system and central nervous system mediate the effects of the EA treatment of the visceral hyperalgesia of IBS.
Collapse
Affiliation(s)
- Z J Weng
- Key Laboratory of Acupuncture and Immunological Effects, Shanghai Research Institute of Acupuncture and Meridian, 650 South Wanping Road, Shanghai, 200030, China
| | | | | | | | | | | | | |
Collapse
|
26
|
Uridine adenosine tetraphosphate is a novel neurogenic P2Y1 receptor activator in the gut. Proc Natl Acad Sci U S A 2014; 111:15821-6. [PMID: 25341729 DOI: 10.1073/pnas.1409078111] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Enteric purinergic motor neurotransmission, acting through P2Y1 receptors (P2Y1R), mediates inhibitory neural control of the intestines. Recent studies have shown that NAD(+) and ADP ribose better meet criteria for enteric inhibitory neurotransmitters in colon than ATP or ADP. Here we report that human and murine colon muscles also release uridine adenosine tetraphosphate (Up4A) spontaneously and upon stimulation of enteric neurons. Release of Up4A was reduced by tetrodotoxin, suggesting that at least a portion of Up4A is of neural origin. Up4A caused relaxation (human and murine colons) and hyperpolarization (murine colon) that was blocked by the P2Y1R antagonist, MRS 2500, and by apamin, an inhibitor of Ca(2+)-activated small-conductance K(+) (SK) channels. Up4A responses were greatly reduced or absent in colons of P2ry1(-/-) mice. Up4A induced P2Y1R-SK-channel-mediated hyperpolarization in isolated PDGFRα(+) cells, which are postjunctional targets for purinergic neurotransmission. Up4A caused MRS 2500-sensitive Ca(2+) transients in human 1321N1 astrocytoma cells expressing human P2Y1R. Up4A was more potent than ATP, ADP, NAD(+), or ADP ribose in colonic muscles. In murine distal colon Up4A elicited transient P2Y1R-mediated relaxation followed by a suramin-sensitive contraction. HPLC analysis of Up4A degradation suggests that exogenous Up4A first forms UMP and ATP in the human colon and UDP and ADP in the murine colon. Adenosine then is generated by extracellular catabolism of ATP and ADP. However, the relaxation and hyperpolarization responses to Up4A are not mediated by its metabolites. This study shows that Up4A is a potent native agonist for P2Y1R and SK-channel activation in human and mouse colon.
Collapse
|
27
|
Mizuno MS, Crisma AR, Borelli P, Schäfer BT, Silveira MP, Castelucci P. Distribution of the P2X2 receptor and chemical coding in ileal enteric neurons of obese male mice ( ob/ob). World J Gastroenterol 2014; 20:13911-13919. [PMID: 25320527 PMCID: PMC4194573 DOI: 10.3748/wjg.v20.i38.13911] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 04/29/2014] [Accepted: 06/13/2014] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the colocalization, density and profile of neuronal areas of enteric neurons in the ileum of male obese mice.
METHODS: The small intestinal samples of male mice in an obese group (OG) (C57BL/6J ob/ob) and a control group (CG) (+/+) were used. The tissues were analyzed using a double immunostaining technique for immunoreactivity (ir) of the P2X2 receptor, nitric oxide synthase (NOS), choline acetyl transferase (ChAT) and calretinin (Calr). Also, we investigated the density and profile of neuronal areas of the NOS-, ChAT- and Calr-ir neurons in the myenteric plexus. Myenteric neurons were labeled using an NADH-diaphorase histochemical staining method.
RESULTS: The analysis demonstrated that the P2X2 receptor was expressed in the cytoplasm and in the nuclear and cytoplasmic membranes only in the CG. Neuronal density values (neuron/cm2) decreased 31% (CG: 6579 ± 837; OG: 4556 ± 407) and 16.5% (CG: 7796 ± 528; OG: 6513 ± 610) in the NOS-ir and calretinin-ir neurons in the OG, respectively (P < 0.05). Density of ChAT-ir (CG: 6200 ± 310; OG: 8125 ± 749) neurons significantly increased 31% in the OG (P < 0.05). Neuron size studies demonstrated that NOS, ChAT, and Calr-ir neurons did not differ significantly between the CG and OG groups. The examination of NADH-diaphorase-positive myenteric neurons revealed an overall similarity between the OG and CG.
CONCLUSION: Obesity may exert its effects by promoting a decrease in P2X2 receptor expression and modifications in the density of the NOS-ir, ChAT-ir and CalR-ir myenteric neurons.
Collapse
|
28
|
Jiménez M, Clavé P, Accarino A, Gallego D. Purinergic neuromuscular transmission in the gastrointestinal tract; functional basis for future clinical and pharmacological studies. Br J Pharmacol 2014; 171:4360-75. [PMID: 24910216 DOI: 10.1111/bph.12802] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 05/14/2014] [Accepted: 05/24/2014] [Indexed: 12/13/2022] Open
Abstract
Nerve-mediated relaxation is necessary for the correct accomplishment of gastrointestinal (GI) motility. In the GI tract, NO and a purine are probably released by the same inhibitory motor neuron as inhibitory co-transmitters. The P2Y1 receptor has been recently identified as the receptor responsible for purinergic smooth muscle hyperpolarization and relaxation in the human gut. This finding has been confirmed in P2Y1 -deficient mice where purinergic neurotransmission is absent and transit time impaired. However, the mechanisms responsible for nerve-mediated relaxation, including the identification of the purinergic neurotransmitter(s) itself, are still debatable. Possibly different mechanisms of nerve-mediated relaxation are present in the GI tract. Functional demonstration of purinergic neuromuscular transmission has not been correlated with structural studies. Labelling of purinergic neurons is still experimental and is not performed in routine pathology studies from human samples, even when possible neuromuscular impairment is suspected. Accordingly, the contribution of purinergic neurotransmission in neuromuscular diseases affecting GI motility is not known. In this review, we have focused on the physiological mechanisms responsible for nerve-mediated purinergic relaxation providing the functional basis for possible future clinical and pharmacological studies on GI motility targeting purine receptors.
