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Schledwitz A, Sundel MH, Alizadeh M, Hu S, Xie G, Raufman JP. Differential Actions of Muscarinic Receptor Subtypes in Gastric, Pancreatic, and Colon Cancer. Int J Mol Sci 2021; 22:ijms222313153. [PMID: 34884958 PMCID: PMC8658119 DOI: 10.3390/ijms222313153] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 12/01/2021] [Accepted: 12/02/2021] [Indexed: 12/17/2022] Open
Abstract
Cancers arising from gastrointestinal epithelial cells are common, aggressive, and difficult to treat. Progress in this area resulted from recognizing that the biological behavior of these cancers is highly dependent on bioactive molecules released by neurocrine, paracrine, and autocrine mechanisms within the tumor microenvironment. For many decades after its discovery as a neurotransmitter, acetylcholine was thought to be synthesized and released uniquely from neurons and considered the sole physiological ligand for muscarinic receptor subtypes, which were believed to have similar or redundant actions. In the intervening years, we learned this former dogma is not tenable. (1) Acetylcholine is not produced and released only by neurons. The cellular machinery required to synthesize and release acetylcholine is present in immune, cancer, and other cells, as well as in lower organisms (e.g., bacteria) that inhabit the gut. (2) Acetylcholine is not the sole physiological activator of muscarinic receptors. For example, selected bile acids can modulate muscarinic receptor function. (3) Muscarinic receptor subtypes anticipated to have overlapping functions based on similar G protein coupling and downstream signaling may have unexpectedly diverse actions. Here, we review the relevant research findings supporting these conclusions and discuss how the complexity of muscarinic receptor biology impacts health and disease, focusing on their role in the initiation and progression of gastric, pancreatic, and colon cancers.
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Affiliation(s)
- Alyssa Schledwitz
- Department of Medicine, Division of Gastroenterology & Hepatology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.S.); (M.A.); (S.H.); (G.X.)
| | - Margaret H. Sundel
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
| | - Madeline Alizadeh
- Department of Medicine, Division of Gastroenterology & Hepatology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.S.); (M.A.); (S.H.); (G.X.)
- The Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Shien Hu
- Department of Medicine, Division of Gastroenterology & Hepatology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.S.); (M.A.); (S.H.); (G.X.)
- VA Maryland Healthcare System, Baltimore, MD 21201, USA
| | - Guofeng Xie
- Department of Medicine, Division of Gastroenterology & Hepatology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.S.); (M.A.); (S.H.); (G.X.)
- VA Maryland Healthcare System, Baltimore, MD 21201, USA
- Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Jean-Pierre Raufman
- Department of Medicine, Division of Gastroenterology & Hepatology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.S.); (M.A.); (S.H.); (G.X.)
- VA Maryland Healthcare System, Baltimore, MD 21201, USA
- Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Correspondence: ; Tel.: +1-410-328-8728
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Dobson GP, Morris JL, Biros E, Davenport LM, Letson HL. Major surgery leads to a proinflammatory phenotype: Differential gene expression following a laparotomy. Ann Med Surg (Lond) 2021; 71:102970. [PMID: 34745602 PMCID: PMC8554464 DOI: 10.1016/j.amsu.2021.102970] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Accepted: 10/17/2021] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND The trauma of surgery is a neglected area of research. Our aim was to examine the differential expression of genes of stress, metabolism and inflammation in the major organs of a rat following a laparotomy. MATERIALS AND METHODS Anaesthetised Sprague-Dawley rats were randomised into baseline, 6-hr and 3-day groups (n = 6 each), catheterised and laparotomy performed. Animals were sacrificed at each timepoint and tissues collected for gene and protein analysis. Blood stress hormones, cytokines, endothelial injury markers and coagulation were measured. RESULTS Stress hormone corticosterone significantly increased and was accompanied by significant increases in inflammatory cytokines, endothelial markers, increased neutrophils (6-hr), higher lactate (3-days), and coagulopathy. In brain, there were significant increases in M1 muscarinic (31-fold) and α-1A-adrenergic (39-fold) receptor expression. Cortical expression of metabolic genes increased ∼3-fold, and IL-1β by 6-fold at 3-days. Cardiac β-1-adrenergic receptor expression increased up to 8.4-fold, and M2 and M1 muscarinic receptors by 2 to 4-fold (6-hr). At 3-days, cardiac mitochondrial gene expression (Tfam, Mtco3) and inflammation (IL-1α, IL-4, IL-6, MIP-1α, MCP-1) were significantly elevated. Haemodynamics remained stable. In liver, there was a dramatic suppression of adrenergic and muscarinic receptor expression (up to 90%) and increased inflammation. Gut also underwent autonomic suppression with 140-fold increase in IL-1β expression (3-days). CONCLUSIONS A single laparotomy led to a surgical-induced proinflammatory phenotype involving neuroendocrine stress, cortical excitability, immune activation, metabolic changes and coagulopathy. The pervasive nature of systemic and tissue inflammation was noteworthy. There is an urgent need for new therapies to prevent hyper-inflammation and restore homeostasis following major surgery.
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Affiliation(s)
- Geoffrey P. Dobson
- Heart and Trauma Research Laboratory, College of Medicine and Dentistry, James Cook University, Townsville, 4811, Australia
| | - Jodie L. Morris
- Heart and Trauma Research Laboratory, College of Medicine and Dentistry, James Cook University, Townsville, 4811, Australia
| | - Erik Biros
- Heart and Trauma Research Laboratory, College of Medicine and Dentistry, James Cook University, Townsville, 4811, Australia
| | - Lisa M. Davenport
- Heart and Trauma Research Laboratory, College of Medicine and Dentistry, James Cook University, Townsville, 4811, Australia
| | - Hayley L. Letson
- Heart and Trauma Research Laboratory, College of Medicine and Dentistry, James Cook University, Townsville, 4811, Australia
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Kim B, Kwon H, Kim J, Kwon M, Lee J, Kim S, Nam J. The traditional medicine bojungikki-tang increases intestinal motility. Pharmacogn Mag 2021. [DOI: 10.4103/pm.pm_507_20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Liu JYH, Du P, Rudd JA. Acetylcholine exerts inhibitory and excitatory actions on mouse ileal pacemaker activity: role of muscarinic versus nicotinic receptors. Am J Physiol Gastrointest Liver Physiol 2020; 319:G97-G107. [PMID: 32475128 DOI: 10.1152/ajpgi.00003.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The effect of acetylcholine (ACh) on pacemaking and spontaneous contractions in the gastrointestinal tract is not well characterized. The current study aims to profile the effect of several muscarinic and nicotinic receptor agonists and antagonists on pacemaker potentials in the ICR mouse ileum. Pacemaker potentials of whole thickness mouse ileal segments were recorded extracellularly using a 60-channel microelectrode array (MEA) platform. A spatiotemporal analysis integrated the frequency, amplitude, and velocity measurements of pacemaker currents. Comparative data were obtained by recording spontaneous smooth muscle tone in a conventional organ bath. On the MEA, ACh (0.3-300 μM) and bethanechol (0.3-300 μM) significantly reduced ileal pacemaker potentials. The inhibitory effect of ACh was mimicked by donepezil (300 μM) but not nicotine (0.3-7 mM). Atropine (300 μM), but not hexamethonium (300 μM), reversed the inhibitory actions of ACh and bethanechol and revealed excitatory properties manifested as increases in pacemaker frequency. A spatial analysis also revealed that atropine, but not hexamethonium, reversed the ACh-induced distortion of pacemaker propagation activity. Atropine (0.001-3 mM) and hexamethonium (0.3-7 mM) alone were inactive. In the organ bath, ACh (300 nM) and bethanechol (30 μM) induced ileal tonic contractions, while inhibiting basal spontaneous contractions at 300 μM. Atropine (1 μM), but not hexamethonium (1-300 μM), reversed both the tonic contractions and the inhibition of the spontaneous contractions of ACh and bethanechol and revealed an excitatory effect manifested as an increasing in the frequency of contractions. Muscarinic, but not nicotinic, receptors appear to mediate the inhibitory actions of ACh on mouse ileal pacemaker potentials.NEW & NOTEWORTHY The study discovered an acute action of acetylcholine on pacemaker potentials that is mediated by muscarinic receptors on the mouse ileum. Bethanechol, but not nicotine, mimicked the inhibitory actions of acetylcholine on pacemaker potentials. Atropine, but not hexamethonium, reversed the inhibitory actions of acetylcholine. When introduced after acetylcholine, atropine exhibited excitatory actions that increased the pacemaker frequency. Acetylcholine and bethanechol distorted the propagation activity and pattern, and this was also reversed by atropine. These actions of acetylcholine on pacemaker potentials may contribute to pathophysiology in bowel diseases.
