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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.
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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.)
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Zhao Y, Luo H, Ren X, Jia B, Li J, Wang L, Li J. The P2Y 1 receptor in the colonic myenteric plexus of rats and its correlation with opioid-induced constipation. BMC Gastroenterol 2024; 24:23. [PMID: 38191294 PMCID: PMC10773096 DOI: 10.1186/s12876-024-03119-9] [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: 08/14/2023] [Accepted: 01/01/2024] [Indexed: 01/10/2024] Open
Abstract
This study was designed to explore the expression changes of P2Y1 receptors in the distal colonic myenteric layer of rats. An opioid induced constipation(OIC) rat model was generated by intraperitoneal (i.p) injection of loperamide. At 7 days post-treatment, the model rats were assessed by calculating the fecal water content and the gastrointestinal transit ratio. The immunofluorescence (IF)-based histochemical study was used to observe the distribution of P2Y1 receptors in the distal colonic myenteric plexus. Western blotting (WB) was performed to evaluate the expression changes of P2Y1 proteins in the myenteric layer, and the electrophysiological approaches were carried out to determine the regulatory roles of P2Y1 receptors on distal colonic motor function. IF showed that P2Y1 receptors are co-expressed MOR in the enteric nerve cells of the distal colonic myenteric plexus. Moreover, the WB revealed that the protein levels of P2Y1 were significantly decreased in the distal colonic myenteric layer of OIC rats. In vitro tension experiments exhibited that the P2Y1 receptor antagonist MRS2500 enhanced the spontaneous contraction amplitude, adding EM2 and β-FNA did not have any effect on MRS2500. Therefore, P2Y1 receptor expression could be associated with the occurrence of OIC in this rat model and the regulation of colonic motility by MOR may be related to the release of purine neurotransmitters such as ATP in the colonic nervous system.
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Affiliation(s)
- Yuqiong Zhao
- Department of Human Anatomy and Histoembryology, College of Basic Medical Sciences, Ningxia Medical University, 1160 Shengli Street, 750001, Yinchuan, Ningxia Hui Autonomous Region, P.R. China
| | - Huijuan Luo
- Department of Human Anatomy and Histoembryology, College of Basic Medical Sciences, Ningxia Medical University, 1160 Shengli Street, 750001, Yinchuan, Ningxia Hui Autonomous Region, P.R. China
| | - Xiaojie Ren
- Department of Human Anatomy and Histoembryology, College of Basic Medical Sciences, Ningxia Medical University, 1160 Shengli Street, 750001, Yinchuan, Ningxia Hui Autonomous Region, P.R. China
| | - Binghan Jia
- Department of Human Anatomy and Histoembryology, College of Basic Medical Sciences, Ningxia Medical University, 1160 Shengli Street, 750001, Yinchuan, Ningxia Hui Autonomous Region, P.R. China
| | - Jinzhao Li
- Department of Human Anatomy and Histoembryology, College of Basic Medical Sciences, Ningxia Medical University, 1160 Shengli Street, 750001, Yinchuan, Ningxia Hui Autonomous Region, P.R. China
| | - Lixin Wang
- The Medical Laboratory Center of General Hospital of Ningxia Medical University, 804 Shengli Street, 750001, Yinchuan, Ningxia Hui Autonomous Region, P.R. China.
| | - Junping Li
- Department of Human Anatomy and Histoembryology, College of Basic Medical Sciences, Ningxia Medical University, 1160 Shengli Street, 750001, Yinchuan, Ningxia Hui Autonomous Region, P.R. China.
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Jooss T, Zhang J, Zimmer B, Rezzonico-Jost T, Rissiek B, Felipe Pelczar P, Seehusen F, Koch-Nolte F, Magnus T, Zierler S, Huber S, Schemann M, Grassi F, Nicke A. Macrophages and glia are the dominant P2X7-expressing cell types in the gut nervous system-No evidence for the role of neuronal P2X7 receptors in colitis. Mucosal Immunol 2023; 16:180-193. [PMID: 36634819 DOI: 10.1016/j.mucimm.2022.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 11/29/2022] [Indexed: 01/11/2023]
Abstract
The blockade or deletion of the pro-inflammatory P2X7 receptor channel has been shown to reduce tissue damage and symptoms in models of inflammatory bowel disease, and P2X7 receptors on enteric neurons were suggested to mediate neuronal death and associated motility changes. Here, we used P2X7-specific antibodies and nanobodies, as well as a bacterial artificial chromosome transgenic P2X7-EGFP reporter mouse model and P2rx7-/- controls to perform a detailed analysis of cell type-specific P2X7 expression and possible overexpression effects in the enteric nervous system of the distal colon. In contrast to previous studies, we did not detect P2X7 in neurons but found dominant expression in glia and macrophages, which closely interact with the neurons. The overexpression of P2X7 per se did not induce significant pathological effects. Our data indicate that macrophages and/or glia account for P2X7-mediated neuronal damage in inflammatory bowel disease and provide a refined basis for the exploration of P2X7-based therapeutic strategies.
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Affiliation(s)
- Tina Jooss
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig Maximilian University, Munich, Germany
| | - Jiong Zhang
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig Maximilian University, Munich, Germany
| | - Béla Zimmer
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig Maximilian University, Munich, Germany
| | - Tanja Rezzonico-Jost
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - Björn Rissiek
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | - Frauke Seehusen
- Laboratory for Animal Model Pathology (LAMP), Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Friedrich Koch-Nolte
- Institute of Immunology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tim Magnus
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Susanna Zierler
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig Maximilian University, Munich, Germany; Institute of Pharmacology, Medical Faculty, Johannes Kepler University Linz, Linz, Austria
| | - Samuel Huber
- Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Michael Schemann
- Human Biology, Technical University Munich, Freising-Weihenstephan, Germany
| | - Fabio Grassi
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - Annette Nicke
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig Maximilian University, Munich, Germany.
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Zhao Y, Ren X, Li F, Jia B, Wang D, Jia H, Jiao X, Wang L, Li J. P2Y1 receptor in the colonic submucosa of rats and its association with opioid‑induced constipation. Exp Ther Med 2022; 25:67. [PMID: 36605532 PMCID: PMC9798462 DOI: 10.3892/etm.2022.11766] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 11/03/2022] [Indexed: 12/15/2022] Open
Abstract
The aim of the present study was to explore the expression changes of P2Y purinergic receptor 1 (P2Y1) in the distal colonic submucosa of opioid-induced constipation (OIC) rats and its association with the occurrence of OIC, an OIC rat model was generated by intraperitoneal injection of loperamide hydrochloride, a selective agonist of µ-opioid receptors (MORs). At 7 days post-treatment, the model was assessed by analyzing stool scores and calculating the gastrointestinal (GI) transit ratio of rats. The distribution of P2Y1-expressing neurons in the colonic submucosal plexus was demonstrated by immunofluorescence (IF). Western blotting was performed to evaluate the expression changes of MOR, P2Y1 and ATP synthase subunit β (ATPB) proteins in the colonic submucosa, while reverse transcription-quantitative PCR (RT-qPCR) analysis was performed to determine the relative mRNA expression of MOR and P2Y1. After 7 days, the feces of OIC rats exhibited an appearance of sausage-shaped pieces and both the stool weight and GI transit ratio of OIC rats were significantly decreased. IF revealed co-expression of P2Y1 and calbindin and MOR and ATPB in the nerve cells of the distal colonic submucosal plexus. Moreover, RT-qPCR analysis showed that the MOR mRNA levels were significantly increased in the distal colonic submucosa of OIC rats, while mRNA levels of P2Y1 were decreased. WB showed that in the distal colonic submucosa of OIC rats, MOR protein expression was increased, whereas that of P2Y1 was significantly decreased. GI transit ratio analysis suggested that the P2Y agonist ATP significantly relieved constipation symptoms in rats, while the P2Y inhibitor MRS2179 aggravated these symptoms. Finally, P2Y1 expression change was shown to be associated with the occurrence of OIC, while expression of MOR and P2Y1 was associated with OIC development in rats.
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Affiliation(s)
- Yuqiong Zhao
- Department of Human Anatomy and Histoembryology, College of Basic Medical Sciences, Ningxia Medical University, Yinchuan, Ningxia Hui Autonomous Region 750001, P.R. China
| | - Xiaojie Ren
- Department of Human Anatomy and Histoembryology, College of Basic Medical Sciences, Ningxia Medical University, Yinchuan, Ningxia Hui Autonomous Region 750001, P.R. China
| | - Fan Li
- Department of Gastrointestinal Surgery, Xiantao First People's Hospital Affiliated to Yangtze University, Xiantao, Hubei 433000, P.R. China
| | - Binghan Jia
- Department of Human Anatomy and Histoembryology, College of Basic Medical Sciences, Ningxia Medical University, Yinchuan, Ningxia Hui Autonomous Region 750001, P.R. China
| | - Dengke Wang
- Department of Human Anatomy and Histoembryology, College of Basic Medical Sciences, Ningxia Medical University, Yinchuan, Ningxia Hui Autonomous Region 750001, P.R. China
| | - Hua Jia
- Department of Human Anatomy and Histoembryology, College of Basic Medical Sciences, Ningxia Medical University, Yinchuan, Ningxia Hui Autonomous Region 750001, P.R. China
| | - Xuwen Jiao
- Department of Human Anatomy and Histoembryology, College of Basic Medical Sciences, Ningxia Medical University, Yinchuan, Ningxia Hui Autonomous Region 750001, P.R. China
| | - Lixin Wang
- The Medical Laboratory Center of General Hospital of Ningxia Medical University, Yinchuan, Ningxia Hui Autonomous Region 750001, P.R. China,Correspondence to: Dr Junping Li, Department of Human Anatomy and Histoembryology, College of Basic Medical Sciences, Ningxia Medical University, 1160 Shengli Street, Yinchuan, Ningxia Hui Autonomous Region 750001, P.R. China
| | - Junping Li
- Department of Human Anatomy and Histoembryology, College of Basic Medical Sciences, Ningxia Medical University, Yinchuan, Ningxia Hui Autonomous Region 750001, P.R. China,Correspondence to: Dr Junping Li, Department of Human Anatomy and Histoembryology, College of Basic Medical Sciences, Ningxia Medical University, 1160 Shengli Street, Yinchuan, Ningxia Hui Autonomous Region 750001, P.R. China
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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.
