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Kang H, Kim J, Park CH, Jeong B, So I. Direct modulation of TRPC ion channels by Gα proteins. Front Physiol 2024; 15:1362987. [PMID: 38384797 PMCID: PMC10880550 DOI: 10.3389/fphys.2024.1362987] [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: 12/29/2023] [Accepted: 01/26/2024] [Indexed: 02/23/2024] Open
Abstract
GPCR-Gi protein pathways are involved in the regulation of vagus muscarinic pathway under physiological conditions and are closely associated with the regulation of internal visceral organs. The muscarinic receptor-operated cationic channel is important in GPCR-Gi protein signal transduction as it decreases heart rate and increases GI rhythm frequency. In the SA node of the heart, acetylcholine binds to the M2 receptor and the released Gβγ activates GIRK (I(K,ACh)) channel, inducing a negative chronotropic action. In gastric smooth muscle, there are two muscarinic acetylcholine receptor (mAChR) subtypes, M2 and M3. M2 receptor activates the muscarinic receptor-operated nonselective cationic current (mIcat, NSCC(ACh)) and induces positive chronotropic effect. Meanwhile, M3 receptor induces hydrolysis of PIP2 and releases DAG and IP3. This IP3 increases intracellular Ca2+ and then leads to contraction of GI smooth muscles. The activation of mIcat is inhibited by anti-Gi/o protein antibodies in GI smooth muscle, indicating the involvement of Gαi/o protein in the activation of mIcat. TRPC4 channel is a molecular candidate for mIcat and can be directly activated by constitutively active Gαi QL proteins. TRPC4 and TRPC5 belong to the same subfamily and both are activated by Gi/o proteins. Initial studies suggested that the binding sites for G protein exist at the rib helix or the CIRB domain of TRPC4/5 channels. However, recent cryo-EM structure showed that IYY58-60 amino acids at ARD of TRPC5 binds with Gi3 protein. Considering the expression of TRPC4/5 in the brain, the direct G protein activation on TRPC4/5 is important in terms of neurophysiology. TRPC4/5 channels are also suggested as a coincidence detector for Gi and Gq pathway as Gq pathway increases intracellular Ca2+ and the increased Ca2+ facilitates the activation of TRPC4/5 channels. More complicated situation would occur when GIRK, KCNQ2/3 (IM) and TRPC4/5 channels are co-activated by stimulation of muscarinic receptors at the acetylcholine-releasing nerve terminals. This review highlights the effects of GPCR-Gi protein pathway, including dopamine, μ-opioid, serotonin, glutamate, GABA, on various oragns, and it emphasizes the importance of considering TRPC4/5 channels as crucial players in the field of neuroscience.
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Affiliation(s)
- Hana Kang
- Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Jinhyeong Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Christine Haewon Park
- Department of Physiology, University of California, San Francisco, San Francisco, CA, United States
| | - Byeongseok Jeong
- Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Insuk So
- Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea
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2
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Schoeller C, Hoffmann S, Adolph S, Regenthal R, Abraham G. Expression of muscarinic acetylcholine receptors in turkey cardiac chambers. Res Vet Sci 2021; 136:602-608. [PMID: 33895569 DOI: 10.1016/j.rvsc.2021.04.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 04/12/2021] [Accepted: 04/13/2021] [Indexed: 10/21/2022]
Abstract
The aim of the present study was to characterize the specific binding sites for [N-methyl-3H]-scopolamine ([3H]-NMS), a radioligand for labeling muscarinic acetylcholine receptors (mAChRs), in membranes of four heart chambers obtained from adult male British United Turkey (BUT) Big 6 ("meat-type") and Cröllwitzer ("wild-type") turkeys. MAChR subtypes were examined by inhibiting [3H]-NMS binding with subtype selective non-labelled receptor antagonists. In all left and right atria as well as left and right ventricles of both turkey breeds, the specific [3H]-NMS binding was saturable, reversible and of high affinity (KD range: 0.5-1.0 nM). The maximum receptor density (Bmax) was not significantly different between the four cardiac chambers of BUT Big 6 turkeys, but a significant difference was found between atria and ventricles of Cröllwitzer turkeys. Moreover, significant lower Bmax was found in the atria of Cröllwitzer turkeys than in the atria of BUT Big 6, while the ventricular Bmax was significantly higher. In all cardiac chambers, unlabeled mAChR antagonists competed for specific [3H]-NMS binding sites in a concentration-dependent manner, suggesting the presence of the M3 and M2 receptor subtypes, whereby the latter was the predominant subtype. The presence of the M1 subtype could not be excluded. In conclusion, there was a difference between BUT Big 6 ("meat-type") and Cröllwitzer ("wild-type") turkeys with regard to receptor density in heart chambers with dominant M2 and M3 receptor subtypes.