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Affiliation(s)
- Julia Yuen Hang Liu
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong Special Administrative Region, People's Republic of China
| | - Peng Du
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - John Anthony Rudd
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong Special Administrative Region, People's Republic of China
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Drumm BT, Rembetski BE, Huynh K, Nizar A, Baker SA, Sanders KM. Excitatory cholinergic responses in mouse colon intramuscular interstitial cells of Cajal are due to enhanced Ca 2+ release via M 3 receptor activation. FASEB J 2020; 34:10073-10095. [PMID: 32539213 DOI: 10.1096/fj.202000672r] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 05/01/2020] [Accepted: 05/11/2020] [Indexed: 12/14/2022]
Abstract
Colonic intramuscular interstitial cells of Cajal (ICC-IM) are associated with cholinergic varicosities, suggesting a role in mediating excitatory neurotransmission. Ca2+ release in ICC-IM activates Ano1, a Ca2+ -activated Cl- conductance, causing tissue depolarization and increased smooth muscle excitability. We employed Ca2+ imaging of colonic ICC-IM in situ, using mice expressing GCaMP6f in ICC to evaluate ICC-IM responses to excitatory neurotransmission. Expression of muscarinic type 2, 3 (M2 , M3 ), and NK1 receptors were enriched in ICC-IM. NK1 receptor agonists had minimal effects on ICC-IM, whereas neostigmine and carbachol increased Ca2+ transients. These effects were reversed by DAU 5884 (M3 receptor antagonist) but not AF-DX 116 (M2 receptor antagonist). Electrical field stimulation (EFS) in the presence of L-NNA and MRS 2500 enhanced ICC-IM Ca2+ transients. Responses were blocked by atropine or DAU 5884, but not AF-DX 116. ICC-IM responses to EFS were ablated by inhibiting Ca2+ stores with cyclopiazonic acid and reduced by inhibiting Ca2+ influx via Orai channels. Contractions induced by EFS were reduced by an Ano1 channel antagonist, abolished by DAU 5884, and unaffected by AF-DX 116. Colonic ICC-IM receive excitatory inputs from cholinergic neurons via M3 receptor activation. Enhancing ICC-IM Ca2+ release and Ano1 activation contributes to excitatory responses of colonic muscles.
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Affiliation(s)
- Bernard T Drumm
- Department of Physiology and Cell Biology, Reno School of Medicine, University of Nevada, Reno, NV, USA.,Department of Life & Health Science, Dundalk Institute of Technology, Dundalk, Ireland
| | - Benjamin E Rembetski
- Department of Physiology and Cell Biology, Reno School of Medicine, University of Nevada, Reno, NV, USA
| | - Kaitlin Huynh
- Department of Physiology and Cell Biology, Reno School of Medicine, University of Nevada, Reno, NV, USA
| | - Aqeel Nizar
- Department of Physiology and Cell Biology, Reno School of Medicine, University of Nevada, Reno, NV, USA
| | - Salah A Baker
- Department of Physiology and Cell Biology, Reno School of Medicine, University of Nevada, Reno, NV, USA
| | - Kenton M Sanders
- Department of Physiology and Cell Biology, Reno School of Medicine, University of Nevada, Reno, NV, USA
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Wang B, Murakami Y, Ono M, Fujikawa S, Matsuyama H, Unno T, Naitou K, Tanahashi Y. Muscarinic suppression of ATP-sensitive K + channels mediated by the M 3/G q/11/phospholipase C pathway contributes to mouse ileal smooth muscle contractions. Am J Physiol Gastrointest Liver Physiol 2018; 315:G618-G630. [PMID: 30001145 DOI: 10.1152/ajpgi.00069.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
ATP-sensitive K+ (KATP) channels are expressed in gastrointestinal smooth muscles, and their activity is regulated by muscarinic receptor stimulation. However, the physiological significance and mechanisms of muscarinic regulation of KATP channels are not fully understood. We examined the effects of the KATP channel opener cromakalim and the KATP channel blocker glibenclamide on electrical activity of single mouse ileal myocytes and on mechanical activity in ileal segment preparations. To explore muscarinic regulation of KATP channel activity and its underlying mechanisms, the effect of carbachol (CCh) on cromakalim-induced KATP channel currents ( IKATP) was studied in myocytes of M2 or M3 muscarinic receptor-knockout (KO) and wild-type (WT) mice. Cromakalim (10 µM) induced membrane hyperpolarization in single myocytes and relaxation in segment preparations from WT mice, whereas glibenclamide (10 µM) caused membrane depolarization and contraction. CCh (100 µM) induced sustained suppression of IKATP in cells from both WT and M2KO mice. However, CCh had a minimal effect on IKATP in M3KO and M2/M3 double-KO cells. The Gq/11 inhibitor YM-254890 (10 μM) and PLC inhibitor U73122 (1 μM), but not the PKC inhibitor calphostin C (1 μM), markedly decreased CCh-induced suppression of IKATP in WT cells. These results indicated that KATP channels are constitutively active and contribute to the setting of resting membrane potential in mouse ileal smooth muscles. M3 receptors inhibit the activity of these channels via a Gq/11/PLC-dependent but PKC-independent pathways, thereby contributing to membrane depolarization and contraction of smooth muscles. NEW & NOTEWORTHY We systematically investigated the regulation of ATP-sensitive K+ channels by muscarinic receptors expressed on mouse ileal smooth muscles. We found that M3 receptors inhibit the activity of ATP-sensitive K+ channels via a Gq/11/PLC-dependent, but PKC-independent, pathway. This muscarinic suppression of ATP-sensitive K+ channels contributes to membrane depolarization and contraction of smooth muscles.
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Affiliation(s)
- Ban Wang
- Department of Animal Medical Sciences, Faculty of Life Sciences, Kyoto Sangyo University , Kyoto , Japan
| | - Yuri Murakami
- Department of Animal Medical Sciences, Faculty of Life Sciences, Kyoto Sangyo University , Kyoto , Japan
| | - Maiki Ono
- Department of Animal Medical Sciences, Faculty of Life Sciences, Kyoto Sangyo University , Kyoto , Japan
| | - Saki Fujikawa
- Department of Animal Medical Sciences, Faculty of Life Sciences, Kyoto Sangyo University , Kyoto , Japan
| | - Hayato Matsuyama
- Laboratory of Pharmacology, Department of Veterinary Medicine, Gifu University , Gifu , Japan
| | - Toshihiro Unno
- Laboratory of Pharmacology, Department of Veterinary Medicine, Gifu University , Gifu , Japan
| | - Kiyotada Naitou
- Department of Basic Veterinary Science, Joint Faculty of Veterinary Medicine, Kagoshima University , Kagoshima , Japan
| | - Yasuyuki Tanahashi
- Department of Animal Medical Sciences, Faculty of Life Sciences, Kyoto Sangyo University , Kyoto , Japan
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Gholamnezhad Z, Ghorani V, Saadat S, Shakeri F, Boskabady MH. The effects of medicinal plants on muscarinic receptors in various types of smooth muscle. Phytother Res 2018; 32:2340-2363. [DOI: 10.1002/ptr.6179] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 06/25/2018] [Accepted: 07/20/2018] [Indexed: 12/15/2022]
Affiliation(s)
- Zahra Gholamnezhad
- Neurogenic Inflammation Research Center; Mashhad University of Medical Sciences; Mashhad Iran
- Department of Physiology, School of Medicine; Mashhad University of Medical Sciences; Mashhad Iran
| | - Vahideh Ghorani
- Department of Physiology, School of Medicine; Mashhad University of Medical Sciences; Mashhad Iran
- Pharmaciutical Research Center; Mashhad University of Medical Sciences; Mashhad Iran
| | - Saeideh Saadat
- Neurogenic Inflammation Research Center; Mashhad University of Medical Sciences; Mashhad Iran
- Department of Physiology, School of Medicine; Mashhad University of Medical Sciences; Mashhad Iran
| | - Farzaneh Shakeri
- Natural Products and Medicinal Plants Research Center; North Khorasan University of Medical Sciences; Bojnurd Iran
| | - Mohammad Hossein Boskabady
- Neurogenic Inflammation Research Center; Mashhad University of Medical Sciences; Mashhad Iran
- Department of Physiology, School of Medicine; Mashhad University of Medical Sciences; Mashhad Iran
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Excitatory Neuronal Responses of Ca 2+ Transients in Interstitial Cells of Cajal in the Small Intestine. eNeuro 2018; 5:eN-NWR-0080-18. [PMID: 29632869 PMCID: PMC5889480 DOI: 10.1523/eneuro.0080-18.2018] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 03/12/2018] [Indexed: 12/26/2022] Open
Abstract
Interstitial cells of Cajal (ICC) regulate smooth muscle excitability and motility in the gastrointestinal (GI) tract. ICC in the deep muscular plexus (ICC-DMP) of the small intestine are aligned closely with varicosities of enteric motor neurons and thought to transduce neural responses. ICC-DMP generate Ca2+ transients that activate Ca2+ activated Cl- channels and generate electrophysiological responses. We tested the hypothesis that excitatory neurotransmitters regulate Ca2+ transients in ICC-DMP as a means of regulating intestinal muscles. High-resolution confocal microscopy was used to image Ca2+ transients in ICC-DMP within murine small intestinal muscles with cell-specific expression of GCaMP3. Intrinsic nerves were stimulated by electrical field stimulation (EFS). ICC-DMP exhibited ongoing Ca2+ transients before stimuli were applied. EFS caused initial suppression of Ca2+ transients, followed by escape during sustained stimulation, and large increases in Ca2+ transients after cessation of stimulation. Basal Ca2+ activity and the excitatory phases of Ca2+ responses to EFS were inhibited by atropine and neurokinin 1 receptor (NK1) antagonists, but not by NK2 receptor antagonists. Exogenous ACh and substance P (SP) increased Ca2+ transients, atropine and NK1 antagonists decreased Ca2+ transients. Neurokinins appear to be released spontaneously (tonic excitation) in small intestinal muscles and are the dominant excitatory neurotransmitters. Subcellular regulation of Ca2+ release events in ICC-DMP may be a means by which excitatory neurotransmission organizes intestinal motility patterns.