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Affiliation(s)
- Brian F King
- University College London (UCL), Research Department of Neuroscience, Pharmacology & Physiology (NPP), Gower Street, London WC1E 6BT, United Kingdom.
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Yamato S, Kurematsu A, Amano T, Ariga H, Ando T, Komaki G, Wada K. Urocortin 1: A putative excitatory neurotransmitter in the enteric nervous system. Neurogastroenterol Motil 2020; 32:e13842. [PMID: 32196844 DOI: 10.1111/nmo.13842] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 02/24/2020] [Accepted: 03/03/2020] [Indexed: 12/20/2022]
Abstract
BACKGROUND Urocortin 1 (Ucn1), a stress-related peptide, is a member of the corticotropin-releasing factor (CRF) family and acts as a CRF1 receptor agonist. Ucn1 and CRF1 receptor immunoreactivity are present in the enteric nervous system (ENS), and Ucn1 elicits contraction of colonic muscle strips. Considering these findings, we have hypothesized that Ucn1 acts as an excitatory neurotransmitter in the ENS. The present study was conducted to determine whether exogenously applied Ucn1 causes contractions, whether it participates in neurally mediated contraction, and whether it is released from the ENS of the rat colon. METHODS Isometric tension of the rat colonic muscle strips (middle to distal colon) in a longitudinal direction was measured. The effects of Ucn1 on phasic contractions were examined in the absence and presence of antalarmin (CRF1 receptor antagonist), tetrodotoxin (TTX), and atropine. The effects of antalarmin on electrical field stimulation (EFS)-induced contractions were examined in the absence and presence of atropine. Ucn1 peptide in the bath solution was measured after EFS using an EIA kit. KEY RESULTS Ucn1 caused a significant and dose-dependent increase in phasic contractions. These effects were completely inhibited by antalarmin, TTX, and atropine. EFS-induced contractions were inhibited by antalarmin. Atropine markedly reduced EFS-induced contractions, and antalarmin did not decrease these contractions further. EFS elicited a significant increase in the concentration of Ucn1 in the bath solution, and this increase was completely inhibited by TTX. CONCLUSIONS AND INFERENCES These results suggest that Ucn1 acts as an excitatory neurotransmitter in the ENS enhancing the cholinergic neurotransmission.
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Affiliation(s)
- Shigeru Yamato
- Department of Gastroenterology, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Ayako Kurematsu
- Department of Gastroenterology, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Tomofumi Amano
- Department of Gastroenterology, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Hajime Ariga
- Department of Gastroenterology, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Tetsuya Ando
- Department of Psychosomatic Research, National Institute of Mental Health, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Gen Komaki
- Department of Psychosomatic Research, National Institute of Mental Health, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Keiji Wada
- Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
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Abstract
Purinergic signaling was proposed in 1972, after it was demonstrated that adenosine 5'-triphosphate (ATP) was a transmitter in nonadrenergic, noncholinergic inhibitory nerves supplying the guinea-pig taenia coli. Later, ATP was identified as an excitatory cotransmitter in sympathetic and parasympathetic nerves, and it is now apparent that ATP acts as a cotransmitter in most, if not all, nerves in both the peripheral nervous system and central nervous system (CNS). ATP acts as a short-term signaling molecule in neurotransmission, neuromodulation, and neurosecretion. It also has potent, long-term (trophic) roles in cell proliferation, differentiation, and death in development and regeneration. Receptors to purines and pyrimidines have been cloned and characterized: P1 adenosine receptors (with four subtypes), P2X ionotropic nucleotide receptors (seven subtypes) and P2Y metabotropic nucleotide receptors (eight subtypes). ATP is released from different cell types by mechanical deformation, and after release, it is rapidly broken down by ectonucleotidases. Purinergic receptors were expressed early in evolution and are widely distributed on many different nonneuronal cell types as well as neurons. Purinergic signaling is involved in embryonic development and in the activities of stem cells. There is a growing understanding about the pathophysiology of purinergic signaling and there are therapeutic developments for a variety of diseases, including stroke and thrombosis, osteoporosis, pain, chronic cough, kidney failure, bladder incontinence, cystic fibrosis, dry eye, cancer, and disorders of the CNS, including Alzheimer's, Parkinson's. and Huntington's disease, multiple sclerosis, epilepsy, migraine, and neuropsychiatric and mood disorders.
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Mendes CE, Palombit K, Tavares-de-Lima W, Castelucci P. Enteric glial cells immunoreactive for P2X7 receptor are affected in the ileum following ischemia and reperfusion. Acta Histochem 2019; 121:665-679. [PMID: 31202513 DOI: 10.1016/j.acthis.2019.06.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 05/31/2019] [Accepted: 06/03/2019] [Indexed: 12/21/2022]
Abstract
The aim of this study was to analyze the effect of ischemia and reperfusion injury (IS) on enteric glial cells (EGCs) and neurons immunoreactive for the P2X7 receptor. Intestinal ischemia was induced by obstructing blood flow in the ileal vessels for 35 min. Afterwards, the vessels were reperfused for 14 days. Tissues were prepared for immunohistochemical labeling of P2X7 receptor, HuC/D (Hu) (pan-neuronal marker) and S100β (glial marker); HuC/D (Hu) and glial fibrillary acidic protein (GFAP, glial marker)/DAPI (nuclear marker); or S100β and GFAP/DAPI. Qualitative and quantitative analyses of colocalization, density, profile area and cell proliferation were performed via fluorescence and confocal laser scanning microscopy. The quantitative analyses revealed that a) neurons and EGCs were immunoreactive for P2X7 receptor; b) the P2X7 receptor immunoreactive cells and Hu immunoreactive neurons were reduced after 0 h and 14 days of reperfusion; c) the S100β and GFAP immunoreactive EGCs were increased; d) the profile area of S100β immunoreactive EGCs was increased by IS; e) few GFAP immunoreactive proliferated at 14 days of reperfusion; f) distinct populations of glial cells can be discerned: S100β+/GFAP+ cells, S100β+/GFAP- cells and S100β-/GFAP + cells; g) histological analysis revealed less alterations in the epithelium cells in the IS groups and h) myeloperoxidase reaction revealed increased of the neutrophils in the lamina propria in the IS groups. This study showed that IS is associated with significant neuronal loss, increase of glial cells and altered purinergic receptor expression and that these changes may contribute to intestinal disorders.
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Safety and Efficacy of Ferula asafoetida in Functional Dyspepsia: A Randomized, Double-Blinded, Placebo-Controlled Study. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2018; 2018:4813601. [PMID: 30224930 PMCID: PMC6129344 DOI: 10.1155/2018/4813601] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 07/04/2018] [Accepted: 08/02/2018] [Indexed: 12/14/2022]
Abstract
Despite the availability of various synthetic drugs for the treatment of functional dyspepsia (FD), the side effects and their cost have always created a great interest in the search for novel natural alternatives for the management of gut disorders. The present contribution reports the safety and efficacy of the kitchen spice asafoetida (Ferula asafoetida) in FD for the first time. In the double-blinded, placebo-controlled study, 43 subjects diagnosed to have moderate to severe discomforts of nonulcer FD were randomized to receive hard-shell capsules (250 mg × 2/day) of either placebo (n=22) or a food-grade formulation of asafoetida (Asafin) (n=21) for 30 days. When evaluated by a set of validated indexing tools (GSRS, GDSS, and NDI), almost 81% in the Asafin group showed significant (p < 0.01) improvement in the overall score and quality of life as compared to the placebo. At the end of the study, 66% of subjects in the Asafin group remained symptoms-free. Although the symptoms score improved significantly in both the groups (from -5.67 to -25.29 in Asafin group versus -1.55 to -6.0 in the placebo; p ≤ 0.001), the relative percentage of subjects in the Asafin group with more than 80% reduction in various symptoms were: bloating (58%), appetite (69%), postprandial fullness (74%) motion sickness (75%), and digestion (77%) as compared to less than 10% nonspecific improvement in the placebo group. All the subjects remained safe with no adverse events or variations in haematological and biochemical parameters. The study was registered at http://ctri.nic.in/ (CTRI/2018/ 01/011149).
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Ji R, Zhu J, Wang D, Sui QQ, Knight GE, Burnstock G, Yuan H, Xiang Z. Expression of P2X1 receptors in somatostatin-containing cells in mouse gastrointestinal tract and pancreatic islets of both mouse and human. Purinergic Signal 2018; 14:285-298. [PMID: 29974392 DOI: 10.1007/s11302-018-9615-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 06/07/2018] [Indexed: 12/19/2022] Open
Abstract
With immunohistochemical and Western blot techniques, P2X1 receptors were detected in the whole mouse gastrointestinal tract and pancreatic islets of mouse and human. (1) δ Cells containing somatostatin (SOM) in the stomach corpus, small intestines, distal colon, pancreatic islets of both mouse and human express P2X1 receptors; (2) strong immunofluorescence of P2X1 receptors was detected in smooth muscle fibers and capillary networks of the villus core of mouse intestine; and (3) P2X1 receptor-immunoreactive neurons were also detected widely in both mouse myenteric and submucosal plexuses, all of which express SOM. The present data implies that ATP via P2X1 receptors is involved in SOM release from pancreatic δ cells, enteric neurons, and capillary networks in villi.
