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Nozaki S, Hijioka M, Wen X, Iwashita N, Namba J, Nomura Y, Nakanishi A, Kitazawa S, Honda R, Kamatari YO, Kitahara R, Suzuki K, Inden M, Kitamura Y. Galantamine suppresses α-synuclein aggregation by inducing autophagy via the activation of α 7 nicotinic acetylcholine receptors. J Pharmacol Sci 2024; 156:102-114. [PMID: 39179329 DOI: 10.1016/j.jphs.2024.07.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2024] [Revised: 07/25/2024] [Accepted: 07/29/2024] [Indexed: 08/26/2024] Open
Abstract
Synucleinopathies, including Parkinson's disease and dementia with Lewy bodies, are neurodegenerative disorders characterized by the aberrant accumulation of α-synuclein (α-syn). Although no treatment is effective for synucleinopathies, the suppression of α-syn aggregation may contribute to the development of numerous novel therapeutic targets. Recent research revealed that nicotinic acetylcholine (nACh) receptor activation has neuroprotective effects and promotes the degradation of amyloid protein by activating autophagy. In an in vitro human-derived cell line model, we demonstrated that galantamine, the nAChR allosteric potentiating ligand, significantly reduced the cell number of SH-SY5Y cells with intracellular Lewy body-like aggregates by enhancing the sensitivity of α7-nAChR. In addition, galantamine promoted autophagic flux, and prevented the formation of Lewy body-resembled aggregates. In an in vivo synucleinopathy mouse model, the propagation of α-syn aggregation in the cerebral cortex was inhibited by galantamine administration for 90 days. These results suggest that α7-nAChR is expected to be a novel therapeutic target, and galantamine is a potential agent for synucleinopathies.
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Affiliation(s)
- Sora Nozaki
- Pharmacology and Neurobiology Laboratory, College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu, Shiga, 525-8577, Japan
| | - Masanori Hijioka
- Pharmacology and Neurobiology Laboratory, College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu, Shiga, 525-8577, Japan; Department of Neurocognitive Science, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan
| | - Xiaopeng Wen
- Pharmacology and Neurobiology Laboratory, College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu, Shiga, 525-8577, Japan.
| | - Natsumi Iwashita
- Pharmacology and Neurobiology Laboratory, College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu, Shiga, 525-8577, Japan
| | - Junya Namba
- Pharmacology and Neurobiology Laboratory, College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu, Shiga, 525-8577, Japan
| | - Yoshiaki Nomura
- Pharmacology and Neurobiology Laboratory, College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu, Shiga, 525-8577, Japan
| | - Aoi Nakanishi
- Pharmacology and Neurobiology Laboratory, College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu, Shiga, 525-8577, Japan
| | - Soichiro Kitazawa
- Laboratory of Structural Biology, College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu, Shiga, 525-8577, Japan
| | - Ryo Honda
- The United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan; Center for One Medicine Innovative Translational Research (COMIT), Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan
| | - Yuji O Kamatari
- The United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan; Center for One Medicine Innovative Translational Research (COMIT), Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan; Institute for Glyco-Core Research (iGCORE), Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Ryo Kitahara
- Laboratory of Structural Biology, College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu, Shiga, 525-8577, Japan
| | - Kenji Suzuki
- Laboratory of Molecular Medicinal Science, College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu, Shiga, 525-8577, Japan
| | - Masatoshi Inden
- Laboratory of Medical Therapeutics and Molecular Therapeutics, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu, 501-1196, Japan
| | - Yoshihisa Kitamura
- Pharmacology and Neurobiology Laboratory, College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu, Shiga, 525-8577, Japan.
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Zhang C, Burger RM. Cholinergic modulation in the vertebrate auditory pathway. Front Cell Neurosci 2024; 18:1414484. [PMID: 38962512 PMCID: PMC11220170 DOI: 10.3389/fncel.2024.1414484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Accepted: 06/06/2024] [Indexed: 07/05/2024] Open
Abstract
Acetylcholine (ACh) is a prevalent neurotransmitter throughout the nervous system. In the brain, ACh is widely regarded as a potent neuromodulator. In neurons, ACh signals are conferred through a variety of receptors that influence a broad range of neurophysiological phenomena such as transmitter release or membrane excitability. In sensory circuitry, ACh modifies neural responses to stimuli and coordinates the activity of neurons across multiple levels of processing. These factors enable individual neurons or entire circuits to rapidly adapt to the dynamics of complex sensory stimuli, underscoring an essential role for ACh in sensory processing. In the auditory system, histological evidence shows that acetylcholine receptors (AChRs) are expressed at virtually every level of the ascending auditory pathway. Despite its apparent ubiquity in auditory circuitry, investigation of the roles of this cholinergic network has been mainly focused on the inner ear or forebrain structures, while less attention has been directed at regions between the cochlear nuclei and midbrain. In this review, we highlight what is known about cholinergic function throughout the auditory system from the ear to the cortex, but with a particular emphasis on brainstem and midbrain auditory centers. We will focus on receptor expression, mechanisms of modulation, and the functional implications of ACh for sound processing, with the broad goal of providing an overview of a newly emerging view of impactful cholinergic modulation throughout the auditory pathway.
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Affiliation(s)
- Chao Zhang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, United States
| | - R. Michael Burger
- Department of Biological Sciences, Lehigh University, Bethlehem, PA, United States
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Strain MM, Conley NJ, Kauffman LS, Espinoza L, Fedorchak S, Martinez PC, Crook ME, Jalil M, Hodes GE, Abbott SB, Güler AD, Campbell JN, Boychuk CR. Dorsal motor vagal neurons can elicit bradycardia and reduce anxiety-like behavior. iScience 2024; 27:109137. [PMID: 38420585 PMCID: PMC10901094 DOI: 10.1016/j.isci.2024.109137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 12/16/2023] [Accepted: 02/01/2024] [Indexed: 03/02/2024] Open
Abstract
Cardiovagal neurons (CVNs) innervate cardiac ganglia through the vagus nerve to control cardiac function. Although the cardioinhibitory role of CVNs in nucleus ambiguus (CVNNA) is well established, the nature and functionality of CVNs in dorsal motor nucleus of the vagus (CVNDMV) is less clear. We therefore aimed to characterize CVNDMV anatomically, physiologically, and functionally. Optogenetically activating cholinergic DMV neurons resulted in robust bradycardia through peripheral muscarinic (parasympathetic) and nicotinic (ganglionic) acetylcholine receptors, but not beta-1-adrenergic (sympathetic) receptors. Retrograde tracing from the cardiac fat pad labeled CVNNA and CVNDMV through the vagus nerve. Using whole-cell patch-clamp, CVNDMV demonstrated greater hyperexcitability and spontaneous action potential firing ex vivo despite similar resting membrane potentials, compared to CVNNA. Chemogenetically activating DMV also caused significant bradycardia with a correlated reduction in anxiety-like behavior. Thus, DMV contains uniquely hyperexcitable CVNs and is capable of cardioinhibition and robust anxiolysis.
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Affiliation(s)
- Misty M. Strain
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, TX, USA
| | | | - Lily S. Kauffman
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Liliana Espinoza
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Stephanie Fedorchak
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, TX, USA
| | | | - Maisie E. Crook
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Maira Jalil
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Georgia E. Hodes
- School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Stephen B.G. Abbott
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Ali D. Güler
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - John N. Campbell
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Carie R. Boychuk
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, TX, USA
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA
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4
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Strain MM, Conley NJ, Kauffman LS, Espinoza L, Fedorchak S, Martinez PC, Crook ME, Jalil M, Hodes GE, Abbott SBG, Güler AD, Campbell JN, Boychuk CR. Dorsal Motor Vagal Neurons Can Elicit Bradycardia and Reduce Anxiety-Like Behavior. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.14.566855. [PMID: 38014247 PMCID: PMC10680764 DOI: 10.1101/2023.11.14.566855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Cardiovagal neurons (CVNs) innervate cardiac ganglia through the vagus nerve to control cardiac function. Although the cardioinhibitory role of CVNs in nucleus ambiguus (CVNNA) is well established, the nature and functionality of CVNs in dorsal motor nucleus of the vagus (CVNDMV) is less clear. We therefore aimed to characterize CVNDMV anatomically, physiologically, and functionally. Optogenetically activating cholinergic DMV neurons resulted in robust bradycardia through peripheral muscarinic (parasympathetic) and nicotinic (ganglionic) acetylcholine receptors, but not beta-1-adrenergic (sympathetic) receptors. Retrograde tracing from the cardiac fat pad labeled CVNNA and CVNDMV through the vagus nerve. Using whole cell patch clamp, CVNDMV demonstrated greater hyperexcitability and spontaneous action potential firing ex vivo despite similar resting membrane potentials, compared to CVNNA. Chemogenetically activating DMV also caused significant bradycardia with a correlated reduction in anxiety-like behavior. Thus, DMV contains uniquely hyperexcitable CVNs capable of cardioinhibition and robust anxiolysis.