Collapse
Affiliation(s)
- Marcel Jiménez
- Department of Cell Biology, Physiology and Immunology, Neurosciences Institute, Universitat Autònoma de Barcelona, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Barcelona, Spain
| | | | | | | |
Collapse
|
29
|
Martínez-Cutillas M, Gil V, Gallego D, Mañé N, Clavé P, Martín MT, Jiménez M. α,β-meATP mimics the effects of the purinergic neurotransmitter in the human and rat colon. Eur J Pharmacol 2014; 740:442-54. [PMID: 24998877 DOI: 10.1016/j.ejphar.2014.06.048] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 06/13/2014] [Accepted: 06/17/2014] [Indexed: 02/05/2023]
Abstract
The purine receptor involved in inhibitory responses in the gastrointestinal tract has been recently identified. P2Y1 receptor activation mediates the fast component of the inhibitory junction potential (IJPf) and the non-nitrergic relaxation. The aim of the present work has been to investigate which purinergic agonist better mimics endogenous responses. We used different agonist and antagonist of P2 receptors. Contractility and microelectrode experiments were used to compare the effects of exogenously added purines and electrical field stimulation (EFS)-induced nerve mediated effects in rat and human colonic strips. In rat colon, the IJPf and EFS-induced inhibition of contractions were concentration-dependently inhibited by the P2Y1 antagonist MRS2500 but not by iso-PPADS or NF023 (P2X antagonists) up to 1 μM. In samples from human colon, EFS-induced inhibition of contractions was inhibited by either MRS2500 or apamin (1 μM) but not by iso-PPADS. In both species, α,β-meATP, a stable analog of ATP, caused inhibition of spontaneous contractions. α,β-meATP effect was concentration-dependent (EC50: 2.7 μM rat, 4.4 μM human) and was antagonized by either MRS2500 or apamin but unaffected by P2X antagonists. ATP, ADP, β-NAD and ADP-ribose inhibited spontaneous contractions but did not show the same sensitivity profile to purine receptor antagonists as EFS-induced inhibition of contractions. The effect of α,β-meATP is due to P2Y1 receptor activation leading the opening of sKca channels. Accordingly, α,β-meATP mimics the endogenous purinergic mediator. In contrast, exogenously added putative neurotransmitters do not exactly mimic the endogenous mediator. Quick degradation by ecto-nuclease or different distribution of receptors (junctionally vs extrajunctionally) might explain these results.
Collapse
Affiliation(s)
- Míriam Martínez-Cutillas
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Víctor Gil
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Diana Gallego
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas, (CIBERehd), Instituto de Salud Carlos III, Barcelona, Spain
| | - Noemí Mañé
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Pere Clavé
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas, (CIBERehd), Instituto de Salud Carlos III, Barcelona, Spain; Fundació de Gastroenterologia Dr Vilardell and Department of Surgery, Hospital de Mataró, Mataró, Barcelona, Spain
| | - María Teresa Martín
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas, (CIBERehd), Instituto de Salud Carlos III, Barcelona, Spain
| | - Marcel Jiménez
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas, (CIBERehd), Instituto de Salud Carlos III, Barcelona, Spain.
| |
Collapse
|
30
|
Abstract
The article begins with a review of the main conceptual steps involved in the development of our understanding of purinergic signalling, including non-adrenergic, non-cholinergic (NANC) neurotransmission; identification of ATP as a NANC transmitter; purinergic cotransmission; recognition of two families of purinoceptors [P1 (adenosine) and P2 (ATP/ADP)]; and, later, cloning and characterisation of P1 (G protein-coupled), P2X (ion channel) and P2Y (G protein-coupled) receptor subtypes. Further studies have established the involvement of ATP in synaptic neurotransmission in both ganglia and in the central nervous system; long-term (trophic) purinergic signalling in cell proliferation, differentiation and death occurring in development and regeneration; and short-term purinergic signalling in neurotransmission, neuromodulation and secretion. ATP is released from most cell types in response to gentle mechanical stimulation and is rapidly degraded to adenosine by ecto-nucleotidases. This review then focuses on the pathophysiology of purinergic signalling in a wide variety of systems, including urinogenital, cardiovascular, airway, musculoskeletal and gastrointestinal. Consideration is also given to the involvement of purinoceptors in pain, cancer and diseases of the central nervous system. Purinergic therapeutic approaches for the treatment of some of these diseases are discussed.
Collapse
|
31
|
Verkhratsky A, Burnstock G. Biology of purinergic signalling: its ancient evolutionary roots, its omnipresence and its multiple functional significance. Bioessays 2014; 36:697-705. [PMID: 24782352 DOI: 10.1002/bies.201400024] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The purinergic signalling system, which utilises ATP, related nucleotides and adenosine as transmitter molecules, appeared very early in evolution: release mechanisms and ATP-degrading enzymes are operative in bacteria, and the first specific receptors are present in single cell eukaryotic protozoa and algae. Further evolution of the purinergic signalling system resulted in the development of multiple classes of purinoceptors, several pathways for release of nucleotides and adenosine, and a system of ectonucleotidases controlling extracellular levels of purinergic transmitters. The purinergic signalling system is expressed in virtually all types of tissues and cells, where it mediates numerous physiological reactions and contributes to pathological responses in a variety of diseases.
Collapse
Affiliation(s)
- Alexei Verkhratsky
- School of Biological Sciences, The University of Manchester, Manchester, UK; Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain; University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | | |
Collapse
|
32
|
Gallego D, Malagelada C, Accarino A, De Giorgio R, Malagelada JR, Azpiroz F, Jimenez M. Nitrergic and purinergic mechanisms evoke inhibitory neuromuscular transmission in the human small intestine. Neurogastroenterol Motil 2014; 26:419-29. [PMID: 24372768 DOI: 10.1111/nmo.12293] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 11/22/2013] [Indexed: 02/08/2023]
Abstract
BACKGROUND Inhibitory neuromuscular transmission in the human colon is due to nitrergic and purinergic (P2Y1 -mediated) inputs. The aim of this study was to determine the mechanisms of neuromuscular transmission in different regions of the human small intestine. METHODS Ileal (n = 6) and jejunal (n = 6) samples underwent histological examination and were studied using sharp microelectrodes in smooth muscle cells and conventional muscle bath techniques. Electrical field stimulation (EFS) was used to stimulate inhibitory neurons. KEY RESULTS No histological abnormalities were found. Resting membrane potential was -39.7 ± 1.5 and -45.5 ± 2.1 mV in the jejunum and ileum, respectively. Slow waves and spontaneous contractions were recorded at a frequency of about 8-9 and 6-7 cpm in the jejunum and ileum, respectively. In non-adrenergic, non-cholinergic conditions, EFS caused an inhibitory junction potential and mechanical relaxation. Both responses were blocked by tissue incubation with the nitric oxide synthase inhibitor (Nω-nitro-l-arginine 1 mM) and the P2Y1 receptor blocker 2'-deoxy-N(6) -methyladenosine 3',5'-bisphosphate tetrasodium salt (MRS2179; 10 μM). Both exogenous addition of sodium nitroprusside (1 μM) and the preferential P2Y1 receptor agonist ADPβS (1 μM) hyperpolarized and relaxed smooth muscle cells. MRS2179 (10 μM) blocked ADPβS-induced responses. CONCLUSIONS & INFERENCES Similar to colon, inhibitory neurotransmission in the human small intestine is mainly mediated by purinergic (via P2Y1 receptors) and nitrergic inhibitory neurotransmission. Similar mechanisms of inhibitory neurotransmission are present in different regions of the human intestine.