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Affiliation(s)
- Ruihua Ji
- Department of Anesthesiology, Changzheng Hospital, Second Military Medical University, Shanghai, 200003, China
| | - Jiao Zhu
- Department of Neurobiology, MOE Key Laboratory of Molecular Neurobiology, Ministry of Education, Neuroscience Research Centre of Changzheng Hospital, Second Military Medical University, Shanghai, 200433, People's Republic of China
| | - Dan Wang
- Department of Neurobiology, MOE Key Laboratory of Molecular Neurobiology, Ministry of Education, Neuroscience Research Centre of Changzheng Hospital, Second Military Medical University, Shanghai, 200433, People's Republic of China
| | - Qian-Qian Sui
- Department of Neurobiology, MOE Key Laboratory of Molecular Neurobiology, Ministry of Education, Neuroscience Research Centre of Changzheng Hospital, Second Military Medical University, Shanghai, 200433, People's Republic of China
| | - Gillian E Knight
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF, UK
| | - Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF, UK
- Department of Pharmacology, Melbourne University, Melbourne, Australia
- Florey Institute of Neuroscience and Mental Health, Parkville, Melbourne, Australia
| | - Hongbin Yuan
- Department of Anesthesiology, Changzheng Hospital, Second Military Medical University, Shanghai, 200003, China.
| | - Zhenghua Xiang
- Department of Neurobiology, MOE Key Laboratory of Molecular Neurobiology, Ministry of Education, Neuroscience Research Centre of Changzheng Hospital, Second Military Medical University, Shanghai, 200433, People's Republic of China.
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Bhave S, Gade A, Kang M, Hauser KF, Dewey WL, Akbarali HI. Connexin-purinergic signaling in enteric glia mediates the prolonged effect of morphine on constipation. FASEB J 2017; 31:2649-2660. [PMID: 28280004 DOI: 10.1096/fj.201601068r] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 02/21/2017] [Indexed: 01/20/2023]
Abstract
Morphine is one of the most widely used drugs for the treatment of pain. However, side effects, including persistent constipation and antinociceptive tolerance, limit its clinical efficacy. Prolonged morphine treatment results in a "leaky" gut, predisposing to colonic inflammation that is facilitated by microbial dysbiosis and associated bacterial translocation. In this study, we examined the role of enteric glia in mediating this secondary inflammatory response to prolonged treatment with morphine. We found that purinergic P2X receptor activity was significantly enhanced in enteric glia that were isolated from mice with long-term morphine treatment (in vivo) but not upon direct exposure of glia to morphine (in vitro). LPS, a major bacterial product, also increased ATP-induced currents, as well as expression of P2X4, P2X7, IL6, IL-1β mRNA in enteric glia. LPS increased connexin43 (Cx43) expression and enhanced ATP release from enteric glia cells. LPS-induced P2X currents and proinflammatory cytokine mRNA expression were blocked by the Cx43 blockers Gap26 and carbenoxolone. Likewise, colonic inflammation related to prolonged exposure to morphine was significantly attenuated by carbenoxolone (25 mg/kg). Carbenoxolone also prevented gut wall disruption and significantly reduced morphine-induced constipation. These findings imply that enteric glia activation is a significant modulator of morphine-related inflammation and constipation.-Bhave, S., Gade, A., Kang, M., Hauser, K. F., Dewey, W. L., Akbarali, H. I. Connexin-purinergic signaling in enteric glia mediates the prolonged effect of morphine on constipation.
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Affiliation(s)
- Sukhada Bhave
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Aravind Gade
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Minho Kang
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Kurt F Hauser
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - William L Dewey
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Hamid I Akbarali
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, USA
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12
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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.
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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.
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Deiteren A, van der Linden L, de Wit A, Ceuleers H, Buckinx R, Timmermans JP, Moreels TG, Pelckmans PA, De Man JG, De Winter BY. P2X3 receptors mediate visceral hypersensitivity during acute chemically-induced colitis and in the post-inflammatory phase via different mechanisms of sensitization. PLoS One 2015; 10:e0123810. [PMID: 25885345 PMCID: PMC4401691 DOI: 10.1371/journal.pone.0123810] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 03/07/2015] [Indexed: 01/08/2023] Open
Abstract
Objectives Experiments using P2X3 knock-out mice or more general P2X receptor antagonists suggest that P2X3 receptors contribute to visceral hypersensitivity. We aimed to investigate the effect of the selective P2X3 antagonist A-317491 on visceral sensitivity under physiological conditions, during acute colitis and in the post-inflammatory phase of colitis. Methods Trinitrobenzene sulphonic-acid colitis was monitored by colonoscopy: on day 3 to confirm the presence of colitis and then every 4 days, starting from day 10, to monitor convalescence and determine the exact timepoint of endoscopic healing in each rat. Visceral sensitivity was assessed by quantifying visceromotor responses to colorectal distension in controls, rats with acute colitis and post-colitis rats. A-317491 was administered 30 min prior to visceral sensitivity testing. Expression of P2X3 receptors (RT-PCR and immunohistochemistry) and the intracellular signalling molecules cdk5, csk and CASK (RT-PCR) were quantified in colonic tissue and dorsal root ganglia. ATP release in response to colorectal distension was measured by luminiscence. Results Rats with acute TNBS-colitis displayed significant visceral hypersensitivity that was dose-dependently, but not fully, reversed by A-317491. Hypersenstivity was accompanied by an increased colonic release of ATP. Post-colitis rats also displayed visceral hypersensitivity that was dose-dependently reduced and fully normalized by A-317491 without increased release of ATP. A-317491 did not modify visceral sensitivity in controls. P2X3 mRNA and protein expression in the colon and dorsal root ganglia were similar in control, acute colitis and post-colitis groups, while colonic mRNA expression of cdk5, csk and CASK was increased in the post-colitis group only. Conclusions These findings indicate that P2X3 receptors are not involved in sensory signaling under physiological conditions whereas they modulate visceral hypersensitivity during acute TNBS-colitis and even more so in the post-inflammatory phase, albeit via different mechanisms of sensitization, validating P2X3 receptors as potential new targets in the treatment of abdominal pain syndromes.
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Affiliation(s)
- Annemie Deiteren
- Laboratory of Experimental Medicine and Pediatrics, Division of Gastroenterology, University of Antwerp, Antwerp, Belgium
| | - Laura van der Linden
- Laboratory of Experimental Medicine and Pediatrics, Division of Gastroenterology, University of Antwerp, Antwerp, Belgium
| | - Anouk de Wit
- Laboratory of Experimental Medicine and Pediatrics, Division of Gastroenterology, University of Antwerp, Antwerp, Belgium
| | - Hannah Ceuleers
- Laboratory of Experimental Medicine and Pediatrics, Division of Gastroenterology, University of Antwerp, Antwerp, Belgium
| | - Roeland Buckinx
- Laboratory of Cell Biology and Histology, University of Antwerp, Antwerp, Belgium
| | | | - Tom G. Moreels
- Laboratory of Experimental Medicine and Pediatrics, Division of Gastroenterology, University of Antwerp, Antwerp, Belgium
- Antwerp University Hospital, Department of Gastroenterology and Hepatology, Antwerp, Belgium
| | - Paul A. Pelckmans
- Laboratory of Experimental Medicine and Pediatrics, Division of Gastroenterology, University of Antwerp, Antwerp, Belgium
- Antwerp University Hospital, Department of Gastroenterology and Hepatology, Antwerp, Belgium
| | - Joris G. De Man
- Laboratory of Experimental Medicine and Pediatrics, Division of Gastroenterology, University of Antwerp, Antwerp, Belgium
| | - Benedicte Y. De Winter
- Laboratory of Experimental Medicine and Pediatrics, Division of Gastroenterology, University of Antwerp, Antwerp, Belgium
- * E-mail:
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Hejazian SH, Bagheri SM, Safari F. Spasmolytic and Anti-Spasmodic Action of Trachyspermum ammi Essence on Rat's Ileum Contraction. NORTH AMERICAN JOURNAL OF MEDICAL SCIENCES 2015; 6:643-7. [PMID: 25599053 PMCID: PMC4290054 DOI: 10.4103/1947-2714.147982] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Background: Trachyspermum ammi is a plant of umbelliferae family and has been traditionally used in the treatment of many gastrointestinal disorders such as indigestion, colic, and diarrhea. Our previous study demonstrated that aqueous extract of Trachyspermum ammi reduced the contractile activity of rat's ileum. Aims: This study was designed to examine the effect of Trachyspermum ammi essence on acetylcholine-induced contraction in isolated rat's ileum. Materials and Methods: In this experimental procedure, the tissue samples were suspended from the transducer lever and mounted on the organ bath containing Tyrode's solution. Isotonic responses were recorded by using an isotonic transducer and the amplitude of contractions. This process was induced by cumulative logarithmic concentrations of acetylcholine before and after exposing tissue by saline and different concentrations of essence. Results: The chemical constituents of the essence from distillate extract of Trachyspermum ammi seeds were studied by gas chromatography mass spectrometry (GC-MS) and the chemical analysis showed many components in which thymol was the main constituent. Our findings showed that the essence derived from the extract in all concentrations used in this study (0.002, 0.005, and 0.01% V/V) significantly reduced acetylcholine-induced contractions (47.34, 60.46, and 86%, respectively, P < 0.05). The same concentrations of the essence also exhibit a significant anti-spasmodic action on acetylcholine-induced contractions (0.1,88.3, and 90.7%, respectively, P < 0.05). Conclusion: Since thymol was the major constituent of our samples of Trachyspermum ammi, the relaxant effect observed in this study is probably due to this agent which can exert an anti-cholinergic property.
