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Sévoz-Couche C, Liao W, Foo HYC, Bonne I, Lu TB, Tan Qi Hui C, Azhar SH, Peh WYX, Yen SC, Wong WSF. Direct vagus nerve stimulation: A new tool to control allergic airway inflammation through α7 nicotinic acetylcholine receptor. Br J Pharmacol 2024; 181:1916-1934. [PMID: 38430056 DOI: 10.1111/bph.16334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 11/24/2023] [Accepted: 01/08/2024] [Indexed: 03/03/2024] Open
Abstract
BACKGROUND AND PURPOSE Asthma is characterized by airway inflammation, mucus hypersecretion, and airway hyperresponsiveness. The use of nicotinic agents to mimic the cholinergic anti-inflammatory pathway (CAP) controls experimental asthma. Yet, the effects of vagus nerve stimulation (VNS)-induced CAP on allergic inflammation remain unknown. EXPERIMENTAL APPROACH BALB/c mice were sensitized and challenged with house dust mite (HDM) extract and treated with active VNS (5 Hz, 0.5 ms, 0.05-1 mA). Bronchoalveolar lavage (BAL) fluid was assessed for total and differential cell counts and cytokine levels. Lungs were examined by histopathology and electron microscopy. KEY RESULTS In the HDM mouse asthma model, VNS at intensities equal to or above 0.1 mA (VNS 0.1) but not sham VNS reduced BAL fluid differential cell counts and alveolar macrophages expressing α7 nicotinic receptors (α7nAChR), goblet cell hyperplasia, and collagen deposition. Besides, VNS 0.1 also abated HDM-induced elevation of type 2 cytokines IL-4 and IL-5 and was found to block the phosphorylation of transcription factor STAT6 and expression level of IRF4 in total lung lysates. Finally, VNS 0.1 abrogated methacholine-induced hyperresponsiveness in asthma mice. Prior administration of α-bungarotoxin, a specific inhibitor of α7nAChR, but not propranolol, a specific inhibitor of β2-adrenoceptors, abolished the therapeutic effects of VNS 0.1. CONCLUSION AND IMPLICATIONS Our data revealed the protective effects of VNS on various clinical features in allergic airway inflammation model. VNS, a clinically approved therapy for depression and epilepsy, appears to be a promising new strategy for controlling allergic asthma.
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Affiliation(s)
- Caroline Sévoz-Couche
- INSERM, UMRS1158 Neurophysiologie Respiratoire et Clinique, Sorbonne Université, Paris, France
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Wupeng Liao
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Singapore-HUJ Alliance for Research and Enterprise (SHARE), National University of Singapore, Singapore
| | - Hazel Y C Foo
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Singapore-HUJ Alliance for Research and Enterprise (SHARE), National University of Singapore, Singapore
| | - Isabelle Bonne
- Electron Microscopy Unit, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Department of Microbiology & Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Thong Beng Lu
- Electron Microscopy Unit, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Department of Microbiology & Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Caris Tan Qi Hui
- Advanced imaging and Histology Core, Immunology Program, Life Science Institute, National University of Singapore, Singapore
| | - Syaza Hazwany Azhar
- Advanced imaging and Histology Core, Immunology Program, Life Science Institute, National University of Singapore, Singapore
| | - Wendy Yen Xian Peh
- The N.1 Institute for Health, National University of Singapore, Singapore
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore
| | - Shih-Cheng Yen
- The N.1 Institute for Health, National University of Singapore, Singapore
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore
| | - W S Fred Wong
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Singapore-HUJ Alliance for Research and Enterprise (SHARE), National University of Singapore, Singapore
- Drug Discovery and Optimization Platform, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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Li M, Huang C, Wu X, Ding F, Hu Z, Zhu Y, Zhao L, Hou L, Chen H, Wang H, Xu J, Tang D. The optimization of a novel selective antagonist for human M 2 muscarinic acetylcholine receptor. Bioorg Med Chem Lett 2020; 30:127632. [PMID: 33132116 DOI: 10.1016/j.bmcl.2020.127632] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 10/14/2020] [Accepted: 10/16/2020] [Indexed: 01/22/2023]
Abstract
Muscarinic acetylcholine receptors (mAChRs) comprise five distinct subtypes denoted M1 to M5. The antagonism of M2 subtype could increase the release of acetylcholine from vesicles into the synaptic cleft and improve postsynaptic functions in the hippocampus via M1 receptor activation, displaying therapeutic potentials for Alzheimer's disease. However, drug development for M2 antagonists is still challenged among different receptor subtypes. In this study, by optimizing a scaffold from virtual screening, we synthesized two focused libraries and generated up to 50 derivatives. By measuring potency and binding selectivity, we discovered a novel M2 antagonist, ligand 47, featuring submicromolar IC50, high M2/M4 selectivity (~30-fold) and suitable lipophilicity (cLogP = 4.55). Further study with these compounds also illustrates the structure-activity relationship of this novel scaffold. Our study could not only provide novel lead structure, which was easy to synthesize, but also offer valuable information for further development of selective M2 ligands.
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Affiliation(s)
- Miaomiao Li
- Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Chen Huang
- Department of Nuclear Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, 160 Pu Jian Road, Shanghai 200127, China; College of Medical Imaging, Shanghai University of Medicine and Health Sciences, Shanghai 201318, China
| | - Xingyu Wu
- College of Pharmacy, Shanghai University of Medicine and Health Sciences, Shanghai 201318, China
| | - Fan Ding
- Department of Nuclear Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, 160 Pu Jian Road, Shanghai 200127, China
| | - Zhoumi Hu
- Department of Nuclear Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, 160 Pu Jian Road, Shanghai 200127, China
| | - Yan Zhu
- School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Lanxue Zhao
- Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Lina Hou
- Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Hongzhuan Chen
- Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China; Institute of Interdisciplinary Integrative Biomedical Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Hao Wang
- Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Jianrong Xu
- Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China; Academy of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China.
| | - Dewei Tang
- Department of Nuclear Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, 160 Pu Jian Road, Shanghai 200127, China.
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Smail MA, Soles JL, Karwoski TE, Rubin RT, Rhodes ME. Sexually diergic hypothalamic-pituitary-adrenal axis responses to selective and non-selective muscarinic antagonists prior to cholinergic stimulation by physostigmine in rats. Brain Res Bull 2017; 137:23-34. [PMID: 29122691 DOI: 10.1016/j.brainresbull.2017.11.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Revised: 10/21/2017] [Accepted: 11/02/2017] [Indexed: 01/02/2023]
Abstract
Central cholinergic systems regulate the hypothalamic-pituitary-adrenal (HPA) axis differentially in males and females (sexual diergism). We previously investigated the role of muscarinic receptors in this regulation by administering physostigmine (PHYSO), an acetylcholinesterase inhibitor, to male and female rats pretreated with scopolamine (SCOP), a nonselective muscarinic antagonist. SCOP pretreatment enhanced adrenocorticotropic hormone (ACTH) and corticosterone (CORT) responses in both sexes, but males had greater ACTH responses while females had greater CORT responses. In the present study, we further explored the role of muscarinic receptor subtypes in HPA axis regulation by administering PHYSO to male and female rats following SCOP or various doses of either the M1 or the M2 selective muscarinic receptor antagonists, pirenzepine (PIREN) or methoctramine (METHO). Blood was sampled before and at multiple times after PHYSO. ACTH and CORT were determined by highly specific immunoassays. M1 antagonism by PIREN prior to PHYSO resulted in sustained, dose-dependent increases in ACTH and CORT: ACTH responses were similar in both sexes, and CORT responses were greater in females. M2 antagonism by METHO prior to PHYSO resulted in overall decreases in ACTH and CORT: ACTH and CORT responses were higher in females but lower in both sexes than the hormone responses following PIREN or SCOP pretreatment. Area under the curve analyses supported these findings. These results suggest that specific muscarinic receptor subtypes differentially influence the HPA axis in a sexually diergic manner.