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Affiliation(s)
- Misty M. Strain
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, TX
| | | | - Lily S. Kauffman
- Department of Biology, University of Virginia, Charlottesville, VA
| | - Liliana Espinoza
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, TX
| | - Stephanie Fedorchak
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, TX
| | | | - Maisie E. Crook
- Department of Biology, University of Virginia, Charlottesville, VA
| | - Maira Jalil
- Department of Biology, University of Virginia, Charlottesville, VA
| | - Georgia E. Hodes
- School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA
| | | | - Ali D. Güler
- Department of Biology, University of Virginia, Charlottesville, VA
| | - John N. Campbell
- Department of Biology, University of Virginia, Charlottesville, VA
| | - Carie R. Boychuk
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, TX
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO
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5
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Smith JEG, Ashton JL, Argent LP, Cheyne JE, Montgomery JM. Recording plasticity in neuronal activity in the rodent intrinsic cardiac nervous system using calcium imaging techniques. Front Synaptic Neurosci 2023; 15:1104736. [PMID: 37082542 PMCID: PMC10110955 DOI: 10.3389/fnsyn.2023.1104736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 03/20/2023] [Indexed: 04/22/2023] Open
Abstract
The intrinsic cardiac nervous system (ICNS) is composed of interconnected clusters of neurons called ganglionated plexi (GP) which play a major role in controlling heart rate and rhythm. The function of these neurons is particularly important due to their involvement in cardiac arrhythmias such as atrial fibrillation (AF), and previous work has shown that plasticity in GP neural networks could underpin aberrant activity patterns that drive AF. As research in this field increases, developing new techniques to visualize the complex interactions and plasticity in this GP network is essential. In this study we have developed a calcium imaging method enabling the simultaneous recording of plasticity in neuronal activity from multiple neurons in intact atrial GP networks. Calcium imaging was performed with Cal-520 AM labeling in aged spontaneously hypertensive rats (SHRs), which display both spontaneous and induced AF, and age-matched Wistar Kyoto (WKY) controls to determine the relationship between chronic hypertension, arrhythmia and GP calcium dynamics. Our data show that SHR GPs have significantly larger calcium responses to cholinergic stimulation compared to WKY controls, as determined by both higher amplitude and longer duration calcium responses. Responses were significantly but not fully blocked by hexamethonium, indicating multiple cholinergic receptor subtypes are involved in the calcium response. Given that SHRs are susceptible to cardiac arrhythmias, our data provide evidence for a potential link between arrhythmia and plasticity in calcium dynamics that occur not only in cardiomyocytes but also in the GP neurons of the heart.
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Affiliation(s)
- Joscelin E. G. Smith
- Department of Physiology, University of Auckland, Auckland, New Zealand
- Pūtahi Manawa, Centre for Heart Research, Auckland, New Zealand
| | - Jesse L. Ashton
- Department of Physiology, University of Auckland, Auckland, New Zealand
- Pūtahi Manawa, Centre for Heart Research, Auckland, New Zealand
| | - Liam P. Argent
- Department of Physiology, University of Auckland, Auckland, New Zealand
- Pūtahi Manawa, Centre for Heart Research, Auckland, New Zealand
| | | | - Johanna M. Montgomery
- Department of Physiology, University of Auckland, Auckland, New Zealand
- Pūtahi Manawa, Centre for Heart Research, Auckland, New Zealand
- *Correspondence: Johanna M. Montgomery,
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Hanna P, Dacey MJ, Brennan J, Moss A, Robbins S, Achanta S, Biscola NP, Swid MA, Rajendran PS, Mori S, Hadaya JE, Smith EH, Peirce SG, Chen J, Havton LA, Cheng Z(J, Vadigepalli R, Schwaber J, Lux RL, Efimov I, Tompkins JD, Hoover DB, Ardell JL, Shivkumar K. Innervation and Neuronal Control of the Mammalian Sinoatrial Node a Comprehensive Atlas. Circ Res 2021; 128:1279-1296. [PMID: 33629877 PMCID: PMC8284939 DOI: 10.1161/circresaha.120.318458] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
[Figure: see text].
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Affiliation(s)
- Peter Hanna
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, Department of Medicine
- UCLA Molecular, Cellular & Integrative Physiology Program, UCLA
| | - Michael J. Dacey
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, Department of Medicine
- UCLA Molecular, Cellular & Integrative Physiology Program, UCLA
| | - Jaclyn Brennan
- Bioengineering, George Washington University, Washington, DC
| | - Alison Moss
- Daniel Baugh Institute for Functional Genomics/Computational Biology, Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, PA
| | - Shaina Robbins
- Daniel Baugh Institute for Functional Genomics/Computational Biology, Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, PA
| | - Sirisha Achanta
- Daniel Baugh Institute for Functional Genomics/Computational Biology, Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, PA
| | | | - Mohammed A. Swid
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, Department of Medicine
| | - Pradeep S. Rajendran
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, Department of Medicine
| | - Shumpei Mori
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, Department of Medicine
| | - Joseph E. Hadaya
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, Department of Medicine
| | | | | | - Jin Chen
- University of Central Florida, Burnett School of Biomedical Sciences, College of Medicine, Orlando, FL
| | - Leif A. Havton
- Neurology, Icahn School of Medicine at Mount Sinai, New York City, NY
- Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY
- VA RR&D National Center of Excellence for the Medical Consequences of Spinal and; Cord Injury and Neurology Service, James J. Peters Veterans Administration Medical Center, Bronx, NY
| | - Zixi (Jack) Cheng
- University of Central Florida, Burnett School of Biomedical Sciences, College of Medicine, Orlando, FL
| | - Rajanikanth Vadigepalli
- Daniel Baugh Institute for Functional Genomics/Computational Biology, Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, PA
| | - James Schwaber
- Daniel Baugh Institute for Functional Genomics/Computational Biology, Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, PA
| | - Robert L. Lux
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, Department of Medicine
| | - Igor Efimov
- Bioengineering, George Washington University, Washington, DC
| | - John D. Tompkins
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, Department of Medicine
| | - Donald B. Hoover
- Biomedical Sciences
- Center of Excellence in Inflammation, Infectious Disease and Immunity, James H. Quillen College of Medicine, East Tennessee State University
| | - Jeffrey L. Ardell
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, Department of Medicine
- UCLA Molecular, Cellular & Integrative Physiology Program, UCLA
| | - Kalyanam Shivkumar
- University of California Los Angeles (UCLA) Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, Department of Medicine
- UCLA Molecular, Cellular & Integrative Physiology Program, UCLA
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7
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Halder N, Lal G. Cholinergic System and Its Therapeutic Importance in Inflammation and Autoimmunity. Front Immunol 2021; 12:660342. [PMID: 33936095 PMCID: PMC8082108 DOI: 10.3389/fimmu.2021.660342] [Citation(s) in RCA: 69] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 03/26/2021] [Indexed: 12/11/2022] Open
Abstract
Neurological and immunological signals constitute an extensive regulatory network in our body that maintains physiology and homeostasis. The cholinergic system plays a significant role in neuroimmune communication, transmitting information regarding the peripheral immune status to the central nervous system (CNS) and vice versa. The cholinergic system includes the neurotransmitter\ molecule, acetylcholine (ACh), cholinergic receptors (AChRs), choline acetyltransferase (ChAT) enzyme, and acetylcholinesterase (AChE) enzyme. These molecules are involved in regulating immune response and playing a crucial role in maintaining homeostasis. Most innate and adaptive immune cells respond to neuronal inputs by releasing or expressing these molecules on their surfaces. Dysregulation of this neuroimmune communication may lead to several inflammatory and autoimmune diseases. Several agonists, antagonists, and inhibitors have been developed to target the cholinergic system to control inflammation in different tissues. This review discusses how various molecules of the neuronal and non-neuronal cholinergic system (NNCS) interact with the immune cells. What are the agonists and antagonists that alter the cholinergic system, and how are these molecules modulate inflammation and immunity. Understanding the various functions of pharmacological molecules could help in designing better strategies to control inflammation and autoimmunity.