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Affiliation(s)
- Seyed Hassan Hejazian
- Department of Physiology/Herbal Medicine Research Center, School of Medicine, Shahid Sadoughi University of Medical Sciences and Health Services, Yazd, Iran
| | - Seyyed Majid Bagheri
- Department of Physiology, School of Medicine, Shahid Sadoughi University of Medical Sciences and Health Services, Yazd, Iran
| | - Fatemeh Safari
- Department of Physiology, School of Medicine, Shahid Sadoughi University of Medical Sciences and Health Services, Yazd, Iran
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15
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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.
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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
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16
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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.
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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.
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17
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Rau KK, Petruska JC, Cooper BY, Johnson RD. Distinct subclassification of DRG neurons innervating the distal colon and glans penis/distal urethra based on the electrophysiological current signature. J Neurophysiol 2014; 112:1392-408. [PMID: 24872531 DOI: 10.1152/jn.00560.2013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Spinal sensory neurons innervating visceral and mucocutaneous tissues have unique microanatomic distribution, peripheral modality, and physiological, pharmacological, and biophysical characteristics compared with those neurons that innervate muscle and cutaneous tissues. In previous patch-clamp electrophysiological studies, we have demonstrated that small- and medium-diameter dorsal root ganglion (DRG) neurons can be subclassified on the basis of their patterns of voltage-activated currents (VAC). These VAC-based subclasses were highly consistent in their action potential characteristics, responses to algesic compounds, immunocytochemical expression patterns, and responses to thermal stimuli. For this study, we examined the VAC of neurons retrogradely traced from the distal colon and the glans penis/distal urethra in the adult male rat. The afferent population from the distal colon contained at least two previously characterized cell types observed in somatic tissues (types 5 and 8), as well as four novel cell types (types 15, 16, 17, and 18). In the glans penis/distal urethra, two previously described cell types (types 6 and 8) and three novel cell types (types 7, 14, and 15) were identified. Other characteristics, including action potential profiles, responses to algesic compounds (acetylcholine, capsaicin, ATP, and pH 5.0 solution), and neurochemistry (expression of substance P, CGRP, neurofilament, TRPV1, TRPV2, and isolectin B4 binding) were consistent for each VAC-defined subgroup. With identification of distinct DRG cell types that innervate the distal colon and glans penis/distal urethra, future in vitro studies related to the gastrointestinal and urogenital sensory function in normal as well as abnormal/pathological conditions may be benefitted.
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Affiliation(s)
- Kristofer K Rau
- Department of Anesthesiology, Department of Anatomical Sciences and Neurobiology, and Kentucky Spinal Cord Injury Research Center, University of Louisville College of Medicine, Louisville, Kentucky; Department of Physiological Sciences, University of Florida College of Veterinary Medicine and McKnight Brain Institute, Gainesville, Florida
| | - Jeffrey C Petruska
- Department of Anatomical Sciences and Neurobiology, Department of Neurological Surgery, Kentucky Spinal Cord Injury Research Center, University of Louisville College of Medicine, Louisville, Kentucky
| | - Brian Y Cooper
- Department of Oral and Maxillofacial Surgery, Division of Neuroscience, J. Hillis Miller Health Center, University of Florida College of Dentistry and McKnight Brain Institute, Gainesville, Florida; and
| | - Richard D Johnson
- Department of Physiological Sciences, University of Florida College of Veterinary Medicine and McKnight Brain Institute, Gainesville, Florida
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18
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Bagheri S, Hejazian S, Dashti-R M. The Relaxant Effect of Seed's Essential Oil and Oleo-Gum-Resin of Ferula Assa-Foetida on Isolated Rat's Ileum. Ann Med Health Sci Res 2014; 4:238-41. [PMID: 24761245 PMCID: PMC3991947 DOI: 10.4103/2141-9248.129050] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Background: In Iranian folk medicine, several plants are used for treatment of gastrointestinal disorders, such as diarrhea and spasm. One of these herbal medications are the essential oil yielded from seeds of Ferula assa-foetida L. and an oleo-gum-resin known as asafetida, which is exudated from its root. F. assa-foetida grows wildly in south and central mountains of Iran. Aim: In this study, relaxant effect of asafoetida and seed's essential oil of F. assa-foetida was investigated in isolated rat's ileum in three doses. Materials and Methods: A total of 5 cm of ileum was removed and sets for recording its isotonic contractions. The amplitude of contractions induced by different doses of asafoetida and essential oil before and after exposing the specimens with cumulative logarithmic concentrations of acetylcholine (Ach) was evaluated. The relaxant effect of asafoetida and seed's essential oil of F. assa-foetida was investigated in isolated rat's ileum in three doses (0.1 0.2 and 0.3%). All statistical analysis was by GraphPad Prism 5 (San Diego, California) and comparisons were made by means of the analysis of variances followed by Tukey's test. The statistical significance was considered as P < 0.05. Results: Asafoetida produced an antispasmodic effect on Ach induced contraction in 0.2% and 0.3% concentrations. Our findings also showed that essential oil has significant antispasmodic action against cumulative concentrations of 10-12 up to 10-2 M Ach. In spasmolytic evaluation, our findings showed that the essential oil derived from F. assa-foetida seed in concentrations of 0.2% and 0.3% significantly reduced Ach (10-4 M) induced contractions. Exposure to the 0.2% and 0.3% asafoetida, reduced the percentage of maximum contraction induced by 10-4 M Ach to 43% and 12% respectively, which this reduction was statistically significant. Conclusion: The results of the present study, supports the traditional claim of asafoetida as an antispasmodic therapeutic.
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Affiliation(s)
- Sm Bagheri
- Department of Physiology/Herbal Medicine Research Center, Shahid Sadoghi University of Medical Sciences, Yazd, Iran
| | - Sh Hejazian
- Department of Physiology/Herbal Medicine Research Center, Shahid Sadoghi University of Medical Sciences, Yazd, Iran
| | - Mh Dashti-R
- Department of Physiology/Herbal Medicine Research Center, Shahid Sadoghi University of Medical Sciences, Yazd, Iran
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Expression of P2X3 and P2X5 Myenteric Receptors Varies During the Intestinal Postnatal Development in the Guinea Pig. Cell Mol Neurobiol 2014; 34:727-36. [DOI: 10.1007/s10571-014-0055-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 03/25/2014] [Indexed: 12/22/2022]
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20
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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.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF, UK,
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21
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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.
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Affiliation(s)
- Luca Antonioli
- Department of Clinical and Experimental Medicine, University of Pisa, Italy.
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22
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Chávez J, Vargas MH, Rebollar-Ayala DC, Díaz-Hernández V, Cruz-Valderrama JE, Flores-Soto E, Flores-García M, Jiménez-Vargas NN, Barajas-López C, Montaño LM. Inhibition of extracellular nucleotides hydrolysis intensifies the allergic bronchospasm. A novel protective role of ectonucleotidases. Allergy 2013; 68:462-71. [PMID: 23414231 DOI: 10.1111/all.12113] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/13/2012] [Indexed: 01/31/2023]
Abstract
BACKGROUND Nucleotides released to the extracellular space stimulate purinergic receptors, and their effects are modulated by ectonucleotidases. The role of ATP in the allergic bronchospasm has been scantly studied. METHODS We used several techniques (plethysmography, organ baths, confocal microscopy, RT-PCR, ATP measurement) to explore the role of nucleotides and ectonucleotidases in the allergic bronchospasm in guinea pigs. RESULTS While allergenic challenge with a low-dose ovalbumin (OVA) only produced a small bronchospasm (~2-fold the basal lung resistance), previous inhibition of ectonucleotidases by ARL-67156 greatly intensified this response (~11-fold the basal lung resistance, with 44% mortality). Bronchoalveolar lavage fluid obtained during this bronchospasm contained increased ATP concentration. This potentiation was abolished by antagonism of purinergic receptors (suramin+RB2) or TXA2 receptor (SQ29548), or by intratracheal apyrase. In tracheal rings and lung parenchyma strips, OVA caused a concentration-dependent contraction. Suramin+RB2 or levamisole produced a significant rightward displacement of this response, and ARL-67156 did not modify it. Platelets stimulated with OVA released ATP. Confocal images of nonsensitized tracheas showed slight fluorescence for P2Y6 receptors in epithelium and none for P2Y4 . Sensitized animals showed strong fluorescence to both receptors and to alkaline phosphatase in the airway epithelium. This correlated with a large increment in mRNA for P2Y4 and P2Y6 receptors in sensitized animals. CONCLUSIONS Nucleotides greatly potentiate the allergic bronchospasm when ectonucleotidases activity is diminished, and this effect is probably favored by the upregulation of P2Y4 and P2Y6 receptors in airway epithelium during sensitization. These results prompt for further research on these mechanisms in human asthma.