Collapse
Affiliation(s)
- D Gallego
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Barcelona, Spain; Department of Cell Biology, Physiology and Immunology and Neurosciences Institute, Universitat Autònoma de Barcelona, Barcelona, Spain
| | | | | | | | | | | | | |
Collapse
|
33
|
Burnstock G. Purinergic signalling in the gastrointestinal tract and related organs in health and disease. Purinergic Signal 2014; 10:3-50. [PMID: 24307520 PMCID: PMC3944042 DOI: 10.1007/s11302-013-9397-9] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 10/24/2013] [Indexed: 01/04/2023] Open
Abstract
Purinergic signalling plays major roles in the physiology and pathophysiology of digestive organs. Adenosine 5'-triphosphate (ATP), together with nitric oxide and vasoactive intestinal peptide, is a cotransmitter in non-adrenergic, non-cholinergic inhibitory neuromuscular transmission. P2X and P2Y receptors are widely expressed in myenteric and submucous enteric plexuses and participate in sympathetic transmission and neuromodulation involved in enteric reflex activities, as well as influencing gastric and intestinal epithelial secretion and vascular activities. Involvement of purinergic signalling has been identified in a variety of diseases, including inflammatory bowel disease, ischaemia, diabetes and cancer. Purinergic mechanosensory transduction forms the basis of enteric nociception, where ATP released from mucosal epithelial cells by distension activates nociceptive subepithelial primary afferent sensory fibres expressing P2X3 receptors to send messages to the pain centres in the central nervous system via interneurons in the spinal cord. Purinergic signalling is also involved in salivary gland and bile duct secretion.
Collapse
Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF, UK,
| |
Collapse
|
34
|
Tamada H, Hashitani H. Calcium responses in subserosal interstitial cells of the guinea-pig proximal colon. Neurogastroenterol Motil 2014; 26:115-23. [PMID: 24329947 DOI: 10.1111/nmo.12240] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 09/07/2013] [Indexed: 02/08/2023]
Abstract
BACKGROUND In the subserosal layer between the longitudinal muscle layer and mesothelium, heterogeneous populations of interstitial cells are distributed. As the distribution of nerve elements in this layer is sparse as compared with the nerve plexus layer or tunica muscularis, there may be unique communication among subserosal interstitial cells (SSICs). This study aimed to explore functional properties of SSICs. METHODS In subserosal preparations of the guinea-pig proximal colon, changes in intracellular Ca(2+) ([Ca(2+) ]i ) were visualized using Fluo-4 Ca(2+) imaging. Immunohistochemistry was also performed to identify the SSICs exhibiting Ca(2+) transients. KEY RESULTS A majority of SSICs responded to adenosine triphosphate (ATP, 10 μM) by increasing [Ca(2+) ]i , but remained quiescent during the application of acetylcholine (10 μM). ATP-induced Ca(2+) responses were mimicked by adenosine 5'-diphosphate (10 μM), MRS2365 (10 nM) but not α, β-methylene ATP (10 μM) or uridine triphosphate (10 μM), and could be reproduced in Ca(2+) -free solution, suggesting that ATP acts via P2Y receptors, most likely P2Y1 subtype, but not P2X receptors. Live staining of the same preparations after Ca(2+) imaging indicated the ATP-sensitive SSICs were not positive for c-Kit antibody, a specific marker for gastrointestinal interstitial cells of Cajal (ICC). Immunohistochemistry identified vimentin (mesenchymal cell marker)+/Kit- and SK3 (fibroblast-like cell (FLC) marker)+/Kit- cells that had a similar morphology to the ATP-sensitive SSICs in Ca(2+) imaging. CONCLUSIONS & INFERENCES A majority of the SSICs in the guinea-pig proximal colon, presumably FLC, are capable of responding to ATP and thus may contribute to smooth muscle relaxation upon stimulation with ATP released from non-neuronal cells.
Collapse
Affiliation(s)
- H Tamada
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Mizuho-ku, Nagoya, Japan; Japan Society for the Promotion of Science, Chiyoda-ku, Tokyo, Japan
| | | |
Collapse
|
35
|
Altomare A, Luca Guarino Sara Emerenziani MP, Cicala M, Drewes AM, Krarup AL, Brock C, Lottrup C, Frøkjaer JB, Souza RF, Nardone G, Compare D. Gastrointestinal sensitivity and gastroesophageal reflux disease. Ann N Y Acad Sci 2013; 1300:80-95. [PMID: 24117636 DOI: 10.1111/nyas.12236] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This paper reports on gastrointestinal sensitivity, including on the role of refluxate volume on the perception of reflux symptoms; experimental pain models that mimic mechanisms and symptoms of pain associated with esophageal diseases; the potential role of the acid receptor TRPV1 in the genesis of gastroesophageal reflux disease (GERD) symptoms; and roles for ATP and the purine and pyrimidine receptor subfamilies P1, P2X, and P2Y in the pathogenesis of GERD symptoms.