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Affiliation(s)
- Marissa A Smail
- Department of Biology, Saint Vincent College, Latrobe, PA, United States
| | - Jessica L Soles
- Department of Biology, Saint Vincent College, Latrobe, PA, United States
| | - Tracy E Karwoski
- Center for Neurosciences Research, Allegheny General Hospital, Pittsburgh, PA, United States
| | - Robert T Rubin
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Michael E Rhodes
- Department of Biology, Saint Vincent College, Latrobe, PA, United States.
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4
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Cazzola M, Calzetta L, Puxeddu E, Ora J, Facciolo F, Rogliani P, Matera MG. Pharmacological characterisation of the interaction between glycopyrronium bromide and indacaterol fumarate in human isolated bronchi, small airways and bronchial epithelial cells. Respir Res 2016; 17:70. [PMID: 27296533 PMCID: PMC4906998 DOI: 10.1186/s12931-016-0386-8] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 06/03/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Nowadays, there is a considerable gap in knowledge concerning the mechanism(s) by which long-acting β2-agonists (LABAs) and long-acting muscarinic antagonists (LAMAs) interact to induce bronchodilation. This study aimed to characterise the pharmacological interaction between glycopyrronium bromide and indacaterol fumarate and to identify the mechanism(s) leading to the bronchorelaxant effect of this interaction. METHODS The effects of glycopyrronium plus indacaterol on the contractile tone of medium and small human isolated bronchi were evaluated, and acetylcholine and cAMP concentrations were quantified. The interaction was assessed by Bliss Independence approach. RESULTS Glycopyrronium plus indacaterol synergistically inhibited the bronchial tone (medium bronchi, +32.51 % ± 7.86 %; small bronchi, +28.46 % ± 5.35 %; P < 0.05 vs. additive effect). The maximal effect was reached 140 min post-administration. A significant (P < 0.05) synergistic effect was observed during 9 h post-administration on the cholinergic tone, but not on the histaminergic contractility. Co-administration of glycopyrronium and indacaterol reduced the release of acetylcholine from the epithelium but not from bronchi, and enhanced cAMP levels in bronchi and epithelial cells (P < 0.05 vs. control), an effect that was inhibited by the selective KCa(++) channel blocker iberiotoxin. The role of cAMP-dependent pathway was confirmed by the synergistic effect elicited by the adenylate cyclase activator forskolin on glycopyrronium (P < 0.05 vs. additive effect), but not on indacaterol (P > 0.05 vs. additive effect), with regard of the bronchial relaxant response and cAMP increase. CONCLUSIONS Glycopyrronium/indacaterol co-administration leads to a synergistic improvement of bronchodilation by increasing cAMP concentrations in both airway smooth muscle and bronchial epithelium, and by decreasing acetylcholine release from the epithelium.
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Affiliation(s)
- Mario Cazzola
- Department of Systems Medicine, Chair of Respiratory Medicine, University of Rome Tor Vergata, Rome, Italy.,Department of Systems Medicine, Respiratory Pharmacology Research Unit, University of Rome Tor Vergata, Via Montpellier 1, 00133, Rome, Italy.,Division of Respiratory Medicine, University Hospital Tor Vergata, Rome, Italy
| | - Luigino Calzetta
- Department of Systems Medicine, Respiratory Pharmacology Research Unit, University of Rome Tor Vergata, Via Montpellier 1, 00133, Rome, Italy.
| | - Ermanno Puxeddu
- Department of Systems Medicine, Chair of Respiratory Medicine, University of Rome Tor Vergata, Rome, Italy.,Division of Respiratory Medicine, University Hospital Tor Vergata, Rome, Italy
| | - Josuel Ora
- Division of Respiratory Medicine, University Hospital Tor Vergata, Rome, Italy
| | - Francesco Facciolo
- Regina Elena National Cancer Institute, Thoracic Surgery Unit, Rome, Italy
| | - Paola Rogliani
- Department of Systems Medicine, Chair of Respiratory Medicine, University of Rome Tor Vergata, Rome, Italy.,Division of Respiratory Medicine, University Hospital Tor Vergata, Rome, Italy
| | - Maria Gabriella Matera
- Department of Experimental Medicine, Unit of Pharmacology, Second University of Naples, Naples, Italy
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6
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POSTER COMMUNICATIONS. Br J Pharmacol 2012. [DOI: 10.1111/j.1476-5381.1992.tb16283.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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7
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Li Y, Lein PJ, Liu C, Bruun DA, Tewolde T, Ford G, Ford BD. Spatiotemporal pattern of neuronal injury induced by DFP in rats: a model for delayed neuronal cell death following acute OP intoxication. Toxicol Appl Pharmacol 2011; 253:261-9. [PMID: 21513723 DOI: 10.1016/j.taap.2011.03.026] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 03/25/2011] [Accepted: 03/31/2011] [Indexed: 01/16/2023]
Abstract
Organophosphate (OP) neurotoxins cause acute cholinergic toxicity and seizures resulting in delayed brain damage and persistent neurological symptoms. Testing novel strategies for protecting against delayed effects of acute OP intoxication has been hampered by the lack of appropriate animal models. In this study, we characterize the spatiotemporal pattern of cellular injury after acute intoxication with the OP diisopropylfluorophosphate (DFP). Adult male Sprague-Dawley rats received pyridostigmine (0.1 mg/kg, im) and atropine methylnitrate (20mg/kg, im) prior to DFP (9 mg/kg, ip) administration. All DFP-treated animals exhibited moderate to severe seizures within minutes after DFP injection but survived up to 72 h. AChE activity was significantly depressed in the cortex, hippocampus, subcortical brain tissue and cerebellum at 1h post-DFP injection and this inhibition persisted for up to 72 h. Analysis of neuronal injury by Fluoro-Jade B (FJB) labeling revealed delayed neuronal cell death in the hippocampus, cortex, amygdala and thalamus, but not the cerebellum, starting at 4h and persisting until 72 h after DFP treatment, although temporal profiles varied between brain regions. At 24h post-DFP injection, the pattern of FJB labeling corresponded to TUNEL staining in most brain regions, and FJB-positive cells displayed reduced NeuN immunoreactivity but were not immunopositive for astrocytic (GFAP), oligodendroglial (O4) or macrophage/microglial (ED1) markers, demonstrating that DFP causes a region-specific delayed neuronal injury mediated in part by apoptosis. These findings indicate the feasibility of this model for testing neuroprotective strategies, and provide insight regarding therapeutic windows for effective pharmacological intervention following acute OP intoxication.