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Affiliation(s)
- J. Chávez
- Departamento de Investigación en Hiperreactividad Bronquial; Instituto Nacional de Enfermedades Respiratorias; México; DF; México
| | - M. H. Vargas
- Departamento de Investigación en Hiperreactividad Bronquial; Instituto Nacional de Enfermedades Respiratorias; México; DF; México
| | - D. C. Rebollar-Ayala
- Departamento de Farmacología; Facultad de Medicina; Universidad Nacional Autónoma de México; México; DF; México
| | - V. Díaz-Hernández
- Departamento de Embriología; Facultad de Medicina; Universidad Nacional Autónoma de México; México; DF; México
| | - J. E. Cruz-Valderrama
- Departamento de Farmacología; Facultad de Medicina; Universidad Nacional Autónoma de México; México; DF; México
| | - E. Flores-Soto
- Departamento de Farmacología; Facultad de Medicina; Universidad Nacional Autónoma de México; México; DF; México
| | - M. Flores-García
- Departamento de Biología Molecular; Instituto Nacional de Cardiología; México; DF; México
| | - N. N. Jiménez-Vargas
- División de Biología Molecular; Instituto Potosino de Investigación Científica y Tecnológica; San Luis Potosí; S.L.P.; México
| | - C. Barajas-López
- División de Biología Molecular; Instituto Potosino de Investigación Científica y Tecnológica; San Luis Potosí; S.L.P.; México
| | - L. M. Montaño
- Departamento de Farmacología; Facultad de Medicina; Universidad Nacional Autónoma de México; México; DF; México
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Histamine, carbachol, and serotonin induce hyperresponsiveness to ATP in guinea pig tracheas: involvement of COX-2 pathway. Pflugers Arch 2013; 465:1171-9. [PMID: 23475395 DOI: 10.1007/s00424-013-1253-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 02/07/2013] [Accepted: 02/17/2013] [Indexed: 02/06/2023]
Abstract
Extracellular ATP promotes an indirect contraction of airway smooth muscle via the secondary release of thromboxane A2 (TXA2) from airway epithelium. Our aim was to evaluate if common contractile agonists modify this response to ATP. Tracheas from sensitized guinea pigs were used to evaluate ATP-induced contractions before and after a transient contraction produced by histamine, carbachol, or serotonin. Epithelial mRNA for COX-1 and COX-2 was measured by RT-PCR and their expression assessed by immunohistochemistry. Compared with the initial response, ATP-induced contraction was potentiated by pretreatment with histamine, carbachol, or serotonin. Either suramin (antagonist of P2X and P2Y receptors) plus RB2 (antagonist of P2Y receptors) or indomethacin (inhibitor of COX-1 and COX-2) annulled the ATP-induced contraction, suggesting that it was mediated by P2Y receptor stimulation and TXA2 production. When COX-2 was inhibited by SC-58125 or thromboxane receptors were antagonized by SQ-29548, just the potentiation was abolished, leaving the basal response intact. Airway epithelial cells showed increased COX-2 mRNA after stimulation with histamine or carbachol, but not serotonin, while COX-1 mRNA was unaffected. Immunochemistry corroborated this upregulation of COX-2. In conclusion, we showed for the first time that histamine and carbachol cause hyperresponsiveness to ATP by upregulating COX-2 in airway epithelium, which likely increases TXA2 production. Serotonin-mediated hyperresponsiveness seems to be independent of COX-2 upregulation, but nonetheless is TXA2 dependent. Because acetylcholine, histamine, and serotonin can be present during asthmatic exacerbations, their potential interactions with ATP might be relevant in its pathophysiology.
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Gallego D, Gil V, Martínez-Cutillas M, Mañé N, Martín MT, Jiménez M. Purinergic neuromuscular transmission is absent in the colon of P2Y(1) knocked out mice. J Physiol 2012; 590:1943-56. [PMID: 22371472 DOI: 10.1113/jphysiol.2011.224345] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Purinergic and nitrergic co-transmission is the dominant mechanism responsible for neural-mediated smooth muscle relaxation in the gastrointestinal tract. The aim of the present paper was to test whether or not P2Y(1) receptors are involved in purinergic neurotransmission using P2Y(1)(−/−) knock-out mice. Tension and microelectrode recordings were performed on colonic strips. In wild type (WT) animals, electrical field stimulation (EFS) caused an inhibitory junction potential (IJP) that consisted of a fast IJP (MRS2500 sensitive, 1 μm) followed by a sustained IJP (N(ω)-nitro-L-arginine (L-NNA) sensitive, 1 mm). The fast component of the IJP was absent in P2Y(1)(−/−) mice whereas the sustained IJP (L-NNA sensitive) was recorded. In WT animals, EFS-induced inhibition of spontaneous motility was blocked by the consecutive addition of L-NNA and MRS2500. In P2Y(1)(−/−) mice, EFS responses were completely blocked by L-NNA. In WT and P2Y(1)(−/−) animals, L-NNA induced a smooth muscle depolarization but ‘spontaneous' IJP (MRS2500 sensitive) could be recorded in WT but not in P2Y(1)(−/−) animals. Finally, in WT animals, 1 μm MRS2365 caused a smooth muscle hyperpolarization that was blocked by 1 μm MRS2500. In contrast, 1 μm MRS2365 did not modify smooth muscle resting membrane potential in P2Y(1)(−/−) mice. β-Nicotinamide adenine dinucleotide (β-NAD, 1 mm) partially mimicked the effect of MRS2365. We conclude that P2Y(1) receptors mediate purinergic neurotransmission in the gastrointestinal tract and β-NAD partially fulfils the criteria to participate in rodent purinergic neurotransmission. The P2Y(1)(−/−) mouse is a useful animal model to study the selective loss of purinergic neurotransmission.
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Affiliation(s)
- Diana Gallego
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) Instituto de Salud Carlos III, Barcelona, Spain
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Pharmacological characterization of uracil nucleotide-preferring P2Y receptors modulating intestinal motility: a study on mouse ileum. Purinergic Signal 2011; 8:275-85. [PMID: 22102167 DOI: 10.1007/s11302-011-9281-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Accepted: 11/07/2011] [Indexed: 01/08/2023] Open
Abstract
We investigated the possible modulation of the intestinal contractility by uracil nucleotides (UTP and UDP), using as model the murine small intestine. Contractile activity of a mouse ileum longitudinal muscle was examined in vitro as changes in isometric tension. Transcripts encoding for uracil-sensitive receptors was investigated by RT-PCR. UDP induced muscular contractions, sensitive to PPADS, suramin, or MRS 2578, P2Y(6) receptor antagonist, and mimicked by PSB 0474, P2Y(6)-receptor agonist. UTP induced biphasic effects characterized by an early inhibition of the spontaneous contractile activity followed by muscular contraction. UTP excitatory effects were antagonized by PPADS, suramin, but not by MRS 2578, whilst the inhibitory effects were antagonized by PPADS but not by suramin or MRS 2578. UTPγS, P2Y(2)/(4) receptor agonist but not 2-thio-UTP, P2Y(2) receptor agonist, mimicked UTP effects. The inhibitory effects induced by UTP was abolished by ATP desensitization and increased by extracellular acidification. UDP or UTP responses were insensitive to TTX, atropine, or L-NAME antagonized by U-73122, inhibitor of phospholipase C (PLC) and preserved in the presence of nifedipine or low Ca(2+) solution. Transcripts encoding the uracil nucleotide-preferring receptors were expressed in mouse ileum. Functional postjunctional uracil-sensitive receptors are present in the longitudinal muscle of the mouse ileum. Activation of P2Y(6) receptors induces muscular contraction, whilst activation of P2Y(4) receptors leads to inhibition of the contractile activity. Indeed, the presence of atypical UTP-sensitive receptors leading to muscular contraction is suggested. All uracil-sensitive receptors are linked to the PLC pathway.
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Using antibodies against P2Y and P2X receptors in purinergic signaling research. Purinergic Signal 2011; 8:61-79. [PMID: 22086554 PMCID: PMC3265709 DOI: 10.1007/s11302-011-9278-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Accepted: 10/13/2011] [Indexed: 01/07/2023] Open
Abstract
The broad expression pattern of the G protein-coupled P2Y receptors has demonstrated that these receptors are fundamental determinants in many physiological responses, including neuromodulation, vasodilation, inflammation, and cell migration. P2Y receptors couple either G(q) or G(i) upon activation, thereby activating different signaling pathways. Ionotropic ATP (P2X) receptors bind extracellular nucleotides, a signal which is transduced within the P2X protein complex into a cation channel opening, which usually leads to intracellular calcium concentration elevation. As such, this family of proteins initiates or shapes several cellular processes including synaptic transmission, gene expression, proliferation, migration, and apoptosis. The ever-growing range of applications for antibodies in the last 30 years attests to their major role in medicine and biological research. Antibodies have been used as therapeutic tools in cancer and inflammatory diseases, as diagnostic reagents (flow cytometry, ELISA, and immunohistochemistry, to name a few applications), and in widespread use in biological research, including Western blot, immunoprecipitation, and ELISPOT. In this article, we will showcase several of the advances that scientists around the world have achieved using the line of antibodies developed at Alomone Labs for P2Y and P2X receptors.