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Korsten MA, Lyons BL, Radulovic M, Cummings TM, Sikka G, Singh K, Hobson JC, Sabiev A, Spungen AM, Bauman WA. Delivery of neostigmine and glycopyrrolate by iontophoresis: a nonrandomized study in individuals with spinal cord injury. Spinal Cord 2018; 56:212-217. [PMID: 29116244 PMCID: PMC5839930 DOI: 10.1038/s41393-017-0018-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 09/18/2017] [Accepted: 09/22/2017] [Indexed: 01/11/2023]
Abstract
STUDY DESIGN Phase I Clinical Trial. OBJECTIVES In this proof-of-principle study, the effectiveness and safety of transdermal administration of neostigmine/glycopyrrolate to elicit a bowel movement was compared to intravenous administration in patients with spinal cord injury. SETTING James J. Peters Veterans Affairs Medical Center (Bronx, NY). METHODS Individuals were screened for responsiveness (Physical Response) to intravenous neostigmine (0.03 mg/kg)/glycopyrrolate (0.006 mg/kg). Intravenous neostigmine/glycopyrrolate responders (Therapeutic Response) were administered low-dose transdermal neostigmine/glycopyrrolate [(0.05 mg/kg)/(0.01 mg/kg)] by iontophoresis. Non-responders to low-dose transdermal neostigmine/glycopyrrolate were administered high-dose transdermal neostigmine/glycopyrrolate [(0.07 mg/kg)/(0.014 mg/kg)] by iontophoresis. Bowel movement, bowel evacuation time, and cholinergic side effects were recorded. Visits were separated by 2 to 14 days. RESULTS Eighteen of 25 individuals (72.0%) had a bowel movement (20 ± 22 min) after intravenous neostigmine/glycopyrrolate. Of these 18 individuals, 5 individuals experienced a bowel movement with low-dose transdermal neostigmine/glycopyrrolate. Another five individuals had a bowel movement after high-dose transdermal neostigmine/glycopyrrolate administration. Fewer side effects were observed in individuals who received neostigmine/glycopyrrolate transdermally compared to those who were administered intravenous neostigmine/glycopyrrolate. CONCLUSIONS Transdermal administration of neostigmine/glycopyrrolate by iontophoresis appears to be a practical, safe, and effective approach to induce bowel evacuation in individuals with spinal cord injury.
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Affiliation(s)
- Mark A Korsten
- National Center for the Medical Consequences of Spinal Cord Injury, Bronx, NY, USA.
- Medical Service, James J. Peters VA Medical Center, Bronx, NY, USA.
- Department of Medicine, The Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Brian L Lyons
- National Center for the Medical Consequences of Spinal Cord Injury, Bronx, NY, USA
| | - Miroslav Radulovic
- National Center for the Medical Consequences of Spinal Cord Injury, Bronx, NY, USA
- Medical Service, James J. Peters VA Medical Center, Bronx, NY, USA
| | - Tradd M Cummings
- National Center for the Medical Consequences of Spinal Cord Injury, Bronx, NY, USA
| | - Gautam Sikka
- Medical Service, James J. Peters VA Medical Center, Bronx, NY, USA
- Department of Medicine, The Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Kamaldeep Singh
- National Center for the Medical Consequences of Spinal Cord Injury, Bronx, NY, USA
- Medical Service, James J. Peters VA Medical Center, Bronx, NY, USA
| | - Joshua C Hobson
- National Center for the Medical Consequences of Spinal Cord Injury, Bronx, NY, USA
| | - Anton Sabiev
- National Center for the Medical Consequences of Spinal Cord Injury, Bronx, NY, USA
| | - Ann M Spungen
- National Center for the Medical Consequences of Spinal Cord Injury, Bronx, NY, USA
- Department of Medicine, The Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Rehabilitation Medicine, The Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - William A Bauman
- National Center for the Medical Consequences of Spinal Cord Injury, Bronx, NY, USA
- Medical Service, James J. Peters VA Medical Center, Bronx, NY, USA
- Department of Medicine, The Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Rehabilitation Medicine, The Icahn School of Medicine at Mount Sinai, New York, NY, USA
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Blair PJ, Rhee PL, Sanders KM, Ward SM. The significance of interstitial cells in neurogastroenterology. J Neurogastroenterol Motil 2014; 20:294-317. [PMID: 24948131 PMCID: PMC4102150 DOI: 10.5056/jnm14060] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 06/06/2014] [Accepted: 06/07/2014] [Indexed: 12/21/2022] Open
Abstract
Smooth muscle layers of the gastrointestinal tract consist of a heterogeneous population of cells that include enteric neurons, several classes of interstitial cells of mesenchymal origin, a variety of immune cells and smooth muscle cells (SMCs). Over the last number of years the complexity of the interactions between these cell types has begun to emerge. For example, interstitial cells, consisting of both interstitial cells of Cajal (ICC) and platelet-derived growth factor receptor alpha-positive (PDGFRα(+)) cells generate pacemaker activity throughout the gastrointestinal (GI) tract and also transduce enteric motor nerve signals and mechanosensitivity to adjacent SMCs. ICC and PDGFRα(+) cells are electrically coupled to SMCs possibly via gap junctions forming a multicellular functional syncytium termed the SIP syncytium. Cells that make up the SIP syncytium are highly specialized containing unique receptors, ion channels and intracellular signaling pathways that regulate the excitability of GI muscles. The unique role of these cells in coordinating GI motility is evident by the altered motility patterns in animal models where interstitial cell networks are disrupted. Although considerable advances have been made in recent years on our understanding of the roles of these cells within the SIP syncytium, the full physiological functions of these cells and the consequences of their disruption in GI muscles have not been clearly defined. This review gives a synopsis of the history of interstitial cell discovery and highlights recent advances in structural, molecular expression and functional roles of these cells in the GI tract.
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Affiliation(s)
- Peter J Blair
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV, USA; and
| | - Poong-Lyul Rhee
- Division of Gastroenterology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV, USA; and
| | - Sean M Ward
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV, USA; and
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Blair PJ, Rhee PL, Sanders KM, Ward SM. The significance of interstitial cells in neurogastroenterology. J Neurogastroenterol Motil 2014. [PMID: 24948131 DOI: 10.5056/jnm140] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Smooth muscle layers of the gastrointestinal tract consist of a heterogeneous population of cells that include enteric neurons, several classes of interstitial cells of mesenchymal origin, a variety of immune cells and smooth muscle cells (SMCs). Over the last number of years the complexity of the interactions between these cell types has begun to emerge. For example, interstitial cells, consisting of both interstitial cells of Cajal (ICC) and platelet-derived growth factor receptor alpha-positive (PDGFRα(+)) cells generate pacemaker activity throughout the gastrointestinal (GI) tract and also transduce enteric motor nerve signals and mechanosensitivity to adjacent SMCs. ICC and PDGFRα(+) cells are electrically coupled to SMCs possibly via gap junctions forming a multicellular functional syncytium termed the SIP syncytium. Cells that make up the SIP syncytium are highly specialized containing unique receptors, ion channels and intracellular signaling pathways that regulate the excitability of GI muscles. The unique role of these cells in coordinating GI motility is evident by the altered motility patterns in animal models where interstitial cell networks are disrupted. Although considerable advances have been made in recent years on our understanding of the roles of these cells within the SIP syncytium, the full physiological functions of these cells and the consequences of their disruption in GI muscles have not been clearly defined. This review gives a synopsis of the history of interstitial cell discovery and highlights recent advances in structural, molecular expression and functional roles of these cells in the GI tract.