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Affiliation(s)
- Yonggang Li
- Department of Neurobiology, Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA 30310, USA
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8
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Card JW, Voltz JW, Ferguson CD, Carey MA, DeGraff LM, Peddada SD, Morgan DL, Zeldin DC. Male sex hormones promote vagally mediated reflex airway responsiveness to cholinergic stimulation. Am J Physiol Lung Cell Mol Physiol 2006; 292:L908-14. [PMID: 17158599 PMCID: PMC2066189 DOI: 10.1152/ajplung.00407.2006] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
A sex disparity in airway responsiveness to cholinergic stimulation has been observed in laboratory mice in that males are considerably more responsive than females, but the basis for this difference is unclear. In this report, we demonstrate that male sex hormones promote murine airway responsiveness to cholinergic stimulation via vagus nerve-mediated reflex mechanisms. In tissue bath preparations, no sex-based differences were observed in the contractile responses of isolated tracheal and bronchial ring segments to carbachol, indicating that the mechanism(s) responsible for the in vivo sex difference is (are) absent ex vivo. Bilateral cervical vagotomy was found to abolish in vivo airway responsiveness to methacholine in male mice, whereas it did not alter the responses of females, suggesting a regulatory role for male sex hormones in promoting reflex airway constriction. To test this possibility, we next studied mice with altered circulating male sex hormone levels. Castrated male mice displayed airway responsiveness equivalent to that observed in intact females, whereas administration of exogenous testosterone to castrated males restored responsiveness, albeit not to the level observed in intact males. Administration of exogenous testosterone to intact female mice similarly enhanced responsiveness. Importantly, the promotive effects of exogenous testosterone in castrated male and intact female mice were absent when bilateral vagotomy was performed. Together, these data indicate that male sex hormones promote cholinergic airway responsiveness via a vagally mediated reflex mechanism that may be important in the regulation of airway tone in the normal and diseased lung.
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Affiliation(s)
- Jeffrey W Card
- Division of Intramural Research, National Institute of Environmental Health Sciences, 111 T.W. Alexander Dr., Bldg. 101, Rm. D236, Research Triangle Park, NC 27709, USA
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9
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Billington CK, Penn RB. Signaling and regulation of G protein-coupled receptors in airway smooth muscle. Respir Res 2003. [DOI: 10.1186/1465-9921-4-2] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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10
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Billington CK, Penn RB. Signaling and regulation of G protein-coupled receptors in airway smooth muscle. Respir Res 2003; 4:2. [PMID: 12648290 PMCID: PMC152647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2002] [Revised: 10/09/2002] [Accepted: 10/14/2002] [Indexed: 11/27/2022] Open
Abstract
Signaling through G protein-coupled receptors (GPCRs) mediates numerous airway smooth muscle (ASM) functions including contraction, growth, and "synthetic" functions that orchestrate airway inflammation and promote remodeling of airway architecture. In this review we provide a comprehensive overview of the GPCRs that have been identified in ASM cells, and discuss the extent to which signaling via these GPCRs has been characterized and linked to distinct ASM functions. In addition, we examine the role of GPCR signaling and its regulation in asthma and asthma treatment, and suggest an integrative model whereby an imbalance of GPCR-derived signals in ASM cells contributes to the asthmatic state.
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Affiliation(s)
- Charlotte K Billington
- Department of Medicine, Division of Critical Care, Pulmonary, Allergic & Immunologic Diseases, and Kimmel Cancer Center, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 19107
| | - Raymond B Penn
- Department of Medicine, Division of Critical Care, Pulmonary, Allergic & Immunologic Diseases, and Kimmel Cancer Center, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 19107
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11
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Canning BJ. Nicotinic acetylcholine receptor assays. CURRENT PROTOCOLS IN PHARMACOLOGY 2001; Chapter 4:Unit 4.12. [PMID: 21965068 DOI: 10.1002/0471141755.ph0412s04] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Nicotinic acetylcholine receptors (nAChRs) in peripheral tissues are localized almost exclusively to autonomic nerves and the motor end plates of striated musculature. Pharmacologic analyses of nicotinic receptor antagonist potencies can be conducted by assessing the ability of these compounds to inhibit responses elicited by preganglionic autonomic nerve stimulation or stimulation of the motor nerves innervating striated muscle in isolated tissue preparations. In addition, in some isolated tissues innervated by autonomic nerves, nicotinic receptor mediated responses can be elicited by exogenously administered agonists, and the effects of antagonists on these responses can be assessed using pharmacologic analyses. This unit describes the guinea pig trachea/esophagus preparation, in which nicotinic receptor pharmacology can be studied at synapses of the parasympathetic and sympathetic nervous system and the striated musculature of the esophagus. In addition, a preparation whereby the nicotinic receptors of the striated musculature of the diaphragm can be studied is described as are techniques for studying exogenous nicotinic agonist mediated effects in two smooth muscle preparations.Nicotinic acetylcholine receptors (nAChRs) in peripheral tissues are localized almost exclusively to autonomic nerves.
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Affiliation(s)
- B J Canning
- The Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
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12
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Preuss JM, Goldie RG. Muscarinic cholinoceptor subtypes mediating tracheal smooth muscle contraction and inositol phosphate generation in guinea pig and rat. Eur J Pharmacol 1999; 372:269-77. [PMID: 10395022 DOI: 10.1016/s0014-2999(99)00213-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The effects of the muscarinic cholinoceptor antagonists atropine (non-selective), pirenzepine (M1-selective), methoctramine (M2-selective) and 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP; M3-selective) were examined on the responsiveness of guinea pig and rat tracheal tissue to acetylcholine and carbachol. Results indicate that smooth muscle contraction in isolated tracheal tissue from both species was mediated primarily by muscarinic M3 cholinoceptors. The effects of atropine, pirenzepine and 4-DAMP were similar against the contractile actions of acetylcholine and carbachol in both species and in epithelium-intact and epithelium-denuded tissue. In contrast, differences in the effects of methoctramine in antagonising contractile responses to acetylcholine and carbachol were observed between the two species and following epithelium removal in the guinea pig. Thus, whilst this study has found that tracheal smooth muscle contraction in the guinea pig and rat is mediated primarily by muscarinic M3 cholinoceptors, anomalies in the functional inositol phosphate generation results obtained with the muscarinic cholinoceptor antagonists highlight species differences in the actions of acetylcholine and carbachol in eliciting smooth muscle contraction suggesting the possible existence of functional non-M3 muscarinic cholinoceptors.
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Affiliation(s)
- J M Preuss
- Department of Pharmacology, University of Western Australia, Nedlands, Perth, Australia.