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Affiliation(s)
- Namrita Halder
- Laboratory of Autoimmunity and Tolerance, National Centre for Cell Science, Ganeshkhind, Pune, India
| | - Girdhari Lal
- Laboratory of Autoimmunity and Tolerance, National Centre for Cell Science, Ganeshkhind, Pune, India
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8
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Acharya S, Kundu D, Choi HJ, Kim KM. Metabotropic signaling cascade involved in α4β2 nicotinic acetylcholine receptor-mediated PKCβII activation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118721. [PMID: 32304729 DOI: 10.1016/j.bbamcr.2020.118721] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 04/04/2020] [Accepted: 04/10/2020] [Indexed: 01/27/2023]
Abstract
Nicotinic acetylcholine receptors (nAChRs) belong to the ionophore receptor family, which regulates plasma membrane conductance to Na+, K+, and Ca2+ ions. Some studies, however, have shown that nAChRs also employ second messengers for intracellular signaling. We previously showed that α4β2 nAChR mediates the translocation of protein kinase CβII (PKCβII) from the cytoplasm to the plasma membrane, which is a typical activation marker for PKCβII. In this study, we investigated the molecular mechanisms underlying PKCβII activation through α4β2 nAChR. α4β2 nAChR is the most abundant nAChR subtype and is implicated in various brain functions and diseases. Putative α4β2 nAChR signaling components were identified by knockdown or chemical inhibition of candidate proteins, and the signaling cascade was deduced by protein interactions in predicted cellular components. α4β2 nAChR-mediated PKCβII translocation was found to occur in an ionophore activity-independent manner. Nicotinic stimulation of α4β2 nAChR activated Src in a β-arrestin1 and 14-3-3η-dependent manner. Activated Src phosphorylated the tyrosine residue(s) on Syk molecules, which in turn interacted with phospholipase C γ1 to trigger the translocation of PKCβII to the cell membrane by elevating cellular diacylglycerol levels. The activated PKCβII in turn exerted a positive feedback effect on Src activation, suggesting that α4β2 nAChR signaling is amplified by a positive feedback loop. These findings provide novel information for unveiling the previously unclear metabotropic second messenger-based signal transduction pathway of nAChRs.
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Affiliation(s)
- Srijan Acharya
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju 61186, Republic of Korea
| | - Dooti Kundu
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju 61186, Republic of Korea
| | - Hyun Jin Choi
- College of Pharmacy, Cha University, Seongnam, Gyeonggi-do 13488, Republic of Korea
| | - Kyeong-Man Kim
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju 61186, Republic of Korea.
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9
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Aishah A, Hinton T, Waters KA, Machaalani R. The α3 and α4 nicotinic acetylcholine receptor (nAChR) subunits in the brainstem medulla of sudden infant death syndrome (SIDS). Neurobiol Dis 2019; 125:23-30. [PMID: 30665006 DOI: 10.1016/j.nbd.2019.01.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 01/15/2019] [Accepted: 01/16/2019] [Indexed: 12/17/2022] Open
Abstract
SIDS occurs in early infancy and predominantly during a sleep period. Abnormalities in nicotine receptor binding and in the expression of the nicotinic acetylcholine receptor (nAChR) subunits α7 and β2 have been reported in the brainstem of SIDS infants. This study focuses on the α3 and α4 nAChR subunits as α3 is important for early postnatal survival while α4 is crucial for nicotine-elicited antinociception and sleep-wake cycle regulation. Tissue from the rostral medulla of infants who died with a known cause of death (eSUDI, n = 7), and from SIDS classified as SIDS I (n = 8) and SIDS II (n = 27), was immunohistochemically stained for the α3 and α4 nAChR subunits and quantified in 9 nuclei comparing amongst these groups. The association with risk factors of sex, cigarette smoke exposure, upper respiratory tract infection (URTI), prone sleeping and bedsharing was also evaluated. Results showed that only α4 changes (increase) were evident in SIDS, occurring in the hypoglossal and cuneate nuclei of SIDS II infants and the nucleus of the spinal trigeminal tract of SIDS I infants. Amongst the SIDS infants, cigarette smoke exposure was only associated with decreased α4 in cribriform fibre tracts, while sex and bedsharing were associated with increases in α3 in the dorsal motor nucleus of the vagus and solitary nucleus, respectively. Combined, these findings suggest that abnormalities in endogenous acetylcholine synthesis and regulation may underlie the altered α3 and α4 nAChR subunit expressions in the SIDS brainstem medulla since the changes were not related to cigarette smoke exposure.
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Affiliation(s)
- Atqiya Aishah
- Discipline of Pharmacology, Faculty of Health and Medicine, The University of Sydney, NSW 2006, Australia; The Bosch Institute, Faculty of Health and Medicine, The University of Sydney, NSW 2006, Australia
| | - Tina Hinton
- Discipline of Pharmacology, Faculty of Health and Medicine, The University of Sydney, NSW 2006, Australia; The Bosch Institute, Faculty of Health and Medicine, The University of Sydney, NSW 2006, Australia
| | - Karen A Waters
- Central Clinical School of Medicine, Faculty of Health and Medicine, The University of Sydney, NSW 2006, Australia
| | - Rita Machaalani
- The Bosch Institute, Faculty of Health and Medicine, The University of Sydney, NSW 2006, Australia; Central Clinical School of Medicine, Faculty of Health and Medicine, The University of Sydney, NSW 2006, Australia.
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Bennett JA, Ture SK, Schmidt RA, Mastrangelo MA, Cameron SJ, Terry LE, Yule DI, Morrell CN, Lowenstein CJ. Acetylcholine Inhibits Platelet Activation. J Pharmacol Exp Ther 2019; 369:182-187. [PMID: 30765424 DOI: 10.1124/jpet.118.253583] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 02/12/2019] [Indexed: 12/18/2022] Open
Abstract
Platelets are key mediators of thrombosis. Many agonists of platelet activation are known, but fewer endogenous inhibitors of platelets, such as prostacyclin and nitric oxide (NO), have been identified. Acetylcholinesterase inhibitors, such as donepezil, can cause bleeding in patients, but the underlying mechanisms are not well understood. We hypothesized that acetylcholine is an endogenous inhibitor of platelets. We measured the effect of acetylcholine or analogs of acetylcholine on human platelet activation ex vivo. Acetylcholine and analogs of acetylcholine inhibited platelet activation, as measured by P-selectin translocation and glycoprotein IIb IIIa conformational changes. Conversely, we found that antagonists of the acetylcholine receptor, such as pancuronium, enhance platelet activation. Furthermore, drugs inhibiting acetylcholinesterase, such as donepezil, also inhibit platelet activation, suggesting that platelets release acetylcholine. We found that NO mediates acetylcholine inhibition of platelets. Our data suggest that acetylcholine is an endogenous inhibitor of platelet activation. The cholinergic system may be a novel target for antithrombotic therapies.