Collapse
Affiliation(s)
- Annamaria Altomare
- Department of Digestive Disease, Campus Bio-medico University, Rome, Italy
| | | | - Michele Cicala
- Department of Digestive Disease, Campus Bio-medico University, Rome, Italy
| | - Asbjørn Mohr Drewes
- Mech-Sense, Departments of Gastroenterology & Radiology, Aalborg University Hospital, Aalborg, Denmark
| | - Anne Lund Krarup
- Mech-Sense, Departments of Gastroenterology & Radiology, Aalborg University Hospital, Aalborg, Denmark
| | - Christina Brock
- Mech-Sense, Departments of Gastroenterology & Radiology, Aalborg University Hospital, Aalborg, Denmark
| | - Christian Lottrup
- Mech-Sense, Departments of Gastroenterology & Radiology, Aalborg University Hospital, Aalborg, Denmark
| | - Jens Brøndum Frøkjaer
- Mech-Sense, Departments of Gastroenterology & Radiology, Aalborg University Hospital, Aalborg, Denmark
| | - Rhonda F Souza
- Departments of Medicine, University of Texas Southwestern Medical Center and the VA North Texas Health Care System, Dallas, Texas
| | - Gerardo Nardone
- Department of Clinical and Experimental Medicine, Gastroenterology Unit, University "Federico II,", Naples, Italy
| | - Debora Compare
- Department of Clinical and Experimental Medicine, Gastroenterology Unit, University "Federico II,", Naples, Italy
| |
Collapse
|
36
|
Burnstock G. Introduction and perspective, historical note. Front Cell Neurosci 2013; 7:227. [PMID: 24312014 PMCID: PMC3836022 DOI: 10.3389/fncel.2013.00227] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 11/04/2013] [Indexed: 12/11/2022] Open
Abstract
P2 nucleotide receptors were proposed to consist of two subfamilies based on pharmacology in 1985, named P2X and P2Y receptors. Later, this was confirmed following cloning of the receptors for nucleotides and studies of transduction mechanisms in the early 1990s. P2X receptors are ion channels and seven subtypes are recognized that form trimeric homomultimers or heteromultimers. P2X receptors are involved in neuromuscular and synaptic neurotransmission and neuromodulation. They are also expressed on many types of non-neuronal cells to mediate smooth muscle contraction, secretion, and immune modulation. The emphasis in this review will be on the pathophysiology of P2X receptors and therapeutic potential of P2X receptor agonists and antagonists for neurodegenerative and inflammatory disorders, visceral and neuropathic pain, irritable bowel syndrome, diabetes, kidney failure, bladder incontinence and cancer, as well as disorders if the special senses, airways, skin, cardiovascular, and musculoskeletal systems.
Collapse
Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical SchoolLondon, UK
- Department of Pharmacology, The University of MelbourneMelbourne, VIC, Australia
| |
Collapse
|
37
|
Purinergic autocrine regulation of mechanosensitivity and serotonin release in a human EC model: ATP-gated P2X3 channels in EC are downregulated in ulcerative colitis. Inflamm Bowel Dis 2013; 19:2366-79. [PMID: 23917247 PMCID: PMC4037929 DOI: 10.1097/mib.0b013e31829ecf4d] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Alterations in 5-hydroxytryptamine (HT) signaling in inflamed gut may contribute to pathogenesis of inflammatory bowel diseases. Adenosine 5'-triphosphate (ATP) regulates mucosal-mechanosensory reflexes and ATP receptors are sensitive to mucosal inflammation. Yet, it remains unknown whether ATP can modulate 5-HT signaling in enterochromaffin cells (EC). We tested the novel purinergic hypothesis that ATP is a critical autocrine regulator of EC mechanosensitivity and whether EC expression of ATP-gated P2X3-ion channels is altered in inflammatory bowel diseases. METHODS Laser confocal (fluo-4) Ca imaging was performed in 1947 BON cells. Chemical stimulation or mechanical stimulation (MS) was used to study 5-HT or ATP release in human BON or surgical mucosal specimens, and purine receptors by reverse transcription-polymerase chain reaction, Western Blot, or P2X3-immunoreactivity in BON or 5-HT human EC (hEC) in 11 control and 10 severely inflamed ulcerative colitis (UC) cases. RESULTS ATP or MS triggered Ca-transients or 5-HT release in BON. ATP or adenosine diphosphate increased 5-HT release 5-fold. MS caused ATP release, detected after 5'ecto-ATPase inhibition by ARL67156. ARL67156 augmented and apyrase blocked Ca/5-HT mechanosensitive responses. 2-Methyl-thio-adenosine diphosphate 5'-monophosphate-evoked (P2Y1,12) or mechanically-evoked responses were blocked or augmented by a P2Y1,12 antagonist, MRS2179, in different cells or inhibited by U73122. A P2Y12 antagonist, 2MeSAMP, augmented responses. A P2X1,3 agonist, α,β-MeATP, triggered Ca responses, whereas a P2X1,2/3,3 antagonist, 2',3'-O-(2,4,6-trinitrophenyl)-ATP, blocked mechanical responses or cell-surface 5'ATP- labeling. In hEC, α,β-MeATP stimulated 5-HT release. In UC, P2X3-immunoreactivity decreased from 15% to 0.2% of 5-HThECs. Human mucosa and BON expressed P2X1, P2X3, P2X4, P2X5, P2Y1, P2Y2, P2Y4, P2Y6, P2Y11, and P2Y12R-messenger RNA transcripts. CONCLUSIONS ATP is a critical determinant of mechanosensation and 5-HT release via autocrine activation of slow P2Y1-phospholipase C/inositol-1,4,5-triphosphate-Ca or inhibitory P2Y12-purinergic pathways, and fast ATP-gated P2X3-channels. UC downregulation of P2X3-channels (or A2B) is postulated to mediate abnormal 5-HT signaling.
Collapse
|
38
|
Peri LE, Sanders KM, Mutafova-Yambolieva VN. Differential expression of genes related to purinergic signaling in smooth muscle cells, PDGFRα-positive cells, and interstitial cells of Cajal in the murine colon. Neurogastroenterol Motil 2013; 25:e609-20. [PMID: 23809506 PMCID: PMC3735650 DOI: 10.1111/nmo.12174] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Accepted: 05/26/2013] [Indexed: 12/19/2022]
Abstract
BACKGROUND Purinergic signaling provides regulation of colonic motility. Smooth muscle cells (SMC), interstitial cells of Cajal (ICC), and platelet-derived growth factor receptor α-positive (PDGFRα(+) ) cells are electrically coupled and form a functional (SIP) syncytium that constitutes the receptive field for motor neurotransmitters in the tunica muscularis. Each cell type in the SIP syncytium has specialized functions in mediating motor neurotransmission. We compared gene transcripts for purinergic receptors and membrane-bound enzymes for purine degradation expressed by each cell type of the SIP syncytium. METHODS Fluorescence-activated cell sorting (FACS) was used to purify SMC, ICC, and PDGFRα(+) cells from mixed cell populations of colonic muscles dispersed from reporter strains of mice with constitutive expression of green fluorescent proteins. Differential expression of functional groups of genes related to purinergic signaling was determined by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). KEY RESULTS We detected marked phenotypic differences among SMC, ICC, and PDGFRα(+) cells. Substantial numbers of genes of importance in purinergic neurotransmission were enriched in PDGFRα(+) cells in relation to SMC and ICC. Notably, genes related to mediating effects and extracellular biotransformation of enteric purinergic inhibitory neurotransmitters were strongly expressed by PDGFRα(+) cells. CONCLUSIONS & INFERENCES Our results demonstrate differential expression of genes for proteins involved in purinergic signaling in the SIP syncytium. These results may further clarify the specific functions of each cell type, identify novel biomarkers for postjunctional cells, and provide hypotheses for further studies to understand the physiological roles of cells of the SIP syncytium.