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13
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Costello RW, Evans CM, Yost BL, Belmonte KE, Gleich GJ, Jacoby DB, Fryer AD. Antigen-induced hyperreactivity to histamine: role of the vagus nerves and eosinophils. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 276:L709-14. [PMID: 10330026 DOI: 10.1152/ajplung.1999.276.5.l709] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
M2 muscarinic receptors limit acetylcholine release from the pulmonary parasympathetic nerves. M2 receptors are dysfunctional in antigen-challenged guinea pigs, causing increased vagally mediated bronchoconstriction. Dysfunction of these M2 receptors is due to eosinophil major basic protein, which is an antagonist for M2 receptors. Histamine-induced bronchoconstriction is composed of a vagal reflex in addition to its direct effect on airway smooth muscle. Because hyperreactivity to histamine is seen in antigen-challenged animals, we hypothesized that hyperreactivity to histamine may be due to increased vagally mediated bronchoconstriction caused by dysfunction of M2 receptors. In anesthetized, antigen-challenged guinea pigs, histamine-induced bronchoconstriction was greater than that in control guinea pigs. After vagotomy or atropine treatment, the response to histamine in antigen-challenged animals was the same as that in control animals. In antigen-challenged animals, blockade of eosinophil influx into the airways or neutralization of eosinophil major basic protein prevented the development of hyperreactivity to histamine. Thus hyperreactivity to histamine in antigen-challenged guinea pigs is vagally mediated and dependent on eosinophil major basic protein.
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Affiliation(s)
- R W Costello
- Department of Environmental Health Sciences, School of Hygiene and Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA
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14
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Melchiorre C, Minarini A, Budriesi R, Chiarini A, Spampinato S, Tumiatti V. The design of novel methoctramine-related tetraamines as muscarinic receptor subtype selective antagonists. Life Sci 1999; 56:837-44. [PMID: 10188783 DOI: 10.1016/0024-3205(95)00018-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Several novel methoctramine-related tetraamines were designed, and their biological profiles at muscarinic receptor subtypes were assessed by functional experiments in isolated guinea pig and rat atria (M2) and smooth muscle (ileum and trachea, M3) and by binding assays in rat cortex (M1), heart (M2), and submaxillary gland (M3) homogenates and NG 108-15 cells (M4). Tripitramine, a nonsymmetrical tetraamine, resulted in the most potent and the most selective muscarinic M2 receptor antagonist of the series (pA2 = 9.14-9.85; pKi = 9.54). Spirotramine (FC 15-94), a symmetrical tetraamine, was able to differentiate between muscarinic M1 receptors (pKi = 7.88) and the other subtypes (M2, pKi = 6.20; M3, pKi = 5.81; M4, pKi = 6.27). Thus, tripitramine and spirotramine could be valuable tools for the pharmacological classification and characterization of muscarinic receptor subtypes.
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Affiliation(s)
- C Melchiorre
- Department of Pharmaceutical Sciences, University of Bologna, Italy
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15
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Tayebati SK, Piergentili A, Natale D, Amenta F. Evaluation of an agonist index: affinity ratio for compounds active on muscarinic cholinergic M2 receptors. JOURNAL OF AUTONOMIC PHARMACOLOGY 1999; 19:77-84. [PMID: 10466939 DOI: 10.1046/j.1365-2680.1999.00118.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A protocol for predicting full agonist, partial agonist, and antagonist profiles of compounds with M2 muscarinic cholinergic receptor activity was developed using radioligand binding assay techniques with [3H]-N-methyl scopolamine (NMS) and [3H]-Oxotremorine-M (Oxo-M) as radioligands. Full muscarinic cholinergic receptor agonists such as muscarine and oxotremorine-M expressed a high agonist index (> 3000 for M1 muscarinic cholinergic receptors and > 900 for M2 muscarinic cholinergic receptor), whereas muscarinic receptor antagonists (selective or non-selective) for different receptor subtypes gave a low (0.5-10) agonist index. Functional studies performed on preparations of guinea-pig ileum and heart were consistent with radioligand binding assay experiments. The above results suggest that similarly as already established for the M1 muscarinic cholinergic receptor subtype, evaluation of the [3H]-NMS/[3H]-Oxo-M ratio may provide useful information on the profile of compounds acting at the M2 muscarinic cholinergic receptor subtype. The availability of simple and predictive techniques for the characterization of muscarinic M2 cholinergic receptor agonists, may help the identification of new compounds in therapeutic areas in which stimulation or inhibition of this receptor is desirable.
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Affiliation(s)
- S K Tayebati
- Sezione di Anatomia Umana, Dipartimento di Scienze Farmacologiche e Medicina Sperimentale, Camerino, Italy
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Matera MG, D'Agostino B, Costantino M, Amorena M, Lucarelli C, Rossi F. Possible functional modulation by acetylcholine of nitric oxide on guinea pig isolated trachea. Life Sci 1998; 62:553-9. [PMID: 9464468 DOI: 10.1016/s0024-3205(97)01152-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The aim of this study was to evaluate whether acetylcholine induces NO release. We determined the responses on the cholinergic component of the response to electrical field stimulation (EFS) the effects of L-nitro-arginine-methyl-ester (L-NAME; 1 mM), an inhibitor of NO synthase, of L-Arginine (L-ARG; 1 mM), a precursor of NO synthesis, and methoctramine (0.01-0.1-1 microM), an antagonist of M2 receptors, alone or associated with L-NAME. The experiments were performed on guinea pig isolated intact- or denuded-epithelium tracheal rings contracted in a frequency-dependent manner to EFS. At the maximum frequency tested (30 Hz), the contractile response elicited was 60.36 +/- 0.61% of acetylcholine (100 microM) contraction, while the maximal relaxant effect induced by EFS was -28.40 +/- 0.61% in epithelium intact preparations. A pretreatment with L-NAME significantly (P<0.05) increased the contraction (76.08 +/- 1.39%) and reduced the relaxation elicited by EFS. L-NAME effect on both EFS induced responses were statistically (P<0.05) reversed by the association L-NAME + L-ARG. Methoctramine (1 microM) enhanced contractile (P<0.05) (79.20 +/- 2.21%), as well as relaxant responses (-38.73 +/- 0.99%) elicited by EFS in guinea pig epithelium-intact tracheal rings; in a separate series of experiments, performed on guinea pig epithelium-intact rings, L-NAME increased the contractile responses to methoctramine (82.6 +/- 2.31), but reduced the relaxant ones (26.38 +/- 1.29). In contrast, at the maximum frequency tested, it increased only the contractile response, but not modify the relaxant one, in epithelium denuded rings. In conclusion, the present data showed that the release of acetylcholine from postganglionic cholinergic nerves plays an important role on NO formation and this effect may be modulate by epithelium.