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Affiliation(s)
- John A Bennett
- Aab Cardiovascular Research Institute, Department of Medicine (J.A.B., S.K.T., R.A.S., M.A.M., S.J.C., C.N.M., C.J.L.) and Department of Pharmacology and Physiology (L.E.T., D.I.Y.), University of Rochester Medical Center, Rochester, New York
| | - Sara K Ture
- Aab Cardiovascular Research Institute, Department of Medicine (J.A.B., S.K.T., R.A.S., M.A.M., S.J.C., C.N.M., C.J.L.) and Department of Pharmacology and Physiology (L.E.T., D.I.Y.), University of Rochester Medical Center, Rochester, New York
| | - Rachel A Schmidt
- Aab Cardiovascular Research Institute, Department of Medicine (J.A.B., S.K.T., R.A.S., M.A.M., S.J.C., C.N.M., C.J.L.) and Department of Pharmacology and Physiology (L.E.T., D.I.Y.), University of Rochester Medical Center, Rochester, New York
| | - Michael A Mastrangelo
- Aab Cardiovascular Research Institute, Department of Medicine (J.A.B., S.K.T., R.A.S., M.A.M., S.J.C., C.N.M., C.J.L.) and Department of Pharmacology and Physiology (L.E.T., D.I.Y.), University of Rochester Medical Center, Rochester, New York
| | - Scott J Cameron
- Aab Cardiovascular Research Institute, Department of Medicine (J.A.B., S.K.T., R.A.S., M.A.M., S.J.C., C.N.M., C.J.L.) and Department of Pharmacology and Physiology (L.E.T., D.I.Y.), University of Rochester Medical Center, Rochester, New York
| | - Lara E Terry
- Aab Cardiovascular Research Institute, Department of Medicine (J.A.B., S.K.T., R.A.S., M.A.M., S.J.C., C.N.M., C.J.L.) and Department of Pharmacology and Physiology (L.E.T., D.I.Y.), University of Rochester Medical Center, Rochester, New York
| | - David I Yule
- Aab Cardiovascular Research Institute, Department of Medicine (J.A.B., S.K.T., R.A.S., M.A.M., S.J.C., C.N.M., C.J.L.) and Department of Pharmacology and Physiology (L.E.T., D.I.Y.), University of Rochester Medical Center, Rochester, New York
| | - Craig N Morrell
- Aab Cardiovascular Research Institute, Department of Medicine (J.A.B., S.K.T., R.A.S., M.A.M., S.J.C., C.N.M., C.J.L.) and Department of Pharmacology and Physiology (L.E.T., D.I.Y.), University of Rochester Medical Center, Rochester, New York
| | - Charles J Lowenstein
- Aab Cardiovascular Research Institute, Department of Medicine (J.A.B., S.K.T., R.A.S., M.A.M., S.J.C., C.N.M., C.J.L.) and Department of Pharmacology and Physiology (L.E.T., D.I.Y.), University of Rochester Medical Center, Rochester, New York
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11
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Deng Y, Tan X, Li ML, Wang WZ, Wang YK. Angiotensin-Converting Enzyme 2 in the Rostral Ventrolateral Medulla Regulates Cholinergic Signaling and Cardiovascular and Sympathetic Responses in Hypertensive Rats. Neurosci Bull 2019; 35:67-78. [PMID: 30318562 PMCID: PMC6357273 DOI: 10.1007/s12264-018-0298-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 08/07/2018] [Indexed: 02/07/2023] Open
Abstract
The rostral ventrolateral medulla (RVLM) is a key region in cardiovascular regulation. It has been demonstrated that cholinergic synaptic transmission in the RVLM is enhanced in hypertensive rats. Angiotensin-converting enzyme 2 (ACE2) in the brain plays beneficial roles in cardiovascular function in hypertension. The purpose of this study was to determine the effect of ACE2 overexpression in the RVLM on cholinergic synaptic transmission in spontaneously hypertensive rats (SHRs). Four weeks after injecting lentiviral particles containing enhanced green fluorescent protein and ACE2 bilaterally into the RVLM, the blood pressure and heart rate were notably decreased. ACE2 overexpression significantly reduced the concentration of acetylcholine in microdialysis fluid from the RVLM and blunted the decrease in blood pressure evoked by bilateral injection of atropine into the RVLM in SHRs. In conclusion, we suggest that ACE2 overexpression in the RVLM attenuates the enhanced cholinergic synaptic transmission in SHRs.
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Affiliation(s)
- Yu Deng
- Department of Physiology, Second Military Medical University, Shanghai, 200433, China
- Department of Anesthesiology, Changhai Hospital, Shanghai, 200433, China
| | - Xing Tan
- Department of Physiology, Second Military Medical University, Shanghai, 200433, China
- Institution of Polar Medicine Research Center, Second Military Medical University, Shanghai, 200433, China
| | - Miao-Ling Li
- Institute of Cardiovascular Medical Research, Southwest Medical University, Luzhou, 646000, China
| | - Wei-Zhong Wang
- Department of Physiology, Second Military Medical University, Shanghai, 200433, China
- Institution of Polar Medicine Research Center, Second Military Medical University, Shanghai, 200433, China
| | - Yang-Kai Wang
- Department of Physiology, Second Military Medical University, Shanghai, 200433, China.
- Institution of Polar Medicine Research Center, Second Military Medical University, Shanghai, 200433, China.
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12
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Zhao Y, Wang Z, Lao W, Kuang P, Jiang N, Yin T, Lin W, Zhu H, Ji Y. Anticonvulsant effect of gentamicin on the seizures induced by kainic acid. Neurol Res 2017; 40:45-52. [DOI: 10.1080/01616412.2017.1390932] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Yuxiao Zhao
- School of Life Science, Shanghai University, Shanghai, China
| | - Ziyi Wang
- School of Life Science, Shanghai University, Shanghai, China
| | - Wenwen Lao
- School of Life Science, Shanghai University, Shanghai, China
| | - Ping Kuang
- School of Life Science, Shanghai University, Shanghai, China
| | - Nan Jiang
- School of Life Science, Shanghai University, Shanghai, China
| | - Tao Yin
- School of Life Science, Shanghai University, Shanghai, China
| | - Weide Lin
- School of Life Science, Shanghai University, Shanghai, China
| | - Hongyan Zhu
- School of Life Science, Shanghai University, Shanghai, China
| | - Yonghua Ji
- School of Life Science, Shanghai University, Shanghai, China
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13
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Fisher AG, Seaborne RA, Hughes TM, Gutteridge A, Stewart C, Coulson JM, Sharples AP, Jarvis JC. Transcriptomic and epigenetic regulation of disuse atrophy and the return to activity in skeletal muscle. FASEB J 2017; 31:5268-5282. [DOI: 10.1096/fj.201700089rr] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 07/25/2017] [Indexed: 01/09/2023]
Affiliation(s)
- Andrew G. Fisher
- Institute for Ageing and Chronic DiseaseUniversity of Liverpool Liverpool United Kingdom
| | - Robert A. Seaborne
- Institute for Science and Technology in MedicineKeele University Medical SchoolKeele University Staffordshire United Kingdom
- Stem Cells, Ageing, and Molecular Physiology Research UnitExercise Metabolism and Adaptation Research GroupResearch Institute for Sport and Exercise SciencesLiverpool John Moores University Liverpool United Kingdom
| | - Thomas M. Hughes
- Instituto de Física y AstronomíaUniversidad de Valparaíso Valparaíso Chile
| | | | - Claire Stewart
- Institute for Science and Technology in MedicineKeele University Medical SchoolKeele University Staffordshire United Kingdom
| | - Judy M. Coulson
- Department of Cellular and Molecular PhysiologyInstitute of Translational MedicineUniversity of Liverpool Liverpool United Kingdom
| | - Adam P. Sharples
- Institute for Science and Technology in MedicineKeele University Medical SchoolKeele University Staffordshire United Kingdom
- Stem Cells, Ageing, and Molecular Physiology Research UnitExercise Metabolism and Adaptation Research GroupResearch Institute for Sport and Exercise SciencesLiverpool John Moores University Liverpool United Kingdom
| | - Jonathan C. Jarvis
- Stem Cells, Ageing, and Molecular Physiology Research UnitExercise Metabolism and Adaptation Research GroupResearch Institute for Sport and Exercise SciencesLiverpool John Moores University Liverpool United Kingdom
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14
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Ghasemi M, Hadipour-Niktarash A. Pathologic role of neuronal nicotinic acetylcholine receptors in epileptic disorders: implication for pharmacological interventions. Rev Neurosci 2016; 26:199-223. [PMID: 25565544 DOI: 10.1515/revneuro-2014-0044] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2014] [Accepted: 10/16/2014] [Indexed: 12/30/2022]
Abstract
Accumulating evidence suggests that neuronal nicotinic acetylcholine receptors (nAChRs) may play a key role in the pathophysiology of some neurological diseases such as epilepsy. Based on genetic studies in patients with epileptic disorders worldwide and animal models of seizure, it has been demonstrated that nAChR activity is altered in some specific types of epilepsy, including autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) and juvenile myoclonic epilepsy (JME). Neuronal nAChR antagonists also have antiepileptic effects in pre-clinical studies. There is some evidence that conventional antiepileptic drugs may affect neuronal nAChR function. In this review, we re-examine the evidence for the involvement of nAChRs in the pathophysiology of some epileptic disorders, especially ADNFLE and JME, and provide an overview of nAChR antagonists that have been evaluated in animal models of seizure.