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Affiliation(s)
- Peter J Blair
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV, USA
| | - Poong-Lyul Rhee
- Division of Gastroenterology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV, USA
| | - Sean M Ward
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV, USA
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Tanahashi Y, Ichimura Y, Kimura K, Matsuyama H, Iino S, Komori S, Unno T. Cholinergic neuromuscular transmission mediated by interstitial cells of Cajal in the myenteric layer in mouse ileal longitudinal smooth muscles. Naunyn Schmiedebergs Arch Pharmacol 2013; 387:377-88. [PMID: 24322587 DOI: 10.1007/s00210-013-0944-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 11/21/2013] [Indexed: 01/15/2023]
Abstract
To elucidate the roles played by the interstitial cells of Cajal in the myenteric layer (ICC-MY) in cholinergic neuromuscular transmission, we recorded mechanical and electrical activities in response to electrical field stimulation (EFS) of the ileal longitudinal muscle strips from WBB6F1-W/W(V) (W/W(V)) mutant mice, that lacked ICC-MY and compared with those in WBB6F1-+/+ (+/+) control mice. In +/+ muscle strips, EFS induced phasic contractions, which were abolished or strongly attenuated by atropine or tetrodotoxin. In W/W(V) preparations, EFS induced similar phasic contractions, but the cholinergic component was smaller than that in +/+ strips. This was despite of the fact that the contractions because of exogenous applications of carbachol and high K(+) solution in W/W(V) strips were comparable to or rather greater than those in the +/+ preparations. EFS induced atropine-sensitive excitatory junction potentials (EJPs) in the +/+ longitudinal smooth muscle cells but not in W/W(V) cells. In the presence of eserine, EFS induced atropine-sensitive EJPs in W/W(V) cells. These results suggest that ICC-MY mediate the cholinergic neuromuscular transmission in mouse ileal longitudinal smooth muscles. In addition, the other pathway in which ICC-MY are not involved can operate concomitantly.
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Affiliation(s)
- Yasuyuki Tanahashi
- Department of Animal Medical Sciences, Faculty of Life Sciences, Kyoto Sangyo University, Motoyama, Kamigamo, Kita-Ku, Kyoto, 603-8555, Japan,
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13
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Koh SD, Rhee PL. Ionic Conductance(s) in Response to Post-junctional Potentials. J Neurogastroenterol Motil 2013; 19:426-32. [PMID: 24199003 PMCID: PMC3816177 DOI: 10.5056/jnm.2013.19.4.426] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 08/28/2013] [Accepted: 08/30/2013] [Indexed: 01/29/2023] Open
Abstract
The gastrointestinal motility is regulated by extrinsic and intrinsic neural regulation. Intrinsic neural pathways are controlled by sensory input, inter-neuronal relay and motor output. Enteric motor neurons release many transmitters which affect post-junctional responses. Post-junctional responses can be excitatory and inhibitory depending on neurotransmitters. Excitatory neurotransmitters induce depolarization and contraction. In contrast, inhibitory neurotransmitters hyperpolarize and relaxe the gastrointestinal smooth muscle. Smooth muscle syncytium is composed of smooth muscle cells, interstitial cells of Cajal and platelet-derived growth factor receptor α-positive (PDGFRα(+)) cells (SIP syncytium). Specific expression of receptors and ion channels in these cells can be affected by neurotransmitters. In recent years, molecular reporter expression techniques are able to study the properties of ion channels and receptors in isolated specialized cells. In this review, we will discuss the mechanisms of ion channels to interpret the post-junctional responses in the gastrointestinal smooth muscles.
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Affiliation(s)
- Sang Don Koh
- Department of Physiology and Cell Biology, University of Nevada, School of Medicine, Reno, NV, USA
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14
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Tanahashi Y, Waki N, Unno T, Matsuyama H, Iino S, Kitazawa T, Yamada M, Komori S. Roles of M2 and M3 muscarinic receptors in the generation of rhythmic motor activity in mouse small intestine. Neurogastroenterol Motil 2013; 25:e687-97. [PMID: 23889852 DOI: 10.1111/nmo.12194] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 06/26/2013] [Indexed: 02/08/2023]
Abstract
BACKGROUND The roles of M2 and M3 muscarinic receptor subtypes in the regulation of gut motor activity were investigated. METHODS We simultaneously recorded changes in the intraluminal pressure (IP) and longitudinal tension (LT) in small intestinal segments from M2 or M3 receptor knockout (KO) and wild-type (WT) mice. KEY RESULTS In the WT preparations, luminal distension induced a continuous rhythmic contractile activity that was characterized by synchronous rises in IP and LT, occurring periodically at a constant interval. Tetrodotoxin completely abolished the response, whereas atropine either abolished or attenuated it. In the majority of the M2 KO preparations, however, no rhythmic activity was observed in response to the luminal distention, even though networks of enteric neurons and interstitial cells of Cajal (ICC) seemed to be intact. Where rhythmic activity did occur in M2 KO preparations, it was atropine resistant. In the M3 KO preparations, the IP and LT were synchronously changed by the luminal distention, but the changes occurred at irregular intervals. The W/W(v) mutant preparations, which lack ICC in the myenteric plexus (ICC-MY), showed results similar to those of the M3 KO preparations. In some of the M2 /M3 double-KO preparations, rhythmic activity was not observed, but in the others, an atropine-resistant rhythmicity appeared. CONCLUSIONS & INFERENCES These results suggest that M2 and M3 muscarinic receptors differentially regulate the intestinal motor activity: M2 receptors play an essential role in the generation of rhythmic motor activity, and M3 receptors have a modulatory role in controlling the periodicity of the rhythmic activity together with the ICC-MY.
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Affiliation(s)
- Y Tanahashi
- Department of Animal Medical Sciences, Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan
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15
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Hübsch M, Neuhuber WL, Raab M. Muscarinic acetylcholine receptors in the mouse esophagus: focus on intraganglionic laminar endings (IGLEs). Neurogastroenterol Motil 2013; 25:e560-73. [PMID: 23742744 DOI: 10.1111/nmo.12161] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Accepted: 05/04/2013] [Indexed: 02/08/2023]
Abstract
BACKGROUND IGLEs represent the only low-threshold vagal mechanosensory terminals in the tunica muscularis of the esophagus. Previously, close relationships of vesicular glutamate transporter 2 (VGLUT2) immunopositive IGLEs and cholinergic varicosities suggestive for direct contacts were described in almost all mouse esophageal myenteric ganglia. Possible cholinergic influence on IGLEs requires specific acetylcholine receptors. In particular, the occurrence and location of neuronal muscarinic acetylcholine receptors (mAChR) in the esophagus were not yet characterized. METHODS This study aimed at specifying relationships of VGLUT2 immunopositive IGLEs and vesicular acetylcholine transporter (VAChT)-immunopositive varicosities using pre-embedding electron microscopy and the location of mAChR1-3 (M1-3) within esophagus and nodose ganglia using multilabel immunofluorescence and retrograde tracing. KEY RESULTS Electron microscopy confirmed synaptic contacts between cholinergic varicosities and IGLEs. M1- and M2-immunoreactivities (-iry; -iries) were colocalized with VGLUT2-iry in subpopulations of IGLEs. Retrograde Fast Blue tracing from the esophagus showed nodose ganglion neurons colocalizing tracer and M2-iry. M1-3-iries were detected in about 80% of myenteric ganglia and in about 67% of myenteric neurons. M1- and M2-iry were present in many fibers and varicosities within myenteric ganglia. Presynaptic M2-iry was detected in all, presynaptic M3-iry in one-fifth of motor endplates of striated esophageal muscles. M1-iry could not be detected in motor endplates of the esophagus, but in sternomastoid muscle. CONCLUSIONS & INFERENCES Acetylcholine probably released from varicosities of both extrinsic and intrinsic origin may influence a subpopulation of esophageal IGLEs via M2 and M1-receptors.