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Priem EKV, Lefebvre RA. Investigation of neurogenic excitatory and inhibitory motor responses and their control by 5-HT(4) receptors in circular smooth muscle of pig descending colon. Eur J Pharmacol 2011; 667:365-74. [PMID: 21723862 DOI: 10.1016/j.ejphar.2011.06.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Revised: 06/01/2011] [Accepted: 06/14/2011] [Indexed: 01/30/2023]
Abstract
The aim of this study was to investigate whether the pig colon descendens might be a good model for the responses mediated via the different locations of human colonic 5-HT(4) receptors. The intrinsic excitatory and inhibitory motor neurotransmission in pig colon descendens was therefore first characterized. In circular smooth muscle strips, electrical field stimulation (EFS) at basal tone induced only in the combined presence of the NO synthase inhibitor N(ω)-nitro-L-arginine methyl ester hydrochloride (L-NAME) and the SK channel blocker apamin voltage-dependent on-contractions. These on-contractions were largely reduced by the neuronal conductance blocker tetrodotoxin (TTX) and by the muscarinic receptor antagonist atropine, illustrating activation of cholinergic neurons. The 5-HT(4) receptor agonist prucalopride facilitated submaximal EFS-evoked cholinergic contractions and this effect was prevented by the 5-HT(4) receptor antagonist GR113808, supporting the presence of facilitating 5-HT(4) receptors on the cholinergic nerve endings innervating circular muscle in pig colon descendens. Relaxations were induced by EFS in strips pre-contracted with substance P in the presence of atropine. The responses at lower stimulation voltages were abolished by TTX. L-NAME or apamin alone did not influence or only moderately reduced the relaxations, but L-NAME plus apamin abolished the relaxations at lower stimulation voltages, suggesting that NO and ATP act as inhibitory neurotransmitters in a redundant way. Prucalopride did not influence the EFS-induced relaxations at lower stimulation voltage, nor did it per se relax contracted circular muscle strips. No evidence for relaxing 5-HT(4) receptors, either on inhibitory neurons or on the muscle cells was thus obtained in pig colon descendens circular muscle.
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Characterization of P2Y receptors mediating ATP induced relaxation in guinea pig airway smooth muscle: involvement of prostaglandins and K+ channels. Pflugers Arch 2011; 462:573-85. [PMID: 21800025 DOI: 10.1007/s00424-011-0997-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Revised: 06/14/2011] [Accepted: 07/15/2011] [Indexed: 01/13/2023]
Abstract
In airway smooth muscle (ASM), adenosine 5'-triphosphate (ATP) induces a relaxation associated with prostaglandin production. We explored the role of K(+) currents (I (K)) in this relaxation. ATP relaxed the ASM, and this effect was abolished by indomethacin. Removal of airway epithelium slightly diminished the ATP-induced relaxation at lower concentration without modifying the responses to ATP at higher concentrations. ATPγS and UTP induced a concentration-dependent relaxation similar to ATP; α,β-methylene-ATP was inactive from 1 to 100 μM. Suramin or reactive blue 2 (RB2), P2Y receptor antagonists, did not modify the relaxation, but their combination significantly reduced this effect of ATP. The relaxation was also inhibited by N-ethylmaleimide (NEM; which uncouples G proteins). In myocytes, the ATP-induced I (K) increment was not modified by suramin or RB2 but the combination of both drugs abolished it. This increment in the I (K) was also completely nullified by NEM and SQ 22,536. 4-Amynopyridine or iberiotoxin diminished the ATP-induced I (K) increment, and the combination of both substances diminished ATP-induced relaxation. The presence of P2Y(2) and P2Y(4) receptors in smooth muscle was corroborated by Western blot and confocal images. In conclusion, ATP: (1) produces relaxation by inducing the production of bronchodilator prostaglandins in airway smooth muscle, most likely by acting on P2Y(4) and P2Y(2) receptors; (2) induces I (K) increment through activation of the delayed rectifier K(+) channels and the high-conductance Ca(2+)-dependent K(+) channels, therefore both channels are implicated in the ATP-induced relaxation; and (3) this I (K) increment is mediated by prostaglandin production which in turns increase cAMP signaling pathway.
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Choi KH, Jeong SI, Lee JH, Hwang BS, Lee S, Choi BK, Jung KY. Acetylene compound isolated from Atractylodes japonica stimulates the contractility of rat distal colon via inhibiting the nitrergic-purinergic relaxation. JOURNAL OF ETHNOPHARMACOLOGY 2011; 134:104-110. [PMID: 21130855 DOI: 10.1016/j.jep.2010.11.059] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Revised: 11/13/2010] [Accepted: 11/25/2010] [Indexed: 05/30/2023]
Abstract
AIM OF THE STUDY Our previous research has showed that rhizome of Atractylodes japonica Koidz (Compositae) exhibits an increase in the spontaneous contractility of distal colon in rats. The aims of this study are to identify the phytochemical(s), which stimulate(s) the colonic contractility, contained in Atractylodes japonica and to evaluate the pharmacological mechanism responsible for the colonic muscle contraction. MATERIALS AND METHODS Based on the stimulatory activity-guided fractionation on the isometric contraction of rat distal colonic strips, atractylodiol (ATD) and diacetyl-atractylodiol (DATD) were isolated from the CHCl(3) fractions of Atractylodes japonica. RESULTS ATD and DATD dose-dependently increased both tension and amplitude of distal colon longitudinal muscle (DCLM), but they stimulated only amplitude in the distal colon circular muscle. The ED(50) values of ATD and DATD to stimulate the amplitude of DCLM were revealed as 9.1×10(-9)M and 1.8×10(-8)M, respectively. l-NAME (0.1mM) significantly increased the ADT (1μM)-induced contraction of DCLM, whereas SNAP (0.1mM) markedly reduced the stimulatory effects of ATD on DCLM contractility. The combined effects of SNAP and atropine (0.5μM) on the ATD-induced contraction of DCLM were similar to the inhibitory effects of SNAP alone. Suramin (0.1mM) significantly enhanced the increase of ATD-induced DCLM contraction, whereas ADPβS (0.1mM) markedly abolished the stimulatory effects of ATD on the spontaneous contractility of DCLM. CONCLUSIONS The present results demonstrate that acetylene compounds, ATD and DATD, are the effective phytochemical of Atractylodes japonica to stimulate the motility of distal colon in rats, and ATD possibly enhances the spontaneous contractility of distal colon through inhibiting the mechanism of nitrergic-purinergic relaxation.
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Affiliation(s)
- Keun Han Choi
- Department of Pharmacology, College of Medicine, Wonkwang University, 344-2 Shinyong-dong, Iksan, Jeonbuk 570-749, Republic of Korea
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ATP induces contraction mediated by the P2Y(2) receptor in rat intestinal subepithelial myofibroblasts. Eur J Pharmacol 2011; 657:152-8. [PMID: 21296070 DOI: 10.1016/j.ejphar.2011.01.047] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Revised: 01/21/2011] [Accepted: 01/25/2011] [Indexed: 01/29/2023]
Abstract
Intestinal subepithelial myofibroblasts (IMFs) exist just under the epithelial membrane directly facing the mucosal microvascular capillary surface distributed in the lamina propria. In the gastrointestinal tract, ATP is released from epithelial and endothelial cells in response to mechanical stimuli. Although it has been reported that mechanical stimuli evoke synchronized Ca(2+) waves in cultured IMFs, the contractile responses by ATP stimulation have not been examined. The aim of this study was to clarify the mechanism of the contraction of IMFs in response to ATP. ATP (1-30μM) induced contraction in a concentration-dependent manner. These contractions were inhibited by LaCl(3) (100-300μM) and by Ca(2+)-free solution (0.5mM EGTA). Fura-2/Ca(2+) signals indicated that ATP (1-10μM) elicited transient increases in intracellular Ca(2+) concentration ([Ca(2+)](i)). In addition, αβ-methylene-ATP (10, 30 and 300μM), a broad spectrum P2X agonist at a concentration higher than 100μM, induced neither contraction nor [Ca(2+)](i) rise. UTP (1-30μM), a selective P2Y(2) and P2Y(4) agonist in rodent, induced concentration-dependent contractions and [Ca(2+)](i) increases, whereas ADP and UDP (10μM) did not induce contractions. Pretreatment with suramin (30-100μM), a relatively selective P2Y(2) antagonist, strongly inhibited ATP- and UTP-induced contractions and [Ca(2+)](i) increases. However, pyridoxal-phosphate-6-azophenyl-2',4'-disulfonate (PPADS: 10-30μM), a receptor antagonist for several P2X and P2Y but less effective to P2Y(2) receptor, failed to inhibit ATP- and UTP-induced contractions and [Ca(2+)](i) increases. By RT-PCR, mRNA expressions of the P2Y(1) and P2Y(2) receptors, but not P2Y(4) or P2Y(6), were detected in IMFs. These results suggest that ATP induces [Ca(2+)](i)-dependent contraction in IMFs, which is mediated through the P2Y(2) receptor.
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van Nassauw L, Timmermans JP. Detailed knowledge of cellular expression of G protein-coupled receptors in the human enteric nervous system is essential for understanding their diverse actions. Neurogastroenterol Motil 2010; 22:959-64. [PMID: 20701687 DOI: 10.1111/j.1365-2982.2010.01575.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
G protein-coupled receptors (GPCRs) comprise a large and diverse superfamily of transmembrane receptors that mediate the functions of an extraordinarily large number of extracellular ligands. They control many major physiological processes and are involved in diverse pathological processes, including gastrointestinal diseases. G protein-coupled receptors are one of the most targeted classes in pharmaceutical drug research. At present, much of our knowledge concerning the expression, distribution and function of GPCRs in the gut has been gleaned from studies performed in experimental models. Data obtained in the human digestive tract, especially in the enteric nervous system, are sparse and incomplete, although enteric neurons have a key position in almost all physiological and pathophysiological processes in the gut. Knowledge of cellular distribution of GPCRs, of regional differences in GPCR expression, and of altered GPCR expression during pathophysiological conditions in the human gut, will lead to a better understanding of GPCR activity, but will also contribute to the development of new drugs. In the current issue of the Journal, Harrington et al. describe the presence and cellular localization of muscarinic receptors in the human colon. Morphologically, orientated studies on the cellular expression of GPCRs in the human gut have to be encouraged, because these studies will yield data that are of therapeutic relevance.