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Beaumont E, Wright GL, Southerland EM, Li Y, Chui R, KenKnight BH, Armour JA, Ardell JL. Vagus nerve stimulation mitigates intrinsic cardiac neuronal remodeling and cardiac hypertrophy induced by chronic pressure overload in guinea pig. Am J Physiol Heart Circ Physiol 2016; 310:H1349-59. [PMID: 26993230 DOI: 10.1152/ajpheart.00939.2015] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 03/17/2016] [Indexed: 02/06/2023]
Abstract
Our objective was to determine whether chronic vagus nerve stimulation (VNS) mitigates pressure overload (PO)-induced remodeling of the cardioneural interface. Guinea pigs (n = 48) were randomized to right or left cervical vagus (RCV or LCV) implant. After 2 wk, chronic left ventricular PO was induced by partial (15-20%) aortic constriction. Of the 31 animals surviving PO induction, 10 were randomized to RCV VNS, 9 to LCV VNS, and 12 to sham VNS. VNS was delivered at 20 Hz and 1.14 ± 0.03 mA at a 22% duty cycle. VNS commenced 10 days after PO induction and was maintained for 40 days. Time-matched controls (n = 9) were evaluated concurrently. Echocardiograms were obtained before and 50 days after PO. At termination, intracellular current-clamp recordings of intrinsic cardiac (IC) neurons were studied in vitro to determine effects of therapy on soma characteristics. Ventricular cardiomyocyte sizes were assessed with histology along with immunoblot analysis of selected proteins in myocardial tissue extracts. In sham-treated animals, PO increased cardiac output (34%, P < 0.004), as well as systolic (114%, P < 0.04) and diastolic (49%, P < 0.002) left ventricular volumes, a hemodynamic response prevented by VNS. PO-induced enhancements of IC synaptic efficacy and muscarinic sensitivity of IC neurons were mitigated by chronic VNS. Increased myocyte size, which doubled in PO (P < 0.05), was mitigated by RCV. PO hypertrophic myocardium displayed decreased glycogen synthase (GS) protein levels and accumulation of the phosphorylated (inactive) form of GS. These PO-induced changes in GS were moderated by left VNS. Chronic VNS targets IC neurons accompanying PO to obtund associated adverse cardiomyocyte remodeling.
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Affiliation(s)
- Eric Beaumont
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee
| | - Gary L Wright
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee
| | - Elizabeth M Southerland
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee
| | - Ying Li
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee
| | - Ray Chui
- Molecular, Cellular, and Integrative Physiology Program, University of California, Los Angeles, California
| | | | - J Andrew Armour
- UCLA Neurocardiology Research Center of Excellence and UCLA Cardiac Arrhythmia Center, Los Angeles, California
| | - Jeffrey L Ardell
- Molecular, Cellular, and Integrative Physiology Program, University of California, Los Angeles, California; UCLA Neurocardiology Research Center of Excellence and UCLA Cardiac Arrhythmia Center, Los Angeles, California
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16
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Kalla M, Chotalia M, Coughlan C, Hao G, Crabtree MJ, Tomek J, Bub G, Paterson DJ, Herring N. Protection against ventricular fibrillation via cholinergic receptor stimulation and the generation of nitric oxide. J Physiol 2016; 594:3981-92. [PMID: 26752781 PMCID: PMC4794549 DOI: 10.1113/jp271588] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 01/06/2016] [Indexed: 12/12/2022] Open
Abstract
KEY POINTS Animal studies suggest an anti-fibrillatory action of the vagus nerve on the ventricle, although the exact mechanism is controversial. Using a Langendorff perfused rat heart, we show that the acetylcholine analogue carbamylcholine raises ventricular fibrillation threshold (VFT) and flattens the electrical restitution curve. The anti-fibrillatory action of carbamylcholine was prevented by the nicotinic receptor antagonist mecamylamine, inhibitors of neuronal nitric oxide synthase (nNOS) and soluble guanylyl cyclase (sGC), and can be mimicked by the nitric oxide (NO) donor sodium nitroprusside. Carbamylcholine increased NO metabolite content in the coronary effluent and this was prevented by mecamylamine. The anti-fibrillatory action of both carbamylcholine and sodium nitroprusside was ultimately dependent on muscarinic receptor stimulation as all effects were blocked by atropine. These data demonstrate a protective effect of carbamylcholine on VFT that depends upon both muscarinic and nicotinic receptor stimulation, where the generation of NO is likely to be via a neuronal nNOS-sGC dependent pathway. ABSTRACT Implantable cardiac vagal nerve stimulators are a promising treatment for ventricular arrhythmia in patients with heart failure. Animal studies suggest the anti-fibrillatory effect may be nitric oxide (NO) dependent, although the exact site of action is controversial. We investigated whether a stable analogue of acetylcholine could raise ventricular fibrillation threshold (VFT), and whether this was dependent on NO generation and/or muscarinic/nicotinic receptor stimulation. VFT was determined in Langendorff perfused rat hearts by burst pacing until sustained VF was induced. Carbamylcholine (CCh, 200 nmol l(-1) , n = 9) significantly (P < 0.05) reduced heart rate from 292 ± 8 to 224 ± 6 b.p.m. Independent of this heart rate change, CCh caused a significant increase in VFT (control 1.5 ± 0.3 mA, CCh 2.4 ± 0.4 mA, wash 1.1 ± 0.2 mA) and flattened the restitution curve (n = 6) derived from optically mapped action potentials. The effect of CCh on VFT was abolished by a muscarinic (atropine, 0.1 μmol l(-1) , n = 6) or a nicotinic receptor antagonist (mecamylamine, 10 μmol l(-1) , n = 6). CCh significantly increased NOx content in coronary effluent (n = 8), but not in the presence of mecamylamine (n = 8). The neuronal nitric oxide synthase inhibitor AAAN (N-(4S)-4-amino-5-[aminoethyl]aminopentyl-N'-nitroguanidine; 10 μmol l(-1) , n = 6) or soluble guanylate cyclase (sGC) inhibitor ODQ (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one; 10 μmol l(-1) , n = 6) prevented the rise in VFT with CCh. The NO donor sodium nitrprusside (10 μmol l(-1) , n = 8) mimicked the action of CCh on VFT, an effect that was also blocked by atropine (n = 10). These data demonstrate a protective effect of CCh on VFT that depends upon both muscarinic and nicotinic receptor stimulation, where the generation of NO is likely to be via a neuronal nNOS/sGC-dependent pathway.