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Affiliation(s)
- M Hübsch
- Institute of Anatomy I, University of Erlangen-Nuremberg, Erlangen, Germany
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16
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Abstract
Interstitial cells of Cajal (ICCs) are a kind of cells mainly found in the gastrointestinal tract as pacemaker and signal transduction cells. They have a close connection with muscular cells and terminal neurons and can stimulate and promote gastrointestinal motility. With the help of electron microscopes, we can clearly recognize their distribution and inner structure. C-kit protein is expressed by ICCs. Besides, many disorders of gastrointestinal motility are related to ICCs. In recent years, many scholars have found the trace of ICCs in different organs such as the gastrointestinal tract, biliary tract, bladder, and uterus, and they have tried to state the relationship between abnormal ICCs and some diseases. This article will review the progress in research of ICCs in terms of their origin, morphology, receptors, function, and related diseases.
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Abstract
Muscarinic agonists and antagonists are used to treat a handful of gastrointestinal (GI) conditions associated with impaired salivary secretion or altered motility of GI smooth muscle. With regard to exocrine secretion, the major muscarinic receptor expressed in salivary, gastric, and pancreatic glands is the M₃ with a small contribution of the M₁ receptor. In GI smooth muscle, the major muscarinic receptors expressed are the M₂ and M₃ with the M₂ outnumbering the M₃ by a ratio of at least four to one. The antagonism of both smooth muscle contraction and exocrine secretion is usually consistent with an M₃ receptor mechanism despite the major presence of the M₂ receptor in smooth muscle. These results are consistent with the conditional role of the M₂ receptor in smooth muscle. That is, the contractile role of the M₂ receptor depends on that of the M₃ so that antagonism of the M₃ receptor eliminates the response of the M₂. The physiological roles of muscarinic receptors in the GI tract are consistent with their known signaling mechanisms. Some so-called tissue-selective M₃ antagonists may owe their selectivity to a highly potent interaction with a nonmuscarinic receptor target.
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Xu WD, Jiang X, Lan L, Wang CH, Tong HX, Wang BX. Long-term culture and cryopreservation of interstitial cells of Cajal. Scand J Gastroenterol 2012; 47:89-98. [PMID: 22050097 DOI: 10.3109/00365521.2011.627445] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE Interstitial cells of Cajal (ICCs) in the gastrointestinal tract generate and propagate slow waves and mediate neuromuscular neurotransmission. Damage to ICCs has been described in several gastrointestinal motor disorders, and although many studies have examined ICCs in culture, they have been largely limited to freshly dissociated cells or short-term cultures. An efficient and reliable method to establish a source of ICCs is much needed. The aim of this study was to investigate methods for culturing, subculturing, cryopreservation, and recovery of ICCs. METHODS ICCs were derived from intestinal segments of domestic rabbits, and immunohistochemistry for c-Kit was used to identify ICCs in culture and after recovery. Recovered ICCs were also examined for motilin receptor expression. RESULTS Optimal conditions for ICC culture and cryopreservation were based on cell growth curves and MTT assay. On the basis of these findings, recovered cells were cultured for 7 days and then sorted via flow cytometry based on c-Kit immunoreactivity. The percent of c-Kit positive cells was 64.3%, and the number of ICCs sorted was 6.7 × 10(5). Reverse-transcription polymerase chain reaction and western blotting verified motilin receptor expression in c-Kit-positive ICCs. CONCLUSIONS This is the first study to describe the culture, passage, and recovery of ICCs and to show motilin receptor expression. Our results suggest that ICCs play an important role, at least in some species, in initiating the migrating myoelectric complex induced by motilin.
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Affiliation(s)
- Wen-Da Xu
- Department of Pediatrics, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shanxi Province, China
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19
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Forsgren S, Alfredson H, Bjur D, Rantapää-Dahlqvist S, Norrgård O, Dalén T, Danielson P. Novel information on the non-neuronal cholinergic system in orthopedics provides new possible treatment strategies for inflammatory and degenerative diseases. Orthop Rev (Pavia) 2011; 1:e11. [PMID: 21808665 PMCID: PMC3143960 DOI: 10.4081/or.2009.e11] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Revised: 06/23/2009] [Accepted: 06/26/2009] [Indexed: 01/14/2023] Open
Abstract
Anti-cholinergic agents are used in the treatment of several pathological conditions. Therapy regimens aimed at up-regulating cholinergic functions, such as treatment with acetylcholinesterase inhibitors, are also currently prescribed. It is now known that not only is there a neuronal cholinergic system but also a non-neuronal cholinergic system in various parts of the body. Therefore, interference with the effects of acetylcholine (ACh) brought about by the local production and release of ACh should also be considered. Locally produced ACh may have proliferative, angiogenic, wound-healing, and immunomodulatory functions. Interestingly, cholinergic stimulation may lead to anti-inflammatory effects. Within this review, new findings for the locomotor system of a more widespread non-neuronal cholinergic system than previously expected will be discussed in relation to possible new treatment strategies. The conditions discussed are painful and degenerative tendon disease (tendinopathy/tendinosis), rheumatoid arthritis, and osteoarthritis.
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Affiliation(s)
- Sture Forsgren
- Dept. of Integrative Medical Biology, Anatomy, Umeå University, Umeå, Sweden
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20
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Zhang RX, Wang XY, Chen D, Huizinga JD. Role of interstitial cells of Cajal in the generation and modulation of motor activity induced by cholinergic neurotransmission in the stomach. Neurogastroenterol Motil 2011; 23:e356-71. [PMID: 21781228 DOI: 10.1111/j.1365-2982.2011.01753.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Interstitial cells of Cajal (ICC) are intimately linked to the enteric nervous system and a better understanding of the interactions between the two systems is going to advance our understanding of gut motor control. The objective of the present study was to investigate the role of ICC in the generation of gastric motor activity induced by cholinergic neurotransmission. METHODS Gastric motor activity was evoked through activation of intrinsic cholinergic neural activity, in in vitro muscle strips by electrical field stimulation, in the in vitro whole stomach by distension and in vivo by fluoroscopy after gavaging the stomach with barium sulfate. The cholinergic activity was assessed as that component of the effect of the stimulus that was sensitive to atropine. These experiments were carried out in wild-type and Ws/Ws rats that have few intramuscular ICC (ICC-IM) in the stomach. KEY RESULTS Under all three experimental conditions, cholinergic activity was prominent in both wild-type and W mutant rats providing evidence against the hypothesis that cholinergic neurotransmission to smooth muscle is primarily mediated by ICC-IM. Strong cholinergic activity in Ws/Ws rats was not due to upregulation of muscarinic receptors in ICC but possibly in smooth muscle of the antrum. CONCLUSIONS & INFERENCES Pacemaker ICC play a prominent role in the expression of motor activity induced by cholinergic activity and our data suggest that cholinergic neurotransmission to ICC affects the pacemaker frequency.
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Affiliation(s)
- R-X Zhang
- Department of Medicine, Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, ON, Canada
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Huizinga JD, Martz S, Gil V, Wang XY, Jimenez M, Parsons S. Two independent networks of interstitial cells of cajal work cooperatively with the enteric nervous system to create colonic motor patterns. Front Neurosci 2011; 5:93. [PMID: 21833164 PMCID: PMC3153851 DOI: 10.3389/fnins.2011.00093] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2011] [Accepted: 07/13/2011] [Indexed: 12/12/2022] Open
Abstract
Normal motility of the colon is critical for quality of life and efforts to normalize abnormal colon function have had limited success. A better understanding of control systems of colonic motility is therefore essential. We report here a hypothesis with supporting experimental data to explain the origin of rhythmic propulsive colonic motor activity induced by general distention. The theory holds that both networks of interstitial cells of Cajal (ICC), those associated with the submuscular plexus (ICC-SMP) and those associated with the myenteric plexus (ICC-MP), orchestrate propagating contractions as pacemaker cells in concert with the enteric nervous system (ENS). ICC-SMP generate an omnipresent slow wave activity that causes propagating but non-propulsive contractions ("rhythmic propagating ripples") enhancing absorption. The ICC-MP generate stimulus-dependent cyclic depolarizations propagating anally and directing propulsive activity ("rhythmic propulsive motor complexes"). The ENS is not essential for both rhythmic motor patterns since distention and pharmacological means can produce the motor patterns after blocking neural activity, but it supplies the primary stimulus in vivo. Supporting data come from studies on segments of the rat colon, simultaneously measuring motility through spatiotemporal mapping of video recordings, intraluminal pressure, and outflow measurements.