Collapse
Affiliation(s)
- L. E. Peri
- Department of Physiology and Cell Biology; University of Nevada School of Medicine; Reno; NV; USA
| | - K. M. Sanders
- Department of Physiology and Cell Biology; University of Nevada School of Medicine; Reno; NV; USA
| | | |
Collapse
|
39
|
Qi R, Yang W, Chen J. Role of enteric glial cells in gastric motility in diabetic rats at different stages. ACTA ACUST UNITED AC 2013; 33:496-500. [PMID: 23904367 DOI: 10.1007/s11596-013-1148-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 10/31/2012] [Indexed: 02/07/2023]
Abstract
Diabetes patients tend to have the gastrointestinal motility disorder. Although the relationship between the motility disorder and both the neurons and Cajal cells in the enteric nervous system (ENS) is well established, little is known about the role of enteric glial cells (EGCs) in gastric motility in diabetes. This study aimed to examine the expression of the glial marker S100B and morphology of EGCs in gastric tissues and the relationship between activated EGCs and the damage of gastric emptying in diabetic models. The diabetic model of rat was induced with 1% streptozotocin (STZ). The model rats at 7-14 days and at 56-63 days were defined as early diabetic rats and advanced diabetic rats, respectively, and normal rats at the two time periods served as their corresponding controls. The gastric emptying rate of the rats was tested by using the phenol red solution. The ultrastructure of EGCs in the gastric antrum was observed by the transmission electron microscopy, and the expression of S100B in the myenteric plexus was immunohistochemically detected. The results showed that the gastric emptying rate was significantly increased in the early diabetic rats and decreased in the advanced diabetic rats when compared with their corresponding control rats (P<0.01 for both). The ultrastructure of EGCs was mostly normal in both the early diabetic and control groups. Vacuolization of mitochondria and expansion of endoplasmic reticulum occurred in both the advanced diabetic group and its control group, and even the structure of smooth muscle cells and intestinal neurons was destroyed in the advanced diabetic group. The expression level of S100B in the advanced diabetic group was significantly decreased compared with its control group (P<0.05). It was obviously increased in the early diabetic control group when compared with the advanced diabetic control group (P<0.05). However, there was no significant difference in the S100B expression between the early diabetic group and its control group (P>0.05). The findings suggested that the gastric motility dysfunction in diabetes may be associated with the changes of morphology and number of EGCs in the myenteric plexus.
Collapse
Affiliation(s)
- Ran Qi
- Department of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Wei Yang
- Department of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Jie Chen
- Department of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
| |
Collapse
|
40
|
Fei G, Fang X, Wang GD, Liu S, Wang XY, Xia Y, Wood JD. Neurogenic mucosal bicarbonate secretion in guinea pig duodenum. Br J Pharmacol 2013; 168:880-90. [PMID: 22994306 DOI: 10.1111/j.1476-5381.2012.02218.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Revised: 08/24/2012] [Accepted: 08/31/2012] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE To test a hypothesis that: (i) duodenal pH and osmolarity are individually controlled at constant set points by negative feedback control centred in the enteric nervous system (ENS); (ii) the purinergic P2Y(1) receptor subtype is expressed by non-cholinergic secretomotor/vasodilator neurons, which represent the final common excitatory pathway from the ENS to the bicarbonate secretory glands. EXPERIMENTAL APPROACH Ussing chamber and pH-stat methods investigated involvement of the P2Y(1) receptor in neurogenic stimulation of mucosal bicarbonate (HCO(3)(-)) secretion in guinea pig duodenum. KEY RESULTS ATP increased HCO(3)(-) secretion with an EC(50) of 160 nM. MRS2179, a selective P2Y(1) purinergic receptor antagonist, suppressed ATP-evoked HCO(3)(-) secretion by 47% and Cl(-) secretion by 63%. Enteric neuronal blockade by tetrodotoxin or exposure to a selective vasoactive intestinal peptide (VIP, VPAC(1)) receptor antagonist suppressed ATP-evoked HCO(3)(-) secretion by 61 and 41%, respectively, and Cl- by 97 and 70% respectively. Pretreatment with the muscarinic antagonist, scopolamine did not alter ATP-evoked HCO3(-) or Cl(-) secretion. CONCLUSION AND IMPLICATIONS Whereas acid directly stimulates the mucosa to release ATP and stimulate HCO(3)(-) secretion in a cytoprotective manner, neurogenically evoked HCO(3)(-) secretion accounts for feedback control of optimal luminal pH for digestion. ATP stimulates duodenal HCO(3)(-) secretion through an excitatory action at purinergic P2Y(1) receptors on neurons in the submucosal division of the ENS. Stimulation of the VIPergic non-cholinergic secretomotor/vasodilator neurons, which are one of three classes of secretomotor neurons, accounts for most, if not all, of the neurogenic secretory response evoked by ATP.