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Affiliation(s)
- L van Nassauw
- Laboratory of Cell Biology & Histology, Department of Veterinary Sciences, University of Antwerp, Antwerpen, Belgium
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Aronsson P, Andersson M, Ericsson T, Giglio D. Assessment and characterization of purinergic contractions and relaxations in the rat urinary bladder. Basic Clin Pharmacol Toxicol 2010; 107:603-13. [PMID: 20406212 DOI: 10.1111/j.1742-7843.2010.00554.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The aim of the present study was to assess the purinoceptor functional responses of the urinary bladder by using isolated rat urinary bladder strip preparations. ATP elicited a transient bladder contraction followed by a sustained relaxation and ADP, UDP and UTP generated predominantly potent relaxations (relaxatory potencies: ADP = ATP > UDP = UTP). The ATP contractions were desensitized with the P2X(1/3) purinoceptor agonist/desensitizer alpha,beta-meATP and reduced by the P2 purinoceptor antagonist PPADS but unaffected by the P2 purinoceptor antagonist suramin. Electrical field stimulation (1-60 Hz) evoked frequency-dependent bladder contractions that were decreased by incubation with alpha,beta-meATP but not further decreased by PPADS. Suramin antagonized relaxations generated by UDP but not those by ADP, ATP or UTP. PPADS antagonized and tended to antagonize UTP and UDP relaxations, respectively, but did neither affect ADP nor ATP relaxations. ADP relaxations were insensitive to the P2Y(1) purinoceptor antagonist MRS 2179 and the ATP-sensitive potassium channel antagonist glibenclamide. The ATP relaxations were inhibited by the P1 purinoceptor antagonist 8-p-sulfophenyltheophylline but unaffected by the A2A adenosine receptor antagonist 8-(3-chlorostyryl)caffeine and glibenclamide. Adenosine evoked relaxations that were antagonized by the A2B adenosine receptor antagonist PSB 1115. Thus, in the rat urinary bladder purinergic contractions are elicited predominantly by stimulation of the P2X(1) purinoceptors, while UDP/UTP-sensitive P2Y purinoceptor(s) and P1 purinoceptors of the A2B adenosine receptor subtype are involved in bladder relaxation.
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Affiliation(s)
- Patrik Aronsson
- Department of Pharmacology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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Grasa L, Gil V, Gallego D, Martín MT, Jiménez M. P2Y(1) receptors mediate inhibitory neuromuscular transmission in the rat colon. Br J Pharmacol 2010; 158:1641-52. [PMID: 19906120 DOI: 10.1111/j.1476-5381.2009.00454.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND AND PURPOSE Inhibitory junction potentials (IJP) are responsible for smooth muscle relaxation in the gastrointestinal tract. The aim of this study was to pharmacologically characterize the neurotransmitters [nitric oxide (NO) and adenosine triphosphate (ATP)] and receptors involved at the inhibitory neuromuscular junctions in the rat colon using newly available P2Y(1) antagonists. EXPERIMENTAL APPROACH Organ bath and microelectrode recordings were used to evaluate the effect of drugs on spontaneous mechanical activity and resting membrane potential. IJP and mechanical relaxation were studied using electrical field stimulation (EFS). KEY RESULTS N(omega)-nitro-L-arginine (L-NNA) inhibited the slow component of the IJP and partially inhibited the mechanical relaxation induced by EFS. MRS2179, MRS2500 and MRS2279, all selective P2Y(1) receptor antagonists, inhibited the fast component of the IJP without having a major effect on the relaxation induced by EFS. The combination of both L-NNA and P2Y(1) antagonists inhibited the fast and the slow components of the IJP and completely blocked the mechanical relaxation induced by EFS. Sodium nitroprusside caused smooth muscle hyperpolarization and cessation of spontaneous motility that was prevented by oxadiazolo[4,3-alpha]quinoxalin-1-one. Adenosine 5'-O-2-thiodiphosphate, a preferential P2Y agonist, hyperpolarized smooth muscle cells and decreased spontaneous motility. This effect was inhibited by P2Y(1) antagonists. CONCLUSIONS AND IMPLICATIONS The co-transmission process in the rat colon involves ATP and NO. P2Y(1) receptors mediate the fast IJP and NO the slow IJP. The rank order of potency of the P2Y(1) receptor antagonists is MRS2500 greater than MRS2279 greater than MRS2179. P2Y(1) receptors might be potential pharmacological targets for the regulation of gastrointestinal motility.
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Affiliation(s)
- Laura Grasa
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain
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Zhang Y, Lomax AE, Paterson WG. P2Y1 receptors mediate apamin-sensitive and -insensitive inhibitory junction potentials in murine colonic circular smooth muscle. J Pharmacol Exp Ther 2010; 333:602-11. [PMID: 20103587 DOI: 10.1124/jpet.109.160978] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Purinergic inhibitory neuromuscular transmission plays an important role in the control of intestinal motility. In most tissues this neurotransmission is apamin-sensitive, but recent studies in human colonic circular smooth muscle (CSM) suggest the presence of apamin-insensitive purinergic inhibitory junction potentials (IJPs). The current studies used conventional intracellular recordings on colonic CSM strips to characterize the purinergic IJPs in murine colonic CSM. P2Y1 receptor expression was examined by using reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry. The IJP induced by nerve stimulation (NS) of one and four pulses in neuronal nitric-oxide synthase knockout mice consists of an apamin-sensitive and a dominant apamin-resistant component. These are identical to the IJPs in wild-type and CD1 mice in the presence of N(omega)-nitro-l-arginine methyl ester (200 microM) and were significantly inhibited by alpha,beta-methylene ATP (50 microM), an analog of ATP. IJPs were not affected by the P2X receptor antagonist 2',3'-o-(2,4,6-trinitrophenyl)-ATP (10 microM). Furthermore, apamin-resistant IJPs induced by single-pulse NS were abolished by pyridoxal-phosphate-6-azophenyl-2',4'-disulfonate (100 microM), a P2 receptor antagonist; 2'-deoxy-N6-methyl adenosine 3,5-diphosphate (MRS-2179; 10 microM), a selective P2Y1 receptor antagonist; and tetrodotoxin (1 microM). Aboral NS induced apamin-sensitive purinergic IJPs, whereas oral and circumferential NS produced apamin-sensitive and -resistant IJPs, with the latter predominating. RT-PCR and immunohistochemistry confirmed the presence of P2Y1 receptors on smooth muscle and in the myenteric plexus. These data suggest that, depending on stimulus location, activation of P2Y1 receptors produces both apamin-sensitive and apamin-resistant IJPs in murine colonic CSM.
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Affiliation(s)
- Yong Zhang
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
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Expression of P2X6 receptors in the enteric nervous system of the rat gastrointestinal tract. Histochem Cell Biol 2009; 133:177-88. [PMID: 19946698 DOI: 10.1007/s00418-009-0659-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/23/2009] [Indexed: 12/13/2022]
Abstract
Expression of P2X(4) and P2X(6) receptor subunits in the gastrointestinal tract of the rat was studied with double-labeling fluorescence immunohistochemistry. The results showed that P2X(6) receptors were expressed widely in the submucosal and myenteric plexuses. In the myenteric plexus, P2X(6) receptors were expressed mainly in large size neurons which resembled Dogiel type II neurons. These P2X(6) receptor-immunoreactive (ir) neurons also expressed calbindin 28K, calretinin and neuronal nuclei (NeuN), proteins that are markers of intrinsic sensory neurons. In the submucosal plexus, all the calbindin 28K, calretinin and NeuN-ir cells were immunoreactive for P2X(6) receptors. P2X(6) receptors do not form homomultimers, but rather heteromultimers with either P2X(2) or P2X(4) receptors. P2X(4) receptors were not expressed in neurons, but were expressed in macrophages of the rat gastrointestinal tract. These data indicate that P2X(6) receptors are mainly expressed on intrinsic sensory neurons and that ATP, via P2X(6) receptors probably in heteromeric combination with P2X(2) receptors, may be involved in regulating the physiological functions of these neurons.
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Chandrasekharan BP, Kolachala VL, Dalmasso G, Merlin D, Ravid K, Sitaraman SV, Srinivasan S. Adenosine 2B receptors (A(2B)AR) on enteric neurons regulate murine distal colonic motility. FASEB J 2009; 23:2727-34. [PMID: 19357134 DOI: 10.1096/fj.09-129544] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Delayed colonic emptying leading to constipation is a significant health concern. We investigated the role of adenosine 2B receptor (A(2B)AR) in modulating distal colonic motility using wild-type and A(2B)AR-knockout (A(2B)AR(-/-)) mice. Colon motility was assessed using stool characteristics and colonic transit. Distal colonic ganglia, isolated by laser capture microdissection, were tested for A(2B)AR expression by RT-PCR. The distal colon contraction and relaxation responses were assessed by electrical field stimulation (EFS) in presence of A(2B)AR agonists, antagonists or inhibitors of nitric oxide (NO) and guanylate cyclase. Nitrite levels were measured in enteric neuronal cultures exposed to A(2B)AR agonists/antagonists. A(2B)AR(-/-) mice display increased stool retention, decreased stool frequency, delayed colonic emptying, and decreased circular muscle relaxation. RT-PCR identified A(2B)AR expression in distal colonic ganglia. EFS studies revealed that enteric neuronal A(2B)AR is essential for distal colonic relaxation, and A(2B)AR antagonists can inhibit relaxation. Enteric neurons stimulated with A(2B)AR agonists produced more nitrite than cultures treated with antagonists. We demonstrate an essential role of A(2B)AR in regulating distal colon relaxation, as A(2B)AR activation is linked to NO signaling. Hence targeting the colonic A(2B)AR could represent a novel therapeutic strategy to treat constipation.