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Affiliation(s)
- Manish Kalla
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Oxford, UK
| | - Minesh Chotalia
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Oxford, UK
| | - Charles Coughlan
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Oxford, UK
| | - Guoliang Hao
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Oxford, UK
| | - Mark J Crabtree
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Oxford, UK
| | - Jakub Tomek
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Oxford, UK
| | - Gil Bub
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Oxford, UK
| | - David J Paterson
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Oxford, UK
| | - Neil Herring
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Oxford, UK
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17
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Muscarinic receptor-mediated excitation of rat intracardiac ganglion neurons. Neuropharmacology 2015; 95:395-404. [DOI: 10.1016/j.neuropharm.2015.04.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 03/13/2015] [Accepted: 04/14/2015] [Indexed: 11/23/2022]
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18
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Hill M, Dušková M, Stárka L. Dehydroepiandrosterone, its metabolites and ion channels. J Steroid Biochem Mol Biol 2015; 145:293-314. [PMID: 24846830 DOI: 10.1016/j.jsbmb.2014.05.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Revised: 05/06/2014] [Accepted: 05/11/2014] [Indexed: 11/20/2022]
Abstract
This review is focused on the physiological and pathophysiological relevance of steroids influencing the activities of the central and peripheral nervous systems with regard to their concentrations in body fluids and tissues in various stages of human life like the fetal development or pregnancy. The data summarized in this review shows that DHEA and its unconjugated and sulfated metabolites are physiologically and pathophysiologically relevant in modulating numerous ion channels and participate in vital functions of the human organism. DHEA and its unconjugated and sulfated metabolites including 5α/β-reduced androstane steroids participate in various physiological and pathophysiological processes like the management of GnRH cyclic release, regulation of glandular and neurotransmitter secretions, maintenance of glucose homeostasis on one hand and insulin insensitivity on the other hand, control of skeletal muscle and smooth muscle activities including vasoregulation, promotion of tolerance to ischemia and other neuroprotective effects. In respect of prevalence of steroid sulfates over unconjugated steroids in the periphery and the opposite situation in the CNS, the sulfated androgens and androgen metabolites reach relevance in peripheral organs. The unconjugated androgens and estrogens are relevant in periphery and so much the more in the CNS due to higher concentrations of most unconjugated steroids in the CNS tissues than in circulation and peripheral organs. This article is part of a Special Issue entitled "Essential role of DHEA".
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Affiliation(s)
- M Hill
- Steroid Hormone Unit, Institute of Endocrinology, Národní třída 8, Prague 116 94, Praha 1, CZ 116 94, Czech Republic.
| | - M Dušková
- Steroid Hormone Unit, Institute of Endocrinology, Národní třída 8, Prague 116 94, Praha 1, CZ 116 94, Czech Republic.
| | - L Stárka
- Steroid Hormone Unit, Institute of Endocrinology, Národní třída 8, Prague 116 94, Praha 1, CZ 116 94, Czech Republic.
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Kann O, Taubenberger N, Huchzermeyer C, Papageorgiou IE, Benninger F, Heinemann U, Kovács R. Muscarinic receptor activation determines the effects of store-operated Ca2+-entry on excitability and energy metabolism in pyramidal neurons. Cell Calcium 2012; 51:40-50. [DOI: 10.1016/j.ceca.2011.10.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 10/14/2011] [Accepted: 10/19/2011] [Indexed: 10/15/2022]
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20
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Girasole AE, Palmer CP, Corrado SL, Marie Southerland E, Ardell JL, Hardwick JC. Angiotensin II potentiates adrenergic and muscarinic modulation of guinea pig intracardiac neurons. Am J Physiol Regul Integr Comp Physiol 2011; 301:R1391-9. [PMID: 21865545 DOI: 10.1152/ajpregu.00145.2011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The intrinsic cardiac plexus represents a major peripheral integration site for neuronal, hormonal, and locally produced neuromodulators controlling efferent neuronal output to the heart. This study examined the interdependence of norepinephrine, muscarinic agonists, and ANG II, to modulate intrinsic cardiac neuronal activity. Intracellular voltage recordings from whole-mount preparations of the guinea pig cardiac plexus were used to determine changes in active and passive electrical properties of individual intrinsic cardiac neurons. Application of either adrenergic or muscarinic agonists induced changes in neuronal resting membrane potentials, decreased afterhyperpolarization duration of single action potentials, and increased neuronal excitability. Adrenergic responses were inhibited by removal of extracellular calcium ions, while muscarinic responses were inhibited by application of TEA. The adrenergic responses were heterogeneous, responding to a variety of receptor-specific agonists (phenylephrine, clonidine, dobutamine, and terbutaline), although α-receptor agonists produced the most frequent responses. Application of ANG II alone produced a significant increase in excitability, while application of ANG II in combination with either adrenergic or muscarinic agonists produced a much larger potentiation of excitability. The ANG II-induced modulation of firing was blocked by the angiotensin type 2 (AT(2)) receptor inhibitor PD 123319 and was mimicked by the AT(2) receptor agonist CGP-42112A. AT(1) receptor blockade with telmasartin did not alter neuronal responses to ANG II. These data demonstrate that ANG II potentiates both muscarinically and adrenergically mediated activation of intrinsic cardiac neurons, doing so primarily via AT(2) receptor-dependent mechanisms. These neurohumoral interactions may be fundamental to regulation of neuronal excitability within the intrinsic cardiac nervous system.
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21
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Dyavanapalli J, Rimmer K, Harper AA. Reactive oxygen species alters the electrophysiological properties and raises [Ca2+]i in intracardiac ganglion neurons. Am J Physiol Regul Integr Comp Physiol 2010; 299:R42-54. [PMID: 20445155 PMCID: PMC2917765 DOI: 10.1152/ajpregu.00053.2010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have investigated the effects of the reactive oxygen species (ROS) donors hydrogen peroxide (H2O2) and tert-butyl hydroperoxide (t-BHP) on the intrinsic electrophysiological characteristics: ganglionic transmission and resting [Ca2+]i in neonate and adult rat intracardiac ganglion (ICG) neurons. Intracellular recordings were made using sharp microelectrodes filled with either 0.5 M KCl or Oregon Green 488 BAPTA-1, allowing recording of electrical properties and measurement of [Ca2+]i. H2O2 and t-BHP both hyperpolarized the resting membrane potential and reduced membrane resistance. In adult ICG neurons, the hyperpolarizing action of H2O2 was reversed fully by Ba2+ and partially by tetraethylammonium, muscarine, and linopirdine. H2O2 and t-BHP reduced the action potential afterhyperpolarization (AHP) amplitude but had no impact on either overshoot or AHP duration. ROS donors evoked an increase in discharge adaptation to long depolarizing current pulses. H2O2 blocked ganglionic transmission in most ICG neurons but did not alter nicotine-evoked depolarizations. By contrast, t-BHP had no significant action on ganglionic transmission. H2O2 and t-BHP increased resting intracellular Ca2+ levels to 1.6 ( ± 0.6, n = 11, P < 0.01) and 1.6 ( ± 0.3, n = 8, P < 0.001), respectively, of control value (1.0, ∼60 nM). The ROS scavenger catalase prevented the actions of H2O2, and this protection extended beyond the period of application. Superoxide dismutase partially shielded against the action of H2O2, but this was limited to the period of application. These data demonstrate that ROS decreases the excitability and ganglionic transmission of ICG neurons, attenuating parasympathetic control of the heart.
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Affiliation(s)
- Jhansi Dyavanapalli
- Division of Molecular Physiology, James Black Centre, College of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom
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22
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Cholinergic signal transduction in the mouse sphenopalatine ganglion. Brain Res 2008; 1241:42-55. [PMID: 18817758 DOI: 10.1016/j.brainres.2008.08.095] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Revised: 08/28/2008] [Accepted: 08/28/2008] [Indexed: 01/27/2023]
Abstract
The sphenopalatine ganglia (SPG) receive their preganglionic innervation from the ventro-lateral reticular formation and nuclei of the caudal pons, and are involved in parasympathetic control of cranial glandular and vascular components including the blood supply to specific brain areas. In 53% of all SPG neurons, a particular member (MOL2.3) of the odorant receptor superfamily is co-expressed with green fluorescent protein (GFP) in MOL2.3 transgenic mouse pups. Choline acetyltransferase and vesicular acetylcholine transporter (VAChT) could be demonstrated in 90% of the GFP-positive, and 60% of the GFP-negative cells, these cells thus representing cholinergic neurons. Some 50% of all SPG neurons were nitrergic at a high rate of VAChT co-expression, the majority of them being GFP-positive. Most SPG neurons received cholinergic innervation as demonstrated by perineuronal VAChT immunoreactive nerve terminals. To characterize cholinergic signal transduction in SPG neurons, calcium imaging experiments were performed in a SPG primary culture system containing GFP-positive and -negative neurons. Ganglionic neurons could repeatedly be activated by cholinergic stimulation in a dose-dependent manner, with calcium entering all cells from the extracellular compartment. Stimulation with specific agonists supported prevalence of nicotinic cholinergic receptors (nAChRs). Inhibition of cholinergically induced intracellular calcium signalling by various omega-conotoxins indicated functional expression of alpha 3 beta 4 and alpha 7 nAChR subtypes in murine SPG cells, which could be supported by RT-PCR analysis of the neonatal mouse SPG. With regard to secondary cholinergic activation, L- but not N-subtype voltage-gated calcium channels might represent a prime target. Nicotinic signal transduction did not prove to be different in GFP-positive as compared to-negative murine SPG neurons.