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Affiliation(s)
- Jan D Huizinga
- Department of Medicine, Farncombe Family Digestive Health Research Institute, McMaster University Hamilton, ON, Canada
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22
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Rocha MS, Herbella FA, Del Grande JC, Ferreira AT, Tahan C, Patti MG. Effects of ursodeoxycholic acid in esophageal motility and the role of the mucosa. An experimental study. Dis Esophagus 2011; 24:291-4. [PMID: 21087343 DOI: 10.1111/j.1442-2050.2010.01137.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Esophageal motor abnormalities are frequently found in patients with gastroesophageal reflux disease. The role of bile in reflux-induced dysmotility is still elusive. Furthermore, it is questionable weather mucosal or muscular stimulation leads to motor dysfunction. The aims of this study were to analyze (i) the effect of bile in the amplitude of esophageal contractions; and (ii) the effect of mucosal versus muscular stimulation. Eighteen guinea pig esophagi were isolated, and its contractility assessed with force transducers. Three groups were studied. In group A (n= 6), the entire esophagus was incubated in 100 µmL ursodeoxycholic acid for 1 hour; in group B (n= 6) the mucosal layer was removed and the muscular layer incubated in 100 µmL ursodeoxycholic acid for 1 hour; and in group C (n= 6) (control group) the entire esophagus was incubated in saline solution. In all groups, five sequential contractions induced by 40 mm KCl spaced by 5 minutes were measured before and after incubation. Contractions amplitudes before incubation were 1.319 g, 0.306 g, and 1.795 g, for groups A, B, and C, respectively. There were no differences between groups A and C (P= 0.633), but there were differences between groups A and B (P= 0.039), and B and C (P= 0.048). After incubation amplitude of contraction were 0.709 g, 0.278 g, and 1.353 g for groups A, B, and C, respectively. Only group A showed difference when pre and post-stimulation amplitudes were compared (P= 0.030). Our results show that (i) bile exposure decreases esophageal contraction amplitude; and (ii) the esophageal mucosa seems to play an important role in esophageal motility.
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Affiliation(s)
- M S Rocha
- Department of Surgery, Escola Paulista de Medicina, Federal University of Sao Paulo, Sao Paulo, Brazil
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23
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Chanda S, Song J, Rezk P, Sabnekar P, Doctor BP, Sciuto AM, Nambiar MP. Gastrointestinal acetylcholinesterase activity following endotracheal microinstillation inhalation exposure to sarin in guinea pigs. Chem Biol Interact 2010; 187:309-11. [PMID: 20227400 DOI: 10.1016/j.cbi.2010.03.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Revised: 03/01/2010] [Accepted: 03/05/2010] [Indexed: 10/19/2022]
Abstract
The goal of this study was to assess acetylcholinesterase (AChE) inhibition at different regions of the gastrointestinal (GI) tract following inhalation exposure to nerve agent sarin. Seven major regions of the GI tract were removed from saline control animals (n=3) and 677.4 mg/m(3) sarin-exposed animals at 4h (n=4) and 24h (n=4) post-exposure. AChE activity was determined in blood and homogenized tissue supernatant by specific Ellman's assay using Iso-OMPA, a BChE inhibitor, and expressed as activity/optical density of hemoglobin for blood and activity/mg protein for tissues. Our data showed that the AChE activity was significantly decreased for groups both 4h and 24h post-sarin exposure. Among the seven chosen regions of the guinea pig GI tract, duodenum showed the highest AChE activity in control animals. The AChE activity was significantly decreased in the stomach (p=0.03), duodenum (p=0.029), jejunum (p=0.006), and ileum (p=0.006) 4h following sarin exposure. At 24h post-sarin exposure the AChE activity of duodenum (p=0.029) and ileum (p=0.006) was significantly inhibited. Esophagus showed no inhibition following sarin exposure at both 4h and 24h groups. These results suggest that the AChE activity is different in different regions of the GI tract and highest levels of AChE inhibition following sarin exposure were seen in regions exhibiting higher overall AChE activity and cholinergic function.
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Affiliation(s)
- Soma Chanda
- Division of Brain Dysfunction and Blast Injury, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA
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Shakirova Y, Mori M, Ekman M, Erjefält J, Uvelius B, Swärd K. Human urinary bladder smooth muscle is dependent on membrane cholesterol for cholinergic activation. Eur J Pharmacol 2010; 634:142-8. [PMID: 20176011 DOI: 10.1016/j.ejphar.2010.02.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Revised: 12/09/2009] [Accepted: 02/09/2010] [Indexed: 01/18/2023]
Abstract
Voiding is mediated by muscarinic receptors in urinary bladder smooth muscle cells. Lipid rafts and caveolae are cholesterol enriched membrane domains that modulate the activity of G protein-coupled receptors and second messenger systems. Conflicting findings regarding sensitivity of muscarinic signalling to cholesterol desorption, which perturbs lipid rafts and caveolae, have been reported, and no study has used human urinary bladder. Here, the dependence of human bladder muscarinic receptor signalling on plasma membrane cholesterol was examined. Nerve-mediated contraction, elicited by electrical field stimulation of human bladder strips, was impaired by desorption of cholesterol using methyl-beta-cyclodextrin, and the concentration-response curve for the muscarinic agonist carbachol was right-shifted. No effect of cholesterol desorption was observed in rat, and in mouse increased maximum contraction was seen. Expression of caveolin-1, PLCbeta1 and M3 muscarinic receptors did not differ between species in a manner that would explain the differential sensitivity to cholesterol desorption. In human bladder, threshold depolarisation eliminated the difference between cyclodextrin-treated and control preparations. Contraction elicited by depolarisation per se was not affected. M3 muscarinic receptors appeared clustered along plasma membrane profiles as shown by immunohistochemical staining of human bladder, but no redistribution in association with cholesterol reduction was seen. Thus, muscarinic receptor-induced contraction of the urinary bladder exhibits species-specific differences in its sensitivity to cholesterol desorption suggesting differential roles of lipid rafts/caveolae in muscarinic receptor signalling between species.
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Affiliation(s)
- Yulia Shakirova
- Department of Experimental Medical Science, Lund University, Biomedical Centre, BMC D12, SE-221 84 Lund, Sweden.
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Garcia-Lopez P, Garcia-Marin V, Martínez-Murillo R, Freire M. Updating old ideas and recent advances regarding the Interstitial Cells of Cajal. ACTA ACUST UNITED AC 2009; 61:154-69. [PMID: 19520112 DOI: 10.1016/j.brainresrev.2009.06.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2009] [Revised: 05/30/2009] [Accepted: 06/01/2009] [Indexed: 12/11/2022]
Abstract
Since their discovery by Cajal in 1889, the Interstitial Cells of Cajal (ICC) have generated much controversy in the scientific community. Indeed, the nervous, muscle or fibroblastic nature of the ICC has remained under debate for more than a century, as has their possible physiological function. Cajal and his colleagues considered them to be neurons, while contemporary histologists like Kölliker and Dogiel categorized these cells as fibroblasts. More recently, the role of ICC in the origin of slow-wave peristaltism has been elucidated, and several studies have shown that they participate in neurotransmission (intercalation theory). The fact that ICC assemble in the circular muscular layer and that they originate from cells which emerge from the ventral neural tube (VENT cells), a source of neurons, glia and ICC precursors other than the neural crest, suggests a neural origin for this particular subset of ICC. The discovery that ICC express the Kit protein, a type III tyrosine kinase receptor encoded by the proto-oncogene c-kit, has helped better understand their physiological role and implication in pathological conditions. Gleevec, a novel molecule designed to inhibit the mutant activated version of c-Kit receptors, is the drug of choice to treat the so-called gastrointestinal stromal tumours (GIST), the most common non-epithelial neoplasm of the gastrointestinal tract. Here we review Cajal's original contributions with the aid of unique images taken from Cajal's histological slides (preserved at the Cajal Museum, Cajal Institute, CSIC). In addition, we present a historical review of the concepts associated with this particular cell type, emphasizing current data that has advanced our understanding of the role these intriguing cells fulfil.