Collapse
Affiliation(s)
- G Fei
- Department of Physiology and Cell Biology, Ohio State University College of Medicine, Columbus, OH, USA
| | | | | | | | | | | | | |
Collapse
|
41
|
Antonioli L, Colucci R, Pellegrini C, Giustarini G, Tuccori M, Blandizzi C, Fornai M. The role of purinergic pathways in the pathophysiology of gut diseases: pharmacological modulation and potential therapeutic applications. Pharmacol Ther 2013; 139:157-88. [PMID: 23588157 DOI: 10.1016/j.pharmthera.2013.04.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 03/15/2013] [Indexed: 02/08/2023]
Abstract
Gut homeostasis results from complex neuro-immune interactions aimed at triggering stereotypical and specific programs of coordinated mucosal secretion and powerful motor propulsion. A prominent role in the regulation of this highly integrated network, comprising a variety of immune/inflammatory cells and the enteric nervous system, is played by purinergic mediators. The cells of the digestive tract are literally plunged into a "biological sea" of functionally active nucleotides and nucleosides, which carry out the critical task of driving regulatory interventions on cellular functions through the activation of P1 and P2 receptors. Intensive research efforts are being made to achieve an integrated view of the purinergic system, since it is emerging that the various components of purinergic pathways (i.e., enzymes, transporters, mediators and receptors) are mutually linked entities, deputed to finely modulating the magnitude and the duration of purinergic signaling, and that alterations occurring in this balanced network could be intimately involved in the pathophysiology of several gut disorders. This review article intends to provide a critical appraisal of current knowledge on the purinergic system role in the regulation of gastrointestinal functions, considering these pathways as a whole integrated network, which is capable of finely controlling the levels of bioactive nucleotides and nucleosides in the biophase of their respective receptors. Special attention is paid to the mechanisms through which alterations in the various compartments of the purinergic system could contribute to the pathophysiology of gut disorders, and to the possibility of counteracting such dysfunctions by means of pharmacological interventions on purinergic molecular targets.
Collapse
Affiliation(s)
- Luca Antonioli
- Department of Clinical and Experimental Medicine, University of Pisa, Italy.
| | | | | | | | | | | | | |
Collapse
|
42
|
Abstract
After some early hints, cotransmission was proposed in 1976 and then "chemical coding" later established for sympathetic nerves (noradrenaline/norepinephrine, adenosine 5'-triphosphate (ATP), and neuropeptide Y), parasympathetic nerves (acetylcholine, ATP, and vasoactive intestinal polypeptide (VIP)), enteric nonadrenergic, noncholinergic inhibitory nerves (ATP, nitric oxide, and VIP), and sensory-motor nerves (calcitonin gene-related peptide, substance P, and ATP). ATP is a primitive signaling molecule that has been retained as a cotransmitter in most, if not all, nerve types in both the peripheral and central nervous systems. Neuropeptides coreleased with small molecule neurotransmitters in autonomic nerves do not usually act as cotransmitters but rather as prejunctional neuromodulators or trophic factors. Autonomic cotransmission offers subtle, local variation in physiological control mechanisms, rather than the dominance of inflexible central control mechanisms envisaged earlier. The variety of information imparted by a single neuron then greatly increases the sophistication and complexity of local control mechanisms. Cotransmitter composition shows considerable plasticity in development and aging, in pathophysiological conditions and following trauma or surgery. For example, ATP appears to become a more prominent cotransmitter in inflammatory and stress conditions.
Collapse
Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, London, UK and Department of Pharmacology, University of Melbourne, Australia.
| |
Collapse
|
43
|
Furuya S, Furuya K. Roles of substance P and ATP in the subepithelial fibroblasts of rat intestinal villi. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 304:133-89. [PMID: 23809436 DOI: 10.1016/b978-0-12-407696-9.00003-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The ingestion of food and water induces chemical and mechanical signals that trigger peristaltic reflexes and also villous movement in the gut. In the intestinal villi, subepithelial fibroblasts under the epithelium form contractile cellular networks and closely contact to the varicosities of substance P and nonsubstance P afferent neurons. Subepithelial fibroblasts of the duodenal villi possess purinergic receptor P2Y1 and tachykinin receptor NK1. ATP and substance P induce increase in intracellular Ca(2+) and cell contraction in subepithelial fibroblasts. They are highly mechanosensitive and release ATP by mechanical stimuli. Released ATP spreads to form an ATP "cloud" with nearly 1μM concentration and activates the surroundings via P2Y1 and afferent neurons via P2X receptors. These findings suggest that villous subepithelial fibroblasts and afferent neurons interact via ATP and substance P. This mutual interaction may play important roles in the signal transduction of mechano reflex pathways including a coordinate villous movement and also in the maturation of the structure and function of the intestinal villi.
Collapse
Affiliation(s)
- Sonoko Furuya
- Section of Brain Structure Information, Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki, Japan.
| | | |
Collapse
|
44
|
Lecca D, Ceruti S, Fumagalli M, Abbracchio MP. Purinergic trophic signalling in glial cells: functional effects and modulation of cell proliferation, differentiation, and death. Purinergic Signal 2012; 8:539-57. [PMID: 22528683 PMCID: PMC3360088 DOI: 10.1007/s11302-012-9310-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Accepted: 09/09/2011] [Indexed: 12/15/2022] Open
Abstract
In the last decades, the discovery that glial cells do not only fill in the empty space among neurons or furnish them with trophic support but are rather essential participants to the various activities of the central and peripheral nervous system has fostered the search for the signalling pathways controlling their functions. Since the early 1990s, purines were foreseen as some of the most promising candidate molecules. Originally just a hypothesis, this has become a certainty as experimental evidence accumulated over years, as demonstrated by the exponentially growing number of articles related to the role of extracellular nucleotides and nucleosides in controlling glial cell functions. Indeed, as new functions for already known glial cells (for example, the ability of parenchymal astrocytes to behave as stem cells) or new subtypes of glial cells (for example, NG2(+) cells, also called polydendrocytes) are discovered also, new actions and new targets for the purinergic system are identified. Thus, glial purinergic receptors have emerged as new possible pharmacological targets for various acute and chronic pathologies, such as stroke, traumatic brain and spinal cord injury, demyelinating diseases, trigeminal pain and migraine, and retinopathies. In this article, we will summarize the most important and promising actions mediated by extracellular purines and pyrimidines in controlling the functions, survival, and differentiation of the various "classical" types of glial cells (i.e., astrocytes, oligodendrocytes, microglial cells, Müller cells, satellite glial cells, and enteric glial cells) but also of some rather new members of the family (e.g., polydendrocytes) and of other cells somehow related to glial cells (e.g., pericytes and spinal cord ependymal cells).