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Affiliation(s)
- M G Matera
- Institute of Pharmacology and Toxicology - Faculty of Medicine - 2nd University of Naples, Italy
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17
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Roffel AF, Davids JH, Elzinga CR, Wolf D, Zaagsma J, Kilbinger H. Characterization of the muscarinic receptor subtype(s) mediating contraction of the guinea-pig lung strip and inhibition of acetylcholine release in the guinea-pig trachea with the selective muscarinic receptor antagonist tripitramine. Br J Pharmacol 1997; 122:133-41. [PMID: 9298539 PMCID: PMC1564905 DOI: 10.1038/sj.bjp.0701346] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
1. The muscarinic receptor subtypes mediating contraction of the guinea-pig lung strip and inhibition of the release of acetylcholine from cholinergic vagus nerve endings in the guinea-pig trachea in vitro have previously been characterized as M2-like, i.e. having antagonist affinity profiles that are qualitatively similar but quantitatively dissimilar compared to cardiac M2 receptors. The present study sought to establish definitely the identity of these receptor subtypes by using the selective muscarinic receptor antagonist, tripitramine. Guinea-pig atria and guinea-pig trachea (postjunctional contractile response) were included for reference. 2. It was found that tripitramine antagonized methacholine-induced contractions of the guinea-pig lung strip with pKB value of 8.76 +/- 0.05. Both the parallel shifts of the concentration-response curves and the slope of the Schild plot begin not significantly different from unity (when antagonist preincubation was for 2 h) indicated the involvement of a single population of receptors in the contractile response. From the pKB values obtained with tripitramine and a range of other selective muscarinic receptor antagonists (cf. Roffel et al., 1993), this single population of receptors can only be classified as M2-like. 3. Tripitramine antagonized methacholine-induced chronotropic and inotropic responses in guinea-pig right and left atria with apparent pKB values of 9.4-9.6. However, such values were only obtained when antagonist preincubation was relatively long and/or antagonist concentration relatively high (e.g with 1 h at 100 or 300 nM but 3 h at 30 nM). It thus appears that low concentrations of tripitramine do not readily equilibrate with M2 receptors in guinea-pig atria nor with M2-like receptors in the guinea-pig lung strip. 4. Tripitramine increased electrical field stimulation-induced cholinergic twitch contractions in guinea-pig trachea in concentrations of 0.3-100 nM, by blocking prejunctional muscarinic inhibitory autoreceptors; with higher concentrations, twitch contractions were progressively diminished, as a result of blocking postjunctional M3 receptors (apparent pKB value 6.07 +/- 0.15). The pEC20 value (-log concentration that increases twitch by 20% maximum) was 8.29 +/- 0.08, which would suggest that M4 receptors are involved in this response. 5. Oxotremorine-induced inhibition of the release of prelabelled [3H]-acetylcholine from guinea-pig trachea, under conditions where there is no auto-feedback, was blocked by tripitramine (2 h preincubation) with a pKB value of 8.56 +/- 0.06. The slope of the corresponding Schild plot was not significantly different from unity, which together with the parallel shifts of the concentration-response curves indicated the involvement of a single muscarinic receptor subtype. 6. Since the pKB value for tripitramine at prejunctional receptors in guinea-pig trachea is in between the affinities towards M2 and M4 receptors, correlation plots were constructed to compare the pKB values obtained with tripitramine and a range of other selective muscarinic receptor antagonists (cf. Kilbinger et al., 1995) to reported affinities at M1-M4 receptors. This showed rather similar distribution patterns of the data points around the line of equality in the case of M2 and M4 receptor subtypes. However, the correlation coefficient was markedly better for M2 (0.9667) than for M4 (0.5976). Since recent evidence suggests that M4 receptors are not expressed in cholinergic nerves from guinea-pig trachea, it is concluded that prejunctional muscarinic autoinhibitory receptors in this tissue exhibit an atypical M2 type character, with a pharmacological profile distinct from cardiac M2 receptors.
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Affiliation(s)
- A F Roffel
- Department of Molecular Pharmacology, University of Groningen, The Netherlands
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18
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Abstract
Muscarinic M1, M2, and M3 receptor subtypes have been shown to be involved in the pre- and postjunctional control of airway diameter of various species, including man. In a guinea pig model of allergic asthma, the prejunctional M2 receptor was shown to become dysfunctional already during the early allergic reaction, thereby contributing to exaggerated vagal reflex activity and airway hyperreactivity. Moreover, a deficiency of endogenous nitric oxide was observed after allergen provocation, which may also contribute to an enhanced postjunctional M3 receptor-mediated cholinergic response. Both in human and in animal airway preparations it was shown that enhanced cholinergic contractions are relatively resistent to beta-adrenoceptor-mediated relaxation. The reduced beta-adrenoceptor function may primarily be due to transductional cross-talk between PI metabolism and adenylyl cyclase, including protein kinase C-induced uncoupling of the beta-adrenoceptor from the effector system. Cross-talk between postjunctional M2 receptor-mediated inhibition and beta-adrenoceptor-induced activation of adenylyl cyclase appears to be of minor functional importance, but could be enhanced in allergic asthma due to increased expression of the inhibitory G protein as induced by cytokines.
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Affiliation(s)
- J Zaagsma
- Department of Molecular Pharmacology, University Centre for Pharmacy, Groningen, The Netherlands
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19
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Nasa Y, Kume H, Takeo S. Acetylcholine-induced vasoconstrictor response of coronary vessels in rats: a possible contribution of M2 muscarinic receptor activation. Heart Vessels 1997; 12:179-91. [PMID: 9559968 DOI: 10.1007/bf02767046] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A mechanism by which acetylcholine (ACh) may elicit vasoconstrictor response in coronary vessels was studied in rat hearts perfused at a constant flow rate. In spontaneously beating hearts, bolus injections of ACh and carbachol (CCh) produced biphasic changes in coronary perfusion pressure (CPP): a transient increase at the initial period followed by a sustained decrease. In KCl-arrested hearts, ACh and CCh produced a monophasic increase in CPP, which was attenuated by either removal of endothelial cells by saponin or cyclooxygenase inhibition by diclofenac sodium. In the spontaneously beating heart, ACh-induced vasoconstriction was almost abolished by atropine (0.1 microM) and was markedly attenuated by an M2 antagonist, methoctramine (0.1 microM), but not by an M1 antagonist, pirenzepine (1 microM). Arecaidine propargyl ester (APE), an M2 agonist, produced coronary artery constriction which was attenuated by methoctramine (0.1 microM) but not by pirenzepine (0.1 microM) in both spontaneously beating and KCl-arrested hearts. McN-A-343, an M1 agonist, increased CPP in both beating and KCl-arrested hearts, but to a lesser degree than APE. These results suggest that the release of vasoconstrictor prostaglandins from endothelial cells contributes to the vasoconstrictor response to ACh in perfused rat coronary vessels, and the response to ACh appears to be mediated, in part, via the M2 subtype of muscarinic receptors.