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Affiliation(s)
- P Garcia-Lopez
- Cajal Institute, CSIC, Avda Doctor Arce 37, 28002 - Madrid, Spain
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26
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IINO S, HORIGUCHI K, NOJYO Y, WARD SM, SANDERS KM. Interstitial cells of Cajal contain signalling molecules for transduction of nitrergic stimulation in guinea pig caecum. Neurogastroenterol Motil 2009; 21:542-50, e12-3. [PMID: 19175750 PMCID: PMC4793909 DOI: 10.1111/j.1365-2982.2008.01236.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Nitric oxide (NO) is an inhibitory signalling molecule in the gastrointestinal (GI) tract that is released from neurons and from leucocytes during inflammation. NO stimulates soluble guanylate cyclase (sGC), elevates cyclic guanosine 3',5'-monophospate (cGMP), and subsequently activates cGMP-dependent protein kinase (PKG). Targets for NO in the guinea pig caecum were investigated by characterizing the cellular distribution of sGC, cGMP and PKG. Immunoreactivity for both isoforms of sGC, sGCalpha1 and sGCbeta1, was observed in the interstitial cells of Cajal (ICC) and enteric neurons in the tunica muscularis. Double labelling with anti-Kit and anti-sGC antibodies showed sGCalpha1 and sGCbeta1-like immunoreactivity (LI) in almost all intramuscular (IM) and myenteric ICC. Neuronal processes with neuronal NO synthase were closely apposed to ICC expressing sGC-LI. Cells with sGC-LI possessed ultrastructural features of ICC-IM: caveolae, close association with nerve bundles and contacts with smooth muscle cells (SMC). Sodium nitroprusside, added with the phosphodiesterase inhibitors (3-isobutyl-1-methylxanthine and zaprinast), enhanced cGMP-LI in almost all ICC and in some enteric neurons. Nerve stimulation also increased cGMP-LI in ICC and enteric neurons. In contrast, no resolvable increase in cGMP-LI was observed in any cells when the sGC inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one was present. ICC and SMC also expressed PKG type I-LI. These data show that ICC express the downstream signalling molecules necessary to transduce nitrergic signals and activate inhibitory pathways and thus are primary targets for NO released from neurons and other cells in the GI tract.
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Affiliation(s)
- S. IINO
- Department of Morphological and Physiological Sciences, University of Fukui Faculty of Medical Sciences, Eiheiji, Fukui, Japan
| | - K. HORIGUCHI
- Department of Morphological and Physiological Sciences, University of Fukui Faculty of Medical Sciences, Eiheiji, Fukui, Japan
| | - Y. NOJYO
- Department of Morphological and Physiological Sciences, University of Fukui Faculty of Medical Sciences, Eiheiji, Fukui, Japan
| | - S. M. WARD
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV, USA
| | - K. M. SANDERS
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV, USA
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Monro RL, Bornstein JC, Bertrand PP. Synaptic transmission from the submucosal plexus to the myenteric plexus in Guinea-pig ileum. Neurogastroenterol Motil 2008; 20:1165-73. [PMID: 18643893 DOI: 10.1111/j.1365-2982.2008.01157.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Stimulation of the myenteric plexus results in activation of submucosal neurons and dilation of arterioles, one way that motility and secretion can be coupled together. The present study aimed to examine the converse, whether myenteric neurons receive synaptic input from the submucosal plexus (SMP). Intracellular recordings were made from guinea-pig ileal myenteric neurons while the SMP was electrically stimulated. Of the 29 neurons studied (13 S and 16 AH neurons), stimulation of the SMP evoked a synaptic potential in only seven cells, or 24% of neurons. When the SMP was situated oral to the myenteric plexus, 4 of 13 (31%) myenteric neurons had synaptic input. When it was situated circumferential, 2 of 8 (25%) had input, and when the SMP was situated anal 1 of 8 (13%) had input. Overall, 5 of the 13 (38%) S neurons responded with fast excitatory post-synaptic potentials (EPSPs), one of which also showed a slow EPSP, while 2 of the 16 (13%) AH neurons responded with a slow EPSP. This study indicates that the synaptic input from the SMP to myenteric neurons is relatively sparse. Whether this input is less important than the myenteric to submucosal input or simply represents a more selective form of control is unknown.
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Affiliation(s)
- R L Monro
- Department of Physiology, University of Melbourne, Parkville, Australia
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Wu Q, Harada N, Nakamura A, Yoshida M, Mawatari K, Hattori A, Li Q, Shimohata T, Yinhua, Lian X, Nakano M, Hosaka T, Takahashi A, Nakaya Y. NO-1886, a lipoprotein lipase activator, attenuates contraction of rat intestinal ring preparations. THE JOURNAL OF MEDICAL INVESTIGATION 2008; 55:61-70. [PMID: 18319547 DOI: 10.2152/jmi.55.61] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Various intestinal symptoms or diseases are closely associated with intestinal motility, which may be altered by metabolic disturbances associated with diabetes and obesity. It is therefore important that drugs used in the treatment of metabolic disorders should not have any adverse effects on the intestine. In the present study, we examined whether [4-(4-bromo-2-cyano-phenylcarbamoyl)-benzyl]-phosphonic acid diethyl ester (NO-1886), a lipoprotein lipase activator with anti-diabetic and/or anti-obese activity, affects stimulant-induced intestinal contractility. Administration of NO-1886 to intestinal ring preparations of ileum, rectum and colon isolated from Wistar rats attenuated or relaxed contraction induced by a high K+ environment or acetylcholine (ACh). This effect of NO-1886 was dependent on extracellular Ca(2+) and intracellular myosin light chain kinase activity. Our results also showed that ACh-induced colonic contraction was significantly higher in the obese Otsuka Long-Evans Tokushima Fatty (OLETF) than in the non-obese Long-Evans Tokushima Otsuka (LETO) rats. The hypercontractility observed in the colons of OLETF rats occurred concomitantly with an elevation in muscarinic M3 ACh receptor protein levels. Administration of NO-1886 attenuated the obesity-induced hypercontractility of the colonic rings of OLETF rats. Thus, intestinal contractile system would be a novel pharmacological target of the lipoprotein lipase activator NO-1886.
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Affiliation(s)
- Qishisan Wu
- Department of Nutrition and Metabolism, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan
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Immunohistochemical localisation of pre-synaptic muscarinic receptor subtype-2 (M2r) in the enteric nervous system of guinea-pig ileum. Cell Tissue Res 2008; 332:37-48. [DOI: 10.1007/s00441-007-0533-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2007] [Accepted: 10/01/2007] [Indexed: 12/31/2022]
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Iino S, Horiguchi K, Nojyo Y. Interstitial cells of Cajal are innervated by nitrergic nerves and express nitric oxide-sensitive guanylate cyclase in the guinea-pig gastrointestinal tract. Neuroscience 2008; 152:437-48. [PMID: 18280665 DOI: 10.1016/j.neuroscience.2007.12.044] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2007] [Revised: 11/11/2007] [Accepted: 12/12/2007] [Indexed: 02/07/2023]
Abstract
Nitric oxide (NO) is a major signaling molecule in the gastrointestinal tract, and released NO inhibits muscular contraction. The actions of NO are mediated by stimulation of soluble guanylate cyclase (sGC, NO-sensitive GC) and a subsequent increase in cGMP concentration. To elucidate NO targets in the gastrointestinal musculature, we investigated the immunohistochemical localization of the beta1 and alpha1 subunits of sGC and the distribution of neuronal NO synthase (nNOS) -containing nerves in the guinea-pig gastrointestinal tract. Distinct immunoreactivity for sGCbeta1 and sGCalpha1 was observed in the interstitial cells of Cajal (ICC), fibroblast-like cells (FLC) and enteric neurons in the musculature. Double immunohistochemistry using anti-c-Kit antibody and anti-sGCbeta1 antibody revealed sGCbeta1 immunoreactivity in almost all intramuscular ICC throughout the entire gastrointestinal tract. Immunoelectron microscopy revealed that sGCbeta1-immunopositive cells possessed some of the criteria for intramuscular ICC: presence of caveolae; frequently associated with nerve bundles; and close contact with smooth muscle cells. sGCbeta1-immunopositive ICC were closely apposed to nNOS-containing nerve fibers in the muscle layers. Immunohistochemical and immunoelectron microscopical observations revealed that FLC in the musculature also showed sGCbeta1 immunoreactivity. FLC were often associated with nNOS-immunopositive nerve fibers. In the myenteric layer, almost all myenteric ganglia contained nNOS-immunopositive nerve cells and were surrounded by myenteric ICC and FLC. Myenteric ICC in the large intestine and FLC in the entire gastrointestinal tract showed sGCbeta1 immunoreactivity in the myenteric layer. Smooth muscle cells in the stomach and colon showed weak sGCbeta1 immunoreactivity, and those in the muscularis mucosae and vasculature also showed evident immunoreactivity. These data suggest that ICC are primary targets for NO released from nNOS-containing enteric neurons, and that some NO signals are received by FLC and smooth muscle cells in the gastrointestinal tract.