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23
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Kalamida D, Poulas K, Avramopoulou V, Fostieri E, Lagoumintzis G, Lazaridis K, Sideri A, Zouridakis M, Tzartos SJ. Muscle and neuronal nicotinic acetylcholine receptors. FEBS J 2007; 274:3799-845. [PMID: 17651090 DOI: 10.1111/j.1742-4658.2007.05935.x] [Citation(s) in RCA: 216] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Nicotinic acetylcholine receptors (nAChRs) are integral membrane proteins and prototypic members of the ligand-gated ion-channel superfamily, which has precursors in the prokaryotic world. They are formed by the assembly of five transmembrane subunits, selected from a pool of 17 homologous polypeptides (alpha1-10, beta1-4, gamma, delta, and epsilon). There are many nAChR subtypes, each consisting of a specific combination of subunits, which mediate diverse physiological functions. They are widely expressed in the central nervous system, while, in the periphery, they mediate synaptic transmission at the neuromuscular junction and ganglia. nAChRs are also found in non-neuronal/nonmuscle cells (keratinocytes, epithelia, macrophages, etc.). Extensive research has determined the specific function of several nAChR subtypes. nAChRs are now important therapeutic targets for various diseases, including myasthenia gravis, Alzheimer's and Parkinson's diseases, and schizophrenia, as well as for the cessation of smoking. However, knowledge is still incomplete, largely because of a lack of high-resolution X-ray structures for these molecules. Nevertheless, electron microscopy studies on 2D crystals of nAChR from fish electric organs and the determination of the high-resolution X-ray structure of the acetylcholine binding protein (AChBP) from snails, a homolog of the extracellular domain of the nAChR, have been major steps forward and the data obtained have important implications for the design of subtype-specific drugs. Here, we review some of the latest advances in our understanding of nAChRs and their involvement in physiology and pathology.
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Affiliation(s)
- Dimitra Kalamida
- Department of Pharmacy, University of Patras, Rio Patras, Greece
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24
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Tompkins JD, Ardell JL, Hoover DB, Parsons RL. Neurally released pituitary adenylate cyclase-activating polypeptide enhances guinea pig intrinsic cardiac neurone excitability. J Physiol 2007; 582:87-93. [PMID: 17495034 PMCID: PMC2075297 DOI: 10.1113/jphysiol.2007.134965] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Intracellular recordings were made in vitro from guinea-pig cardiac ganglia to determine whether endogenous neuropeptides such as pituitary adenylate cyclase-activating polypeptide (PACAP) or substance P released during tetanic neural stimulation modulate cardiac neurone excitability and/or contribute to slow excitatory postsynaptic potentials (sEPSPs). When nicotinic and muscarinic receptors were blocked by hexamethonium and atropine, 20 Hz stimulation for 10 s initiated a sEPSP in all innervated neurones. In 40% of the cells, excitability was enhanced after termination of the sEPSP. This suggested that non-cholinergic receptor-mediated mechanisms contributed to the sEPSP and modulated neuronal excitability. Exogenous PACAP and substance P initiated a slow depolarization in the neurones whereas neuronal excitability was only increased by PACAP. When ganglia were treated with the PAC1 antagonist PACAP6-38 (500 nM), the sEPSP evoked by 20 Hz stimulation was reduced by approximately 50% and an enhanced excitability occurred in only 10% of the cells. These observations suggested that PACAP released from preganglionic nerve terminals during tetanic stimulation enhanced neuronal excitability and evoked sEPSPs. After addition of 1 nM PACAP to the bath, 7 of 9 neurones exhibited a tonic firing pattern whereas in untreated preparations, the neurons had a phasic firing pattern. PACAP6-38 (500 nM) diminished the increase in excitability caused by 1 nM PACAP so that only 4 of 13 neurones exhibited a tonic firing pattern and the other 9 cells retained a phasic firing pattern. These findings indicate that PACAP can be released by tetanic neural stimulation in vitro and increase the excitability of intrinsic cardiac neurones. We hypothesize that in vivo PACAP released during preganglionic firing may modulate neurotransmission within the intrinsic cardiac ganglia.
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MESH Headings
- Animals
- Atropine/pharmacology
- Autonomic Fibers, Preganglionic/metabolism
- Electric Stimulation/methods
- Excitatory Postsynaptic Potentials
- Ganglia, Parasympathetic/cytology
- Ganglia, Parasympathetic/drug effects
- Ganglia, Parasympathetic/metabolism
- Guinea Pigs
- Heart/innervation
- Heart Atria/innervation
- Hexamethonium/pharmacology
- In Vitro Techniques
- Kinetics
- Muscarinic Antagonists/pharmacology
- Neurons/drug effects
- Neurons/metabolism
- Nicotinic Antagonists/pharmacology
- Peptide Fragments/pharmacology
- Pituitary Adenylate Cyclase-Activating Polypeptide/metabolism
- Pituitary Adenylate Cyclase-Activating Polypeptide/pharmacology
- Receptors, Muscarinic/drug effects
- Receptors, Nicotinic/drug effects
- Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I/antagonists & inhibitors
- Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I/metabolism
- Substance P/pharmacology
- Synaptic Transmission/drug effects
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Affiliation(s)
- John D Tompkins
- Department of Anatomy and Neurobiology, College of Medicine, University of Vermont, Burlington, VT 05405, USA
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25
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Welsby P, Rowan M, Anwyl R. Nicotinic receptor-mediated enhancement of long-term potentiation involves activation of metabotropic glutamate receptors and ryanodine-sensitive calcium stores in the dentate gyrus. Eur J Neurosci 2006; 24:3109-18. [PMID: 17156372 DOI: 10.1111/j.1460-9568.2006.05187.x] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Little is known about the mechanisms underlying the enhancement of long-term potentiation (LTP) by nicotine. In the present study, the mechanisms of nicotinic enhancement of LTP were investigated in the rat dentate gyrus in vitro. Acute application of nicotine enhanced LTP induction, an action requiring activation of alpha7 nicotinic acetylcholine receptors (nAChRs), as it was blocked by the nAChR antagonist methyl-lycaconitine, mimicked by the acetylcholine receptor agonist choline and absent in mutant mice null for alpha7 nAChR. Nicotinic enhancement of LTP was both dependent on N-methyl-D-aspartate receptor activation, as no LTP was induced in the presence of nicotine and an N-methyl-D-aspartate receptor antagonist, and expressed post-synaptically, as no change in paired-pulse ratio accompanied nicotinic enhancement of LTP. The nicotinic-enhanced component of LTP, unlike control LTP, was dependent on activation of metabotropic glutamate receptors (mGluRs), being inhibited by the group I/II antagonist LY341495 and the mGluR5 antagonist MPEP, and also dependent on influx of Ca via L-type Ca channels and release from ryanodine (RyR)-sensitive intracellular stores, being prevented by nifedipine and RyR, respectively. It is suggested that nicotinic activation of the Ca-permeable alpha7 nAChRs fills RyR Ca stores and release of Ca from such stores by high-frequency stimulation via Ca-induced Ca release and activation of mGluRs induces an additional component of LTP which summates with control LTP. Chronic application of nicotine in vivo also enhanced LTP induction in slices and was dependent on activation of mGluRs and Ca release from RyR-sensitive intracellular stores, although acutely applied nicotine was not required for such enhanced LTP.