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Affiliation(s)
- Y Nasa
- Department of Pharmacology, Tokyo University of Pharmacy and Life Science, Hachioji, Japan
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20
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ten Berge RE, Weening EC, Roffel AF, Zaagsma J. Differences in the prejunctional effects of methacholine and pilocarpine on the release of endogenous acetylcholine from guinea-pig trachea. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 1996; 354:606-11. [PMID: 8938659 DOI: 10.1007/bf00170835] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We investigated the effects of the full muscarinic acetylcholine receptor agonist methacholine and the partial and putatively M2-selective agonist pilocarpine on endogenous acetylcholine release from guinea-pig trachea by use of high-performance liquid chromatography with electrochemical detection. Atropine-induced increases in acetylcholine release were used to monitor the system. Electrical field stimulation (8 V, 30 Hz, 0.5 ms for 5 min)-induced acetylcholine release in the presence of neostigmine, with or without preincubation with choline to maximally enhance acetylcholine output, was increased to about 225% by 0.3 microM atropine, indicating functional autoinhibition. However, methacholine (10 microM) did not affect the acetylcholine release, whereas it was enhanced to 166% by 30 microM pilocarpine. When electrical field stimulation was applied at lower intensity (8 V, 16 Hz, 0.1 ms for 5 min) and in the absence of neostigmine, and increase by 0.3 microM atropine (to 177%) but a decrease of the acetylcholine release by 10 microM methacholine (to 65%) and 30 microM pilocarpine (to 63%) were observed. These results clearly demonstrate (i) that inhibition of evoked endogenous acetylcholine release from prejunctional nerve terminals in guinea-pig trachea can only be demonstrated under conditions of low junctional concentrations of acetylcholine, and (ii) that pilocarpine, as a partial muscarinic agonist, behaves as an antagonist under high junctional concentrations of the neurotransmitter.
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Affiliation(s)
- R E ten Berge
- Department of Molecular Pharmacology, University of Groningen, The Netherlands
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21
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Harriss D, Marsh K, Birmingham A, Hill S. Expression of Muscarinic M sub 3 -Receptors Coupled to Inositol Phospholipid Hydrolysis in Human Detrusor Cultured Smooth Muscle Cells. J Urol 1995. [DOI: 10.1016/s0022-5347(01)67039-3] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- D.R. Harriss
- Department of Physiology and Pharmacology, Medical School, Queen's Medical Centre, Nottingham, United Kingdom
| | - K.A. Marsh
- Department of Physiology and Pharmacology, Medical School, Queen's Medical Centre, Nottingham, United Kingdom
| | - A.T. Birmingham
- Department of Physiology and Pharmacology, Medical School, Queen's Medical Centre, Nottingham, United Kingdom
| | - S.J. Hill
- Department of Physiology and Pharmacology, Medical School, Queen's Medical Centre, Nottingham, United Kingdom
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22
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Chiarini A, Budriesi R, Bolognesi ML, Minarini A, Melchiorre C. In vitro characterization of tripitramine, a polymethylene tetraamine displaying high selectivity and affinity for muscarinic M2 receptors. Br J Pharmacol 1995; 114:1507-17. [PMID: 7606355 PMCID: PMC1510296 DOI: 10.1111/j.1476-5381.1995.tb13378.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
1. The antimuscarinic effects of tripitramine were investigated in vitro in isolated driven left (force) and spontaneously beating right (force and rate) atria as well as in the ileum of guinea-pig and rat and in the trachea and lung strip of guinea-pig and compared with the effects of methoctramine. 2. Tripitramine was a potent competitive antagonist of muscarinic M2 receptors in right and left atria. The pA2 values ranged from 9.14 to 9.85. However, in the guinea-pig and rat left atria but not in guinea-pig right atria, tripitramine at lower concentrations (3-10 nM) produced a less than proportional displacement to the right of agonist-induced responses owing to the presence of a possible saturable removal process. 3. Tripitramine was about three orders of magnitude less potent in ileal and tracheal than in atrial preparations (pA2 values ranging from 6.34 to 6.81) which makes it more potent and more selective than methoctramine. 4. Another intriguing finding was the observation that the pA2 value of 7.91 observed for tripitramine in guinea-pig lung does not correlate with that found at both muscarinic M2 and M3 receptor subtypes, which clearly indicates that the contraction of guinea-pig lung strip is not mediated by these muscarinic receptor subtypes. 5. A combination of tripitramine with atropine resulted in addition of the dose-ratios for left atria as required for two antagonists interacting competitively with the same receptor site, whereas the same combination gave a supra-additive antagonism on guinea-pig ileum which suggests that tripitramine interacts with a second interdependent site. 6. Tripitramine was more specific than methoctramine since, in addition to muscarinic receptors, it inhibited only frog rectus abdominis muscular (pIC50 value of 6.14) and rat duodenum neuronal (pIC50 value of 4.87) nicotinic receptors among receptor systems investigated, namely alpha 1-, alpha 2-, and beta 1-adrenoceptors, H1- and H2-histamine receptors, and muscular and neuronal nicotinic receptors.
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Affiliation(s)
- A Chiarini
- Department of Pharmaceutical Sciences, University of Bologna, Italy
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23
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Howell RE, Kovalsky MP. Hypotensive effect of an M2-selective muscarinic antagonist in anaesthetized guinea-pigs. JOURNAL OF AUTONOMIC PHARMACOLOGY 1995; 15:19-26. [PMID: 7744887 DOI: 10.1111/j.1474-8673.1995.tb00344.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
1. In order to determine an involvement of muscarinic M2 receptors in the regulation of systemic arterial blood pressure, we investigated the cardiovascular effects of the M2-selective antagonist methoctramine and other agents in anaesthetized guinea-pigs. 2. Intravenous injection of methoctramine, atropine, pirenzepine (an M1-selective muscarinic antagonist) or 4-DAMP (an M3-selective muscarinic antagonist) each significantly increased heart rate in comparison to vehicle controls. 3. Methoctramine produced significant, dose-dependent decreases in mean arterial blood pressure, with an ED50 of 0.1 mg kg-1. Atropine decreased blood pressure only at high doses. Pirenzepine and 4-DAMP did not alter blood pressure, indicating that M1 or M3 receptor antagonism was not responsible for the cardiovascular effects of methoctramine. 4. The hypotensive effect of methoctramine was unaltered by indomethacin pretreatment, ruling out an alteration in arachidonic acid metabolism as the mechanism of action. 5. In contrast to methoctramine, mecamylamine (a nicotinic ganglionic receptor antagonist) greatly decreased heart rate and slightly decreased blood pressure, suggesting that ganglionic blockade was not the mechanism for the cardiovascular effects of methoctramine. 6. Methoctramine (0.3 mg kg-1) pretreatment did not alter the hypertensive effect of intravenous noradrenaline, demonstrating that methoctramine did not directly inhibit vascular reactivity and indicating an indirect hypotensive of action of methoctramine. 7. In summary, the results suggest that the hypotensive action of methoctramine resulted from selective M2 receptor antagonism. Therefore, muscarinic M2 receptors appear to play a role in the regulation of systemic arterial blood pressure in guinea-pigs. However, the anatomical site(s) of action of methoctramine remains to be determined.