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Affiliation(s)
- S Iino
- Department of Morphological and Physiological Sciences, University of Fukui Faculty of Medical Sciences, Eiheiji, Fukui 910-1193, Japan.
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Jönsson M, Norrgård O, Forsgren S. Presence of a marked nonneuronal cholinergic system in human colon: study of normal colon and colon in ulcerative colitis. Inflamm Bowel Dis 2007; 13:1347-56. [PMID: 17663429 DOI: 10.1002/ibd.20224] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
BACKGROUND The body has not only a neuronal but also a nonneuronal cholinergic system. Both systems are likely to be very important, particularly in inflammatory conditions. The patterns and importance of the nonneuronal cholinergic system in patients with ulcerative colitis (UC) are largely unknown. METHODS The colons of UC and non-UC patients were examined for expression patterns of choline acetyltransferase (ChAT), vesicular acetylcholine transporter (VAChT), and the muscarinic receptor of the M(2) subtype. RESULTS ChAT and VAChT immunoreactions and mRNA reactions for ChAT were detected in epithelial and endocrine cells, in cells in the lamina propria, and in blood vessel walls. Furthermore, a marked M(2) immunoreaction was noted for epithelium, blood vessel walls, and smooth musculature. ChAT and VAChT immunoreactions were significantly higher in endocrine and epithelial cells, respectively, in non-UC mucosa than in UC mucosa. On the other hand, there was a tendency toward higher M(2) levels in epithelium of UC patients. CONCLUSIONS There is a pronounced nonneuronal cholinergic system in the colon, which has previously been ignored when discussing cholinergic influences in UC. Furthermore, it is evident that certain changes in the nonneuronal cholinergic system occur in response to inflammation/derangement in UC. Cholinergic effects in the colon can be considered to be related not only to nerve-related effects but also to effects of acetylcholine from nonneuronal local cells. Thus, the recently discussed phenomenon of a "cholinergic antiinflammatory pathway" in the intestine may have a pronounced nonneuronal component.
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Affiliation(s)
- Maria Jönsson
- Department of Integrative Medical Biology, Anatomy, Umeå University, Umeå, Sweden.
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Takeuchi T, Tanaka K, Nakajima H, Matsui M, Azuma YT. M2 and M3 muscarinic receptors are involved in enteric nerve-mediated contraction of the mouse ileum: Findings obtained with muscarinic-receptor knockout mouse. Am J Physiol Gastrointest Liver Physiol 2007; 292:G154-64. [PMID: 17008557 DOI: 10.1152/ajpgi.00173.2006] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The involvement of muscarinic receptors in neurogenic responses of the ileum was studied in wild-type and muscarinic-receptor (M-receptor) knockout (KO) mice. Electrical field stimulation to the wild-type mouse ileum induced a biphasic response, a phasic and sustained contraction that was abolished by tetrodotoxin. The sustained contraction was prolonged for an extended period after the termination of electrical field stimulation. The phasic contraction was completely inhibited by atropine. In contrast, the sustained contraction was enhanced by atropine. Ileal strips prepared from M2-receptor KO mice exhibited a phasic contraction similar to that seen in wild-type mice and a sustained contraction that was larger than that in wild-type mice. In M3-receptor KO mice, the phasic contraction was smaller than that observed in wild-type mice. Acetylcholine exogenously administrated induced concentration-dependent contractions in strips isolated from wild-type, M2- and M3-receptor KO mice. However, contractions in M3-receptor KO mice shifted to the right. The sustained contraction was inhibited by capsaicin and neurokinin NK2 receptor antagonist, suggesting that it is mediated by substance P (SP). SP-induced contraction of M2-receptor KO mice did not differ from that of wild-type mice. SP immunoreactivity was located in enteric neurons, colocalized with M2 receptor immunoreactivity. These results suggest that atropine-sensitive phasic contraction is mainly mediated via the M3 receptor, and SP-mediated sustained contraction is negatively regulated by the M2 receptor at a presynaptic level.
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Affiliation(s)
- Tadayoshi Takeuchi
- Department of Veterinary Pharmacology, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai Osaka 599-8531, Japan.
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Iino S, Horiguchi K. Interstitial cells of cajal are involved in neurotransmission in the gastrointestinal tract. Acta Histochem Cytochem 2006; 39:145-53. [PMID: 17327901 PMCID: PMC1779949 DOI: 10.1267/ahc.06023] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2006] [Accepted: 10/18/2006] [Indexed: 12/12/2022] Open
Abstract
Interstitial cells of Cajal (ICC) are important cells which coordinate gastrointestinal motility. ICC express Kit receptor tyrosine kinase, and Kit immunohistochemistry reveals ICC morphology and distribution in the gastrointestinal musculature. ICC show a highly branched morphology and form unique networks. Myenteric ICC (ICC-MY) are located at the layer of the myenteric plexus and serve as electrical pacemakers. Intramuscular ICC (ICC-IM) and ICC in the deep muscular plexus (ICC-DMP) are distributed within the muscular layers, and are densely innervated by excitatory and inhibitory enteric motor neurons and in close contact with nerve terminals. Recent studies combined with morphological and functional techniques directly revealed that ICC-IM and ICC-DMP are mediators of enteric motor neuro-transmission. These types of ICC express several receptors for neurotransmitters such as acetylcholine and substance P and show responses to excitatory nerve stimulations. ICC also express receptive mechanisms for nitric oxide, which is an inhibitory neurotransmitter in the gastrointestinal tract. They can respond to nitrergic nerve stimulation by cyclic GMP production. Kit mutant mice lack ICC-IM and show attenuated postsynaptic responses after intrinsic nerve stimulation. These findings indicate the importance for ICC in neurotransmission in the gastrointestinal tract.
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Affiliation(s)
- Satoshi Iino
- Department of Anatomy, Faculty of Medical Sciences, University of Fukui, Eiheiji, Fukui 910–1193, Japan
- Correspondence to: Satoshi Iino, MD, PhD, Department of Anatomy, Faculty of Medical Sciences, University of Fukui, Eiheiji, Fukui 910–1193, Japan. E-mail:
| | - Kazuhide Horiguchi
- Department of Anatomy, Faculty of Medical Sciences, University of Fukui, Eiheiji, Fukui 910–1193, Japan
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McKay CM, Huizinga JD. Muscarinic regulation of ether-a-go-go-related gene K+ currents in interstitial cells of Cajal. J Pharmacol Exp Ther 2006; 319:1112-23. [PMID: 16946103 DOI: 10.1124/jpet.106.109322] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The interstitial cells of Cajal (ICC) of the myenteric plexus generate a set of currents that evoke a pacemaker potential that sets the initial conditions for the contraction frequency and duration of the electrically coupled intestinal musculature. The synapse-like contacts between ICC and myenteric motor nerves highlight the potential role of the enteric nervous system in regulating the pacemaking currents in ICC. The objective of the present study was to investigate muscarinic regulation of the ether-a-go-go-related gene (ERG) K(+) current. Immunoreactivity of the M(3) receptor (M(3)R) but not the M(2) receptor was detected on murine jejunal ICC-Auerbach's plexus (ICC-AP). The muscarinic agonist bethanechol reduced hyperpolarization-evoked peak ERG currents at -100 mV by 23 +/- 1% and increased both fast and slow time constants of deactivation, resulting in increased steady-state currents between -55 and -35 mV. Bethanechol also increased depolarization-evoked steady-state currents by 59 +/- 10% at -40 mV, whereas currents were decreased at potentials positive to 0 mV. The half-maximal voltage of activation was shifted 11.9 mV leftward. Interestingly, the time constant of activation increased only at -40 mV. Atropine prevented and 2 muM E4031 [1-[2-(6-methyl-2-pyridyl)-ethyl-4-(methylsulfonylaminobenzoyl)piperidine] inhibited bethanechol-affected currents. The effect of bethanechol was mimicked by protein kinase C (PKC) activation and diminished by PKC inhibition. Our results indicate that the ERG K(+) channel in ICC is affected by stimulation of muscarinic receptors, probably the M(3)R, via a PKC-dependent mechanism. Modulation of the ERG K(+) current in ICC-AP will affect the kinetics of pacemaking in the intestinal musculature.
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Affiliation(s)
- Catherine M McKay
- Intestinal Disease Research Program, McMaster University, Hamilton, Ontario, Canada
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