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MESH Headings
- Animals
- Calcium Channel Blockers/pharmacology
- Calcium Channels, L-Type/drug effects
- Calcium Channels, L-Type/metabolism
- Calcium Signaling/drug effects
- Calcium Signaling/physiology
- Dentate Gyrus/drug effects
- Dentate Gyrus/metabolism
- Excitatory Amino Acid Antagonists/pharmacology
- Long-Term Potentiation/drug effects
- Long-Term Potentiation/physiology
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Neural Pathways/drug effects
- Neural Pathways/metabolism
- Neuronal Plasticity/drug effects
- Neuronal Plasticity/physiology
- Neurons/drug effects
- Neurons/metabolism
- Nicotinic Agonists/pharmacology
- Nicotinic Antagonists/pharmacology
- Organ Culture Techniques
- Rats
- Rats, Wistar
- Receptors, Metabotropic Glutamate/drug effects
- Receptors, Metabotropic Glutamate/metabolism
- Receptors, N-Methyl-D-Aspartate/drug effects
- Receptors, N-Methyl-D-Aspartate/metabolism
- Receptors, Nicotinic/drug effects
- Receptors, Nicotinic/genetics
- Receptors, Nicotinic/metabolism
- Ryanodine Receptor Calcium Release Channel/drug effects
- Ryanodine Receptor Calcium Release Channel/metabolism
- Synaptic Transmission/drug effects
- Synaptic Transmission/physiology
- alpha7 Nicotinic Acetylcholine Receptor
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Affiliation(s)
- Philip Welsby
- Department of Physiology, Trinity College, Dublin 2, Ireland
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Weber M, Motin L, Gaul S, Beker F, Fink RHA, Adams DJ. Intravenous anaesthetics inhibit nicotinic acetylcholine receptor-mediated currents and Ca2+ transients in rat intracardiac ganglion neurons. Br J Pharmacol 2005; 144:98-107. [PMID: 15644873 PMCID: PMC1575970 DOI: 10.1038/sj.bjp.0705942] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The effects of intravenous (i.v.) anaesthetics on nicotinic acetylcholine receptor (nAChR)-induced transients in intracellular free Ca(2+) concentration ([Ca(2+)](i)) and membrane currents were investigated in neonatal rat intracardiac neurons. In fura-2-loaded neurons, nAChR activation evoked a transient increase in [Ca(2+)](I), which was inhibited reversibly and selectively by clinically relevant concentrations of thiopental. The half-maximal concentration for thiopental inhibition of nAChR-induced [Ca(2+)](i) transients was 28 microM, close to the estimated clinical EC(50) (clinically relevant (half-maximal) effective concentration) of thiopental. In fura-2-loaded neurons, voltage clamped at -60 mV to eliminate any contribution of voltage-gated Ca(2+) channels, thiopental (25 microM) simultaneously inhibited nAChR-induced increases in [Ca(2+)](i) and peak current amplitudes. Thiopental inhibited nAChR-induced peak current amplitudes in dialysed whole-cell recordings by approximately 40% at -120, -80 and -40 mV holding potential, indicating that the inhibition is voltage independent. The barbiturate, pentobarbital and the dissociative anaesthetic, ketamine, used at clinical EC(50) were also shown to inhibit nAChR-induced increases in [Ca(2+)](i) by approximately 40%. Thiopental (25 muM) did not inhibit caffeine-, muscarine- or ATP-evoked increases in [Ca(2+)](i), indicating that inhibition of Ca(2+) release from internal stores via either ryanodine receptor or inositol-1,4,5-trisphosphate receptor channels is unlikely. Depolarization-activated Ca(2+) channel currents were unaffected in the presence of thiopental (25 microM), pentobarbital (50 microM) and ketamine (10 microM). In conclusion, i.v. anaesthetics inhibit nAChR-induced currents and [Ca(2+)](i) transients in intracardiac neurons by binding to nAChRs and thereby may contribute to changes in heart rate and cardiac output under clinical conditions.
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MESH Headings
- Acetylcholine/pharmacology
- Anesthetics, Dissociative/pharmacology
- Anesthetics, Intravenous/pharmacology
- Animals
- Animals, Newborn
- Barbiturates/pharmacology
- Calcium/metabolism
- Cells, Cultured
- Electric Conductivity
- Fluorescent Dyes
- Fura-2
- Ganglia, Parasympathetic/cytology
- Ganglia, Parasympathetic/metabolism
- Ganglia, Parasympathetic/physiology
- Heart/innervation
- Ketamine/pharmacology
- Neurons/drug effects
- Neurons/metabolism
- Neurons/physiology
- Patch-Clamp Techniques
- Pentobarbital/pharmacology
- Rats
- Rats, Wistar
- Receptors, Nicotinic/drug effects
- Receptors, Nicotinic/physiology
- Thiopental/pharmacology
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Affiliation(s)
- Martin Weber
- School of Biomedical Sciences, University of Queensland, Brisbane, Queensland 4072, Australia
- Institut für Physiologie und Pathophysiologie, Abteilung Medizinische Biophysik, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 326, Heidelberg 69120, Germany
| | - Leonid Motin
- School of Biomedical Sciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Simon Gaul
- Institut für Physiologie und Pathophysiologie, Abteilung Medizinische Biophysik, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 326, Heidelberg 69120, Germany
| | - Friederike Beker
- School of Biomedical Sciences, University of Queensland, Brisbane, Queensland 4072, Australia
- Institut für Physiologie und Pathophysiologie, Abteilung Medizinische Biophysik, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 326, Heidelberg 69120, Germany
| | - Rainer H A Fink
- Institut für Physiologie und Pathophysiologie, Abteilung Medizinische Biophysik, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 326, Heidelberg 69120, Germany
| | - David J Adams
- School of Biomedical Sciences, University of Queensland, Brisbane, Queensland 4072, Australia
- Author for correspondence:
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DeHaven WI, Cuevas J. VPAC Receptor Modulation of Neuroexcitability in Intracardiac Neurons. J Biol Chem 2004; 279:40609-21. [PMID: 15280371 DOI: 10.1074/jbc.m404743200] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal polypeptide (VIP) have been found within mammalian intracardiac ganglia, but the cellular effects of these neuropeptides remain poorly understood. Fluorometric calcium imaging and whole cell patch clamp recordings were used to examine the effects of PACAP and VIP on [Ca2+]i and neuroexcitability, respectively, in intracardiac neurons of neonatal rats. PACAP and VIP evoked rapid increases in [Ca2+]i that exhibited both transient and sustained components. Pharmacological experiments using PAC1 and VPAC receptor-selective antagonists demonstrated that the elevations in [Ca2+]i result from the activation of VPAC receptors. The transient increases in [Ca2+]i were shown to be the product of Ca2+ mobilization from caffeine/ryanodine-sensitive intracellular stores and were not due to inositol 1,4,5-trisphosphate-mediated calcium release. In contrast, the sustained [Ca2+]i elevations were dependent on extracellular Ca2+ and were blocked by the transient receptor channel antagonist, 2-aminoethoxydiphenyl borate, which suggests that they are due to Ca2+ entry via store-operated channels. In addition to elevating [Ca2+]i, both PACAP and VIP depolarized intracardiac neurons, and PACAP was further shown to augment action potential firing in these cells. Depolarization of intracardiac neurons by the neuropeptides was dependent on activation of VPAC receptors and the concomitant increases in [Ca2+]i. Although activation of PAC1 receptors alone had no direct effects on neuroexcitability, PAC1 receptor stimulation potentiated the VPAC receptor-induced depolarizations. Furthermore, enhanced action potential firing was only observed upon concurrent stimulation of PAC1 and VPAC receptors, which indicates that these receptors act synergistically to enhance neuroexcitability in intracardiac neurons.
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Affiliation(s)
- Wayne I DeHaven
- Department of Pharmacology and Therapeutics, University of South Florida College of Medicine, Tampa, Florida 33612, USA
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Dajas-Bailador F, Wonnacott S. Nicotinic acetylcholine receptors and the regulation of neuronal signalling. Trends Pharmacol Sci 2004; 25:317-24. [PMID: 15165747 DOI: 10.1016/j.tips.2004.04.006] [Citation(s) in RCA: 437] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Neuronal nicotinic acetylcholine (nACh) receptors in the brain are more commonly associated with modulatory events than mediation of synaptic transmission. nACh receptors have a high permeability for Ca(2+), and Ca(2+) signals are pivotal in shaping nACh receptor-mediated neuromodulatory effects. In this review, we consider the mechanisms through which nACh receptors convert rapid ionic signals into sustained, wide-ranging phenomena. The complex Ca(2+) responses that are generated after activation of nACh receptors can transmit information beyond the initial domain and facilitate the interface with many intracellular processes. These mechanisms underlie the diverse repertoire of neuronal activities of nicotine in the brain, from the enhancement of learning and memory, to addiction and neuroprotection.
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