Collapse
Affiliation(s)
- Davide Lecca
- Laboratory of Molecular and Cellular Pharmacology of Purinergic Transmission, Department of Pharmacological Sciences, Università degli Studi di Milano, via Balzaretti, 9-Milan, 20133 Italy
| | - Stefania Ceruti
- Laboratory of Molecular and Cellular Pharmacology of Purinergic Transmission, Department of Pharmacological Sciences, Università degli Studi di Milano, via Balzaretti, 9-Milan, 20133 Italy
| | - Marta Fumagalli
- Laboratory of Molecular and Cellular Pharmacology of Purinergic Transmission, Department of Pharmacological Sciences, Università degli Studi di Milano, via Balzaretti, 9-Milan, 20133 Italy
| | - Maria P. Abbracchio
- Laboratory of Molecular and Cellular Pharmacology of Purinergic Transmission, Department of Pharmacological Sciences, Università degli Studi di Milano, via Balzaretti, 9-Milan, 20133 Italy
| |
Collapse
|
45
|
Wolf-Johnston AS, Hanna-Mitchell AT, Buffington CA, Shinde S, Roppolo JR, Mayer E, Birder LA. Alterations in the non-neuronal acetylcholine synthesis and release machinery in esophageal epithelium. Life Sci 2012; 91:1065-9. [PMID: 22569297 DOI: 10.1016/j.lfs.2012.04.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2011] [Revised: 03/12/2012] [Accepted: 04/13/2012] [Indexed: 02/07/2023]
Abstract
AIMS A non-neuronal cholinergic system has been described in epithelial cells including that of the urinary bladder (urothelium) and the upper gastrointestinal tract (esophagus). Epithelial dysfunction has been implicated in the pathophysiology of persistent pain conditions such as painful bladder syndrome as well as functional heartburn. For example, alterations in the ability to synthesize and release acetylcholine may contribute to changes in epithelial sensory and barrier function associated with a number of functional genitourinary and intestinal disorders. MAIN METHODS We examined using immunoblot, acetylcholine (ACh)-synthesis and release components in cat esophageal mucosa and whether elements of these components are altered in a naturally occurring model of chronic idiopathic cystitis termed feline interstitial cystitis (FIC). KEY FINDINGS We identified proteins involved in ACh synthesis and release (high affinity choline transporter, CHT1; ACh synthesizing enzyme choline acetyltransferase ChAT and carnitine acetyltransferase CarAT; vesicular ACh transporter VAChT and the organic cation transporter isoforms 1-3 or OCT-1-3) in cat esophageal mucosa. Significant alterations in CHT, ChAT, VAChT and OCT-1 were detected in the esophageal mucosa from FIC cats. Changes in the vesicular nucleotide transporter (VNUT) and the junctional protein pan-cadherin were also noted. SIGNIFICANCE Taken together, these findings suggest that changes in the non-neuronal cholinergic system may contribute to alterations in cell-cell contacts and possibly communication with underlying cells that may contribute to changes in sensory function and visceral hyperalgesia in functional esophageal pain.
Collapse
Affiliation(s)
- Amanda S Wolf-Johnston
- University of Pittsburgh School of Medicine, Department of Medicine, Pittsburgh, PA 15261, USA
| | | | | | | | | | | | | |
Collapse
|
46
|
Chaudhury A, He XD, Goyal RK. Role of myosin Va in purinergic vesicular neurotransmission in the gut. Am J Physiol Gastrointest Liver Physiol 2012; 302:G598-607. [PMID: 22207579 PMCID: PMC3311306 DOI: 10.1152/ajpgi.00330.2011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We examined the hypothesis that myosin Va, by transporting purinergic vesicles to the varicosity membrane for exocytosis, plays a key role in purinergic vesicular neurotransmission. Studies were performed in wild-type (WT) and myosin Va-deficient dilute, brown, nonagouti (DBA) mice. Intracellular microelectrode recordings were made in mouse antral muscle strips. Purinergic inhibitory junction potential (pIJP) was recorded under nonadrenergic noncholinergic conditions after masking the nitrergic junction potentials. DBA mice showed reduced pIJP but normal hyperpolarizing response to P2Y1 receptor agonist MRS-2365. To investigate the mechanism of reduced purinergic transmission in DBA mice, studies were performed in isolated varicosities obtained from homogenates of whole gut tissues by ultracentrifugation and sucrose cushion purification. Purinergic varicosities were identified in tissue sections and in isolated varicosities by immunostaining for the vesicular ATP transporter, the solute carrier protein SLC17A9. The varicosities were similar in WT and DBA mice. Myosin Va was markedly reduced in DBA varicosities compared with the WT varicosities. Proximity ligation assay showed that myosin Va was closely associated with SLC17A9. Vesicular exoendocytosis was examined by FM1-43 staining of varicosities, which showed that exoendocytosis after KCl stimulation was impaired in DBA varicosities compared with WT varicosities. These studies show that SLC17A9 identifies ATP-containing purinergic varicosities. Myosin Va associates with SLC17A9-stained vesicles and possibly transports them to varicosity membrane for exocytosis. In myosin Va-deficient mice, purinergic inhibitory neurotransmission is impaired.