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Affiliation(s)
- R E Howell
- Nova Pharmaceutical Corporation, Baltimore, MD 21224, USA
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24
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Fisher JT, Froese AB, Brundage KL. [Physiological basis for the use of muscarine antagonists in bronchopulmonary dysplasia]. Arch Pediatr 1995; 2 Suppl 2:163S-171S. [PMID: 7633558 DOI: 10.1016/0929-693x(96)89886-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The rationale for the use of muscarinic antagonists in bronchopulmonary dysplasia (BPD) is based on the physiology and pharmacology of airway smooth muscle, the pathology of BPD, and the response of infants with BPD to bronchodilators, in vivo and in vitro studies of airway smooth muscle of newborn animals and humans indicate that vagal efferent airway innervation and/or muscarinic receptors are functional at birth, as well as early in gestation. Current concepts regarding muscarinic receptor subtypes suggest that M3 receptors mediate airway smooth muscle contraction, M2 receptors are autoinhibitory and limit vagally-mediated bronchoconstriction, and M1 receptors may play a facilitatory role in ganglionic transmission. Muscarinic receptor subtypes appear to be functionally expressed at birth but may undergo developmental regulation. Infants with BPD have an elevated pulmonary resistance that is accompanied by hypertrophy of airway smooth muscle, b2-agonists cause bronchodilation in BPD as does atropine in infants recovering from severe BPD. The synthetic congener of atropine, ipratropium bromide (IPB) causes bronchodilation in ventilator-dependent infants with BPD in a dose-dependent fashion. Nebulized IPB causes a decrease in respiratory resistance that reaches a maximum of 20% at 175 mg. The bronchodilation seen with muscarinic antagonists suggests that part of the elevated resistance associated with BPD is due to increased muscarinic tone, presumably vagal in origin. When IPB is combined with salbutamol (0.04 mg) the response is increased in magnitude and duration; reaching a slightly larger decreases in resistance (26%) that is now accompanied by an increase in compliance (20%).(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J T Fisher
- Département de physiologie, d'anesthésie et de pédiatrie de l'université Queen, Kingston, Ontario, Canada
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25
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Howell RE, Kovalsky MP, Laemont KD. Methoctramine induces nonspecific airway hyperresponsiveness in vivo. Eur J Pharmacol 1994; 265:67-75. [PMID: 7883031 DOI: 10.1016/0014-2999(94)90224-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We investigated the effects of subtype-selective muscarinic receptor antagonists upon aerosol antigen-induced bronchoconstriction in anesthetized guinea pigs. Neither pirenzepine (muscarinic M1 receptor-selective), 4-methylpiperidine methiodide (4-DAMP, muscarinic M3 receptor-selective), [N-iminomethyl-N'-[(2-hydroxy-2-phenyl-2-cyclohexyl)-ethyl] piperazine HCl (DAC-5945, muscarinic M3 receptor-selective), ipratropium or atropine inhibited bronchoconstriction, but methoctramine (muscarinic M2 receptor-selective) produced a dose-dependent increase in bronchoconstriction (up to 46%). Methoctramine also produced increases in bronchoconstriction induced by aerosols of histamine (up to 45%) and platelet activating factor (up to 118%), demonstrating nonspecific airway hyperresponsiveness. This effect of methoctramine was not inhibited by atropine, DAC-5945 or vagotomy and could not be attributed to altered arachidonic acid metabolism or beta-adrenergic antagonism. However, propranolol prevented methoctramine-induced airway hyperresponsiveness, suggesting that this effect resulted from the reported ganglionic blocking activity of methoctramine. In conclusion, muscarinic receptors do not appear to play an important role in antigen-induced bronchoconstriction in anesthetized guinea pigs. Furthermore, caution should be exercised in using methoctramine to characterize the roles of muscarinic receptors in airway inflammatory responses in vivo.
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Affiliation(s)
- R E Howell
- Nova Pharmaceutical Corporation, Baltimore, MD 21224
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26
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Barocelli E, Ballabeni V, Chiavarini M, Molina E, Impicciatore M. Functional comparison between nuvenzepine and pirenzepine on different guinea pig isolated smooth muscle preparations. Pharmacol Res 1994; 30:161-70. [PMID: 7816744 DOI: 10.1016/1043-6618(94)80007-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The antimuscarinic agents nuvenzepine and pirenzepine were tested on four guinea pig isolated smooth muscle preparations in order to better investigate the existence of differences in the functional activities of such antagonists, as suggested by previous reports. The effects of both compounds were compared to those of atropine. Nuvenzepine showed a four-fold higher affinity than pirenzepine in competitively antagonizing acetylcholine-induced contractions on isolated ileal musculature (pA2 = 7.08 +/- 0.15) and on longitudinal ileum dispersed cells (pA2 = 7.11 +/- 0.19). By contrast, unlike pirenzepine which was ineffective, nuvenzepine inhibited histamine-induced ileal motor activity in a dualistic manner, behaving as an irreversible competitive H1 antagonist (pA2 = 5.02 +/- 0.11). Nuvenzepine was almost equipotent to pirenzepine in competitively preventing bethanechol-induced gall-bladder contractions (pA2 = 7.23 +/- 0.16) and it displayed a four-fold higher potency than pirenzepine in blocking vagal-stimulated tracheal constrictions (pIC50 = 6.77 +/- 0.06). Both compounds were definitely less potent than atropine. On the whole, these findings indicate that, on the selected preparations, nuvenzepine substantially shares the antimuscarinic properties of pirenzepine but it is also endowed with a (weak) H1-blocking action. Furthermore, based on some observations, the presence in gallbladder smooth muscle of muscarinic receptors distinguishable from those of ileum could be speculated.
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Affiliation(s)
- E Barocelli
- Institute of Pharmacology and Pharmacognosy, University of Parma, Italy
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27
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POSTER COMMUNICATIONS. Br J Pharmacol 1994. [DOI: 10.1111/j.1476-5381.1994.tb16299.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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28
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D'Agostino G, Renzetti AR, Zonta F, Subissi A. Selectivity of LG50643 for postjunctional muscarinic-receptor subtype in the guinea-pig trachea. J Pharm Pharmacol 1994; 46:332-6. [PMID: 8083801 DOI: 10.1111/j.2042-7158.1994.tb03807.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The effects of (+/-)-LG50643, a new N-quaternary tropinic ester of phenylcyclohexene carboxylic acid, endowed with a potent antimuscarinic activity, have been investigated on muscarinic receptor-mediated responses of the guinea-pig trachea to electrical field stimulation. An isolated preparation which allows the simultaneous measurement of tritiated acetylcholine release (prejunctional effect) and smooth muscle contraction (postjunctional effect) was used. The guinea-pig epithelium-deprived trachea was stimulated with 500 pulses (20 Hz, 1 ms, 9 V for 5 s, 30 s apart) in the presence of indomethacin (1 microM). Three successive pre- and postjunctional responses were observed. The potencies (-logEC50) of (+/-)-LG50643 for pre- and postjunctional muscarinic receptors were determined and compared with those of selective muscarinic antagonists. In addition, the affinity values of (+/-)-LG50643 for muscarinic-receptor subtypes were determined in radioligand binding experiments in cerebral cortex, heart and salivary glands of rat as target tissues for M1, M2 and M3 receptors, respectively. The results obtained in both functional and binding assays indicate (+/-)-LG50643 is a potent and selective antagonist for the M3-receptor subtype.