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Hejazian-Y SH, Dashti-R MH, Mahdavi SM, Qureshi MA. The effect of Carum Copticum extract on acetylcholine induced contraction in isolated rat's ileum. J Acupunct Meridian Stud 2009; 2:75-8. [PMID: 20633478 DOI: 10.1016/s2005-2901(09)60019-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2008] [Accepted: 01/13/2009] [Indexed: 10/20/2022] Open
Abstract
AIMS There are many biological investigations for determining an effective cure for the dysfunction of gastrointestinal tracts, using herbal medicine. It has been reported that Carum Copticum is a bactericidal agent and possesses anticholinergic, antihistaminic and b-adrenergic stimulatory effects in some tissues. However, these effects of Carum Copticum on mechanical activities of isolated intestine are not clearly identified yet. The present study has been designed to find out the specific effects of Carum Copticum on mechanical activity of isolated rat's ileum. MATERIALS AND METHODS In this study rat's ileum contraction was recorded through an isolated tissue chamber in an organ bath by using isotonic transducer and oscillographic device. The effect of Carum Copticum extract on acetylcholine induced contraction in isolated rat's ileum was evaluated. RESULTS Our findings showed that 1% aqueous extract of Carum Copticum reduces the basal contractile activity of rat's ileum. The extract also reduced acetylcholine induced contraction to 40% of its maximum response. The inhibitory action of Carum Copticum extract on acetylcholine induced contraction was similar but slower than that of atropine sulfate. CONCLUSION The results of this study showed an inhibitory effect of Carum Copticum extract on acetylcholine induced contraction in rat's ileum.
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Affiliation(s)
- Seyed Hassan Hejazian-Y
- Herbal Medicine Research Center, School of Medicine, Shahid Sadughi University of Medical Sciences and Health Services, Yazd, Iran
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Abstract
Purines appear to be the most primitive and widespread chemical messengers in the animal and plant kingdoms. The evidence for purinergic signalling in plants, invertebrates and lower vertebrates is reviewed. Much is based on pharmacological studies, but important recent studies have utilized the techniques of molecular biology and receptors have been cloned and characterized in primitive invertebrates, including the social amoeba Dictyostelium and the platyhelminth Schistosoma, as well as the green algae Ostreococcus, which resemble P2X receptors identified in mammals. This suggests that contrary to earlier speculations, P2X ion channel receptors appeared early in evolution, while G protein-coupled P1 and P2Y receptors were introduced either at the same time or perhaps even later. The absence of gene coding for P2X receptors in some animal groups [e.g. in some insects, roundworms (Caenorhabditis elegans) and the plant Arabidopsis] in contrast to the potent pharmacological actions of nucleotides in the same species, suggests that novel receptors are still to be discovered.
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Affiliation(s)
- G Burnstock
- Autonomic Neuroscience Centre, Royal Free and University College Medical School, London, UK.
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Smedlund K, Vazquez G. Involvement of native TRPC3 proteins in ATP-dependent expression of VCAM-1 and monocyte adherence in coronary artery endothelial cells. Arterioscler Thromb Vasc Biol 2008; 28:2049-55. [PMID: 18787184 DOI: 10.1161/atvbaha.108.175356] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
UNLABELLED Background- Vascular cell adhesion molecule-1 (VCAM-1) is critical in monocyte recruitment to the endothelium, a key event in development of atherosclerotic lesions. Stimulation of human coronary artery endothelial cells (HCAECs) with ATP positively modulates VCAM-1 expression and function through a mechanism involving Ca(2+) signaling. We here examined the role of Ca(2+) influx and native TRPC3 channels in that mechanism. METHODS AND RESULTS Omission of extracellular Ca(2+) or pretreatment of cells with channel blockers markedly reduced ATP-induced VCAM-1 and monocyte adhesion. Using a siRNA strategy and real-time fluorescence, we found that native TRPC3 proteins contribute to constitutive and ATP-regulated Ca(2+) influx. ATP-dependent upregulation of VCAM-1 was accompanied by an increase in basal cation entry and TRPC3 expression. Notably, TRPC3 knock-down resulted in a dramatic reduction of ATP-induced VCAM-1 and monocyte adhesion. CONCLUSIONS These findings indicate that in HCAECs, native TRPC3 proteins form channels that contribute to constitutive and ATP-dependent Ca(2+) influx, and that TRPC3 expression and function are fundamental to support VCAM-1 expression and monocyte binding. This is the first evidence to date relating native TRPC3 proteins with regulated expression of cell adhesion molecules in coronary endothelium, and suggests a potential pathophysiological role of TRPC3 in coronary artery disease.
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Affiliation(s)
- Kathryn Smedlund
- Department of Physiology and Pharmacology, Center for Diabetes and Endocrine Research, University of Toledo College of Medicine, Health Science Campus, Ohio 43614, USA
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Ren J, Bertrand PP. Purinergic receptors and synaptic transmission in enteric neurons. Purinergic Signal 2008; 4:255-66. [PMID: 18368519 PMCID: PMC2486344 DOI: 10.1007/s11302-007-9088-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2007] [Accepted: 11/06/2007] [Indexed: 12/16/2022] Open
Abstract
Purines such as ATP and adenosine participate in synaptic transmission in the enteric nervous system as neurotransmitters or neuromodulators. Purinergic receptors are localized on the cell bodies or nerve terminals of different functional classes of enteric neurons and, with other receptors, form unique receptor complements. Activation of purinergic receptors can regulate neuronal activity by depolarization, by regulating intracellular calcium, or by modulating second messenger pathways. Purinergic signaling between enteric neurons plays an important role in regulating specific enteric reflexes and overall gastrointestinal function. In the present article, we review evidence for purine receptors in the enteric nervous system, including P1 (adenosine) receptors and P2 (ATP) receptors. We will explore the role they play in mediating fast and slow synaptic transmission and in presynaptic inhibition of transmission. Finally, we will examine the molecular properties of the native receptors, their signaling mechanisms, and their role in gastrointestinal pathology.
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Affiliation(s)
- Jianhua Ren
- Neuroscience Program, Michigan State University, East Lansing, MI 48824 USA
| | - Paul P. Bertrand
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV 89557 USA
- Department of Physiology, School of Medical Sciences, University of New South Wales, Sydney, NSW 2052 Australia
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McDonnell B, Hamilton R, Fong M, Ward SM, Keef KD. Functional evidence for purinergic inhibitory neuromuscular transmission in the mouse internal anal sphincter. Am J Physiol Gastrointest Liver Physiol 2008; 294:G1041-51. [PMID: 18308858 DOI: 10.1152/ajpgi.00356.2007] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The neurotransmitter(s) underlying nitric oxide synthase (NOS)-independent neural inhibition in the internal anal sphincter (IAS) is still uncertain. The present study investigated the role of purinergic transmission. Contractile and electrical responses to electrical field stimulation of nerves (0.1-5 Hz for 10-60 s) were recorded in strips of mouse IAS. A single stimulus generated a 28-mV fast inhibitory junction potential (IJP) and relaxation. The NOS inhibitor N(omega)-nitro-l-arginine (l-NNA) reduced the fast IJP duration by 20%. Repetitive stimulation at 2.5-5 Hz caused a more sustained IJP and sustained relaxation. l-NNA reduced relaxation at 1 Hz and the sustained IJP at 2.5-5 Hz. All other experiments were carried out in the presence of NOS blockade. IJPs and relaxation were significantly reduced by the P2 receptor antagonists 4-[[4-formyl-5-hydroxy-6-methyl-3-[(phosphonooxy)methyl]-2-pyridinyl]azo]-1,3-benzenedisulfonic acid (PPADS) (100 microM), by desensitization of P2Y receptors with adenosine 5'-[beta-thio]diphosphate (ADP-betaS) (10 microM), and by the selective P2Y1 receptor blocker 2'-deoxy-N(6)-methyl adenosine 3',5'-diphosphate (MRS2179) (10 microM). Relaxation and IJPs were also significantly reduced by the K(+) channel blocker apamin (1 microM). Removal of extracellular potassium (K(o)) increased IJP amplitude to 205% of control, whereas return of K(o) 30 min later hyperpolarized cells by 19 mV and reduced IJP amplitude to 50% of control. Exogenous ATP (3 mM) relaxed muscles in the presence of TTX (1 microM) and hyperpolarized cells by 15 mV. In conclusion, these data suggest that purinergic transmission significantly contributes to NOS-independent neural inhibition in the mouse IAS. P2Y1 receptors, as well as at least one other P2 receptor subtype, contribute to this pathway. Purinergic receptors activate apamin-sensitive K(+) channels as well as other apamin-insensitive conductances leading to hyperpolarization and relaxation.
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Affiliation(s)
- Bronagh McDonnell
- Dept. of Physiology and Cell Biology, Univ. of Nevada, Reno, Reno, NV 89557, USA
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