Collapse
Affiliation(s)
- Arun Chaudhury
- Center for Swallowing & Motility Disorders, Veterans Affairs Boston HealthCare System and Harvard Medical School, Boston, Massachusetts
| | - Xue-Dao He
- Center for Swallowing & Motility Disorders, Veterans Affairs Boston HealthCare System and Harvard Medical School, Boston, Massachusetts
| | - Raj K. Goyal
- Center for Swallowing & Motility Disorders, Veterans Affairs Boston HealthCare System and Harvard Medical School, Boston, Massachusetts
| |
Collapse
|
47
|
Durnin L, Hwang SJ, Ward SM, Sanders KM, Mutafova-Yambolieva VN. Adenosine 5-diphosphate-ribose is a neural regulator in primate and murine large intestine along with β-NAD(+). J Physiol 2012; 590:1921-41. [PMID: 22351627 DOI: 10.1113/jphysiol.2011.222414] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Adenosine 5′-triphosphate (ATP) has long been considered to be the purine inhibitory neurotransmitter in gastrointestinal (GI) muscles, but recent studies indicate that another purine nucleotide, β-nicotinamide adenine dinucleotide (β-NAD(+)), meets pre- and postsynaptic criteria for a neurotransmitter better than ATP in primate and murine colons. Using a small-volume superfusion assay and HPLC with fluorescence detection and intracellular microelectrode techniques we compared β-NAD(+) and ATP metabolism and postjunctional effects of the primary extracellular metabolites of β-NAD(+) and ATP, namely ADP-ribose (ADPR) and ADP in colonic muscles from cynomolgus monkeys and wild-type (CD38(+/+)) and CD38(−/−) mice. ADPR and ADP caused membrane hyperpolarization that, like nerve-evoked inhibitory junctional potentials (IJPs), were inhibited by apamin. IJPs and hyperpolarization responses to ADPR, but not ADP, were inhibited by the P2Y1 receptor antagonist (1R,2S,4S,5S)-4-[2-iodo-6-(methylamino)-9H-purin-9-yl]-2-(phosphonooxy)bicyclo[3.1.0]hexane-1-methanol dihydrogen phosphate ester tetraammonium salt (MRS2500). Degradation of β-NAD(+) and ADPR was greater per unit mass in muscles containing only nerve processes than in muscles also containing myenteric ganglia. Thus, mechanisms for generation of ADPR from β-NAD(+) and for termination of the action of ADPR are likely to be present near sites of neurotransmitter release. Degradation of β-NAD(+) to ADPR and other metabolites appears to be mediated by pathways besides CD38, the main NAD-glycohydrolase in mammals. Degradation of β-NAD(+) and ATP were equal in colon. ADPR like its precursor, β-NAD(+), mimicked the effects of the endogenous purine neurotransmitter in primate and murine colons. Taken together, our observations support a novel hypothesis in which multiple purines contribute to enteric inhibitory regulation of gastrointestinal motility.
Collapse
Affiliation(s)
- Leonie Durnin
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV 89557-0575, USA
| | | | | | | | | |
Collapse
|
48
|
García-Alcocer G, Padilla K, Rodríguez A, Miledi R, Berumen LC. Distribution of the purinegic receptors P2X4 and P2X6 during rat gut development. Neurosci Lett 2012; 509:92-5. [DOI: 10.1016/j.neulet.2011.12.044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 11/01/2011] [Accepted: 12/22/2011] [Indexed: 11/25/2022]
|
49
|
Meng E, Young JS, Cha TL, Sun GH, Yu DS, Brading AF. Neuronal-derived nitric oxide modulates the activity of mouse detrusor smooth muscle. Neurourol Urodyn 2012; 31:572-8. [PMID: 22275213 DOI: 10.1002/nau.21247] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2011] [Accepted: 11/07/2011] [Indexed: 11/10/2022]
Abstract
AIMS We investigated the roles of neuronal-derived nitric oxide (NO) in the modulation of spontaneous activity of mouse detrusor smooth muscle. METHODS Detrusor smooth muscle strips were isolated from nNOS gene knock-out (nNOS(-/-) ) mice and their wild type siblings (nNOS(+/+) ). The properties of smooth muscle cells were assessed using intracellular electrophysiology and Ca(2+) imaging by laser-scanning confocal microscopy. The effects of an nNOS inhibitor, 7-nitro indazole (7-NI) on electrically evoked contractility were assessed using nNOS(+/+) mouse detrusor strips. RESULTS In spontaneously active cells, the frequency of spontaneous action potentials (sAPs) and whole cell Ca(2+) flashes in nNOS(-/-) preparations was lower than that in the nNOS(+/+) preparations. The frequency of sAPs was enhanced by a nitric oxide donor, diethylamine NONOate sodium salt (NONOate; 100 µM), both when used alone and when the cGMP pathway was blocked by 1H-[1,2,4] oxadiazolo [4,3-a] quinoxalin-1-one (ODQ, 10 µM). 7-NI (100 µM) significantly suppressed the electrically evoked contraction of mouse detrusor strips. CONCLUSIONS We suggest that neuronal-derived NO facilitates the generation of spontaneous activity via a cGMP-independent pathway, and consequently enhances the evoked contraction of detrusor. Dysregulation of nNOS containing nerves may underlie bladder pathologies.
Collapse
Affiliation(s)
- E Meng
- Department of Surgery, National Defense Medical Center, Taipei, Taiwan, Republic of China.
| | | | | | | | | | | |
Collapse
|
50
|
Domènech A, Pasquinelli G, De Giorgio R, Gori A, Bosch F, Pumarola M, Jiménez M. Morphofunctional changes underlying intestinal dysmotility in diabetic RIP-I/hIFNβ transgenic mice. Int J Exp Pathol 2011; 92:400-12. [PMID: 22050417 DOI: 10.1111/j.1365-2613.2011.00789.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The pathogenetic mechanisms underlying gastrointestinal dysmotility in diabetic patients remain poorly understood, although enteric neuropathy, damage to interstitial cells of Cajal (ICC) and smooth muscle cell injury are believed to play a role. The aim of this study was to investigate the morphological and functional changes underlying intestinal dysmotility in RIP-I/hIFNβ transgenic mice treated with multiple very low doses of streptozotocin (20 mg/kg, i.p., 5 days). Compared with vehicle-treated mice, streptozotocin-treated animals developed type 1 diabetes mellitus, with sustained hyperglycaemia for 3.5 months, polyphagia, polydipsia and increased faecal output without changes in faecal water content (metabolic cages). Diabetic mice had a longer intestine, longer ileal villi and wider colonic crypts (conventional microscopy) and displayed faster gastric emptying and intestinal transit. Contractility studies showed selective impaired neurotransmission in the ileum and mid-colon of diabetic mice. Compared with controls, the ileal and colonic myenteric plexus of diabetic mice revealed ultrastructural features of neuronal degeneration and HuD immunohistochemistry on whole-mount preparations showed 15% reduction in neuronal numbers. However, no immunohistochemical changes in apoptosis-related markers were noted. Lower absolute numbers of neuronal nitric oxide synthase- and choline acetyltransferase-immunopositive neurons and enhanced vasoactive intestinal polypeptide and substance P immunopositivity were observed. Ultrastructural and immunohistochemical analyses did not reveal changes in the enteric glial or ICC networks. In conclusion, this model of diabetic enteropathy shows enhanced intestinal transit associated with intestinal remodelling, including neuroplastic changes, and overt myenteric neuropathy. Such abnormalities are likely to reflect neuroadaptive and neuropathological changes occurring in this diabetic model.
Collapse
Affiliation(s)
- Anna Domènech
- Department of Animal Medicine and Surgery, Universitat Autònoma de Barcelona, Bellaterra, Spain.
| | | | | | | | | | | | | |
Collapse
|