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29
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Watson CD, Hewitt MJ, Fone KC, Dickinson SL, Bennett GW. Behavioural effects of scopolamine and the TRH analogue RX77368 on radial arm maze performance in the rat. J Psychopharmacol 1994; 8:88-93. [PMID: 22298534 DOI: 10.1177/026988119400800203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Effects of repeated intracerebroventricular administration of the thyrotrophin-releasing hormone (TRH) analogue, RX77368 (3,3'-dimethyl-TRH, 2 μg, once daily), on a scopolamine-induced performance deficit in an eight-arm radial maze were evaluated in adult rats. Scopolamine (0.3 mg/kg i.p.-30 min) pre-treatment produced a significant deficit in the number of unrepeated arm entries and total arm entries and increased the percentage of incorrect arm entries and the total time on the maze, compared with saline-treated controls. Prior treatment with RX77368 (40 min before maze testing) produced a partial but significant attenuation of the scopolamine-induced performance deficit on the maze during the first five trials but RX77368 also enhanced maze performance during the same period when given alone. These results suggest that the observed scopolamine-induced performance deficit on the radial arm maze partly results from a reduction in locomotion and maze exploration rather than solely impairment of memory, and that RX77368 treatment may improve radial maze performance by increasing arousal and exploratory behaviour in rats rather than directly enhancing cognition.
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Affiliation(s)
- C D Watson
- Department of Physiology and Pharmacology, Medical School, Queen's Medical Centre, Nottingham University, Nottingham NG7 2UH
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30
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POSTER COMMUNICATIONS. Br J Pharmacol 1993. [DOI: 10.1111/j.1476-5381.1993.tb16290.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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31
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Racké K, Brunn G, Elsner M, Wessler I. Effects of indomethacin on muscarinic inhibition of endogenous noradrenaline release from rat isolated trachea. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 1993; 348:21-7. [PMID: 8377837 DOI: 10.1007/bf00168532] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The release of endogenous noradrenaline from rat isolated tracheae was evoked by electrical field stimulation (3 Hz, 540 pulses) in the presence of yohimbine, desipramine and tyrosine. The muscarine receptor agonist oxotremorine concentration-dependently inhibited the evoked release of noradrenaline by 95% at 1 mumol/l, EC50 values in two series of experiments 41 and 57 nmol/l, respectively. The effect of oxotremorine was antagonized by the non-selective muscarine receptor antagonist scopolamine (10-1000 nmol/l) in a manner suggesting a simple competitive interaction (slope of Schild plot -0.94; pA2 value 8.88). However, the M2 selective muscarine receptor antagonist methoctramine (0.1-10 mumol/l) affected the action of oxotremorine in a manner suggesting a complex interaction (slope of Schild plot -0.47). Addition of indomethacin (3 mumol/l) caused an increase of the evoked release of noradrenaline by 45% and low concentrations of oxotremorine (0.01 and 0.1 mumol/l, but not 1 mumol/l) became less effective resulting in a slight shift to the right of the concentration response curve (EC50 169 nmol/l). Moreover, in the presence of indomethacin methoctramine (0.1-10 mumol/l) antagonized the effects of oxotremorine in a manner suggesting a simple competitive interaction (slope of Schild plot -0.93, pA2 value 7.61). In the presence of indomethacin, the concentration response curve of oxotremorine was only slightly shifted to the right in the presence of the M1 receptor selective antagonist pirenzepine (1 mumol/l, -log KB 6.1) and not significantly affected by the M3 receptor selective antagonist p-fluoro-hexahydrosiladifenidol (1 mumol/l). In conclusion, the release of noradrenaline in the rat trachea is inhibited via presynaptic muscarine heteroreceptors of the M2 subtype.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- K Racké
- Department of Pharmacology, University of Frankfurt, Germany
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Abstract
Sensory afferent nerves relay impulses from the airways to the central nervous system so that appropriate changes in bronchomotor tone and breathing patterns may occur. The dominant efferent control of airways smooth muscle is exerted via bronchoconstrictor parasympathetic cholinergic nerves. In some species this is opposed by bronchodilator sympathetic noradrenergic nerves. In addition, there exist both excitatory bronchoconstrictor and inhibitory bronchodilator non-adrenergic, non-cholinergic pathways. This review examines the role of the different branches of the autonomic nervous system in the control of airways smooth muscle tone with particular reference to modulation of these branches and the interactions which may exist between them.
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Affiliation(s)
- Y D Pendry
- Department of Cardiovascular and Respiratory Pharmacology, Glaxo Group Research, Ware, Hertfordshire, U.K
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Abstract
Muscarinic receptor subtypes in the airways appear to subserve different physiological functions. M1-receptors facilitate neurotransmission through parasympathetic ganglia and enhance cholinergic reflexes, but are also localized to alveolar walls. M2-receptors act as autoreceptors on post-ganglionic cholinergic nerves and inhibit acetylcholine release. There is some evidence that they may be defective in asthma (as a consequence of airway inflammation?) and this may enhance cholinergic reflexes and account for beta-blocker-induced asthma. M2-receptors in airway smooth muscle may also counteract the bronchodilator action of beta-agonists. M3-receptors mediate contractile responses in airway smooth muscle via phosphoinositide hydrolysis, and are the predominant receptors on submucosal glands and airway vascular endothelium. M4- and M5-receptors have not been identified in human airways, but in rabbit lung M4-receptors are expressed on alveolar walls and smooth muscle. Anticholinergic drugs which selectively block M3 and M1-receptors may have an advantage over currently used non-selective antagonists in the treatment of airway obstruction.
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Affiliation(s)
- P J Barnes
- National Heart & Lung Institute, London, UK
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Kilbinger H, Dietrich C, von Bardeleben RS. Functional relevance of presynaptic muscarinic autoreceptors. JOURNAL OF PHYSIOLOGY, PARIS 1993; 87:77-81. [PMID: 8305900 DOI: 10.1016/0928-4257(93)90001-a] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Pre- and postsynaptic muscarinic receptors have been characterized in the isolated trachea and ileal circular muscle of the guinea pig. The muscarinic autoreceptors mediating inhibition of acetylcholine release in the circular muscle belong to the M1 subtype, whereas those inhibiting acetylcholine release in the trachea are M2 or M4 receptors. In both tissues the postsynaptic muscarinic receptors are M3 receptors. Blockade of the autoreceptors by selective M1 and M2/M4 receptor antagonists leads to facilitation of cholinergic neurotransmission.
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Affiliation(s)
- H Kilbinger
- Department of Pharmacology, University of Mainz, Germany
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