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Affiliation(s)
- Caroline Schoeller
- Institute of Pharmacology, Pharmacy and Toxicology, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 15, D-04103 Leipzig, Germany
| | - Sandra Hoffmann
- Institute of Pharmacology, Pharmacy and Toxicology, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 15, D-04103 Leipzig, Germany
| | - Stephanie Adolph
- Institute of Pharmacology, Pharmacy and Toxicology, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 15, D-04103 Leipzig, Germany
| | - Ralf Regenthal
- Rudolf-Boehm-Institute of Pharmacology and Toxicology, Clinical Pharmacology, Faculty of Medicine, University of Leipzig, Härtelstr. 16 -18, D-04107 Leipzig, Germany.
| | - Getu Abraham
- Institute of Pharmacology, Pharmacy and Toxicology, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 15, D-04103 Leipzig, Germany.
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3
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Zhao L, Chen T, Hang P, Li W, Guo J, Pan Y, Du J, Zheng Y, Du Z. Choline Attenuates Cardiac Fibrosis by Inhibiting p38MAPK Signaling Possibly by Acting on M 3 Muscarinic Acetylcholine Receptor. Front Pharmacol 2019; 10:1386. [PMID: 31849653 PMCID: PMC6900736 DOI: 10.3389/fphar.2019.01386] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 10/31/2019] [Indexed: 01/08/2023] Open
Abstract
Choline has been reported to produce a variety of cellular functions including cardioprotection via activating M3 muscarinic acetylcholine receptor (M3R) under various insults. However, whether choline offers similar beneficial effects via the same mechanism in cardiac fibrosis remained unexplored. The present study aimed to investigate the effects of choline on cardiac fibrosis and the underlying signaling mechanisms, particularly the possible involvement of M3R. Transverse aortic constriction (TAC) mouse model was established to simulate the cardiac fibrosis. Transforming growth factor (TGF)-β1 treatment was employed to induce proliferation of cardiac fibroblasts in vitro. Choline chloride and M3R antagonist 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP) were used to unravel the potential role of M3R. Cardiac function was assessed by echocardiography and interstitial fibrosis was quantified by Masson staining. Protein levels of collagens I and III were determined by Western blot analysis. The role of M3R in the proliferation cardiac fibroblasts was validated by silencing M3R with specific small interference RNA (siRNA). Furthermore, the mitogen-activated protein kinase (MAPK) signaling pathway including p38MAPK and ERK1/2 as well as the TGF-β1/Smad pathway were analyzed. M3R protein was found abundantly in cardiac fibroblasts. M3R protein level, as identified by Western blotting, was higher in mice with excessive cardiac fibrosis and in TGF-β1-induced cardiac fibrosis as well. Choline significantly inhibited interstitial fibrosis, and this beneficial action was reversed by 4-DAMP. Production of collagens I and III was reduced after choline treatment but restored by 4-DAMP. Expression silence of endogenous M3R using siRNA increased the level of collagen I. Furthermore, the TGF-β1/Smad2/3 and the p38MAPK pathways were both suppressed by choline. In summary, choline produced an anti-fibrotic effect both in vivo and in vitro by regulating the TGF-β1/Smad2/3 and p38MAPK pathways. These findings unraveled a novel pharmacological property of choline linked to M3R, suggesting that choline regulates cardiac fibrosis and the associated heart diseases possibly by acting on M3R.
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Affiliation(s)
- Lihui Zhao
- Institute of Clinical Pharmacology, the Second Affiliated Hospital of Harbin Medical University (The University Key Laboratory of Drug Research, Heilongjiang Province), Harbin, China.,Department of Clinical Pharmacology, College of Pharmacy, Harbin Medical University, Harbin, China
| | - Tingting Chen
- Institute of Clinical Pharmacology, the Second Affiliated Hospital of Harbin Medical University (The University Key Laboratory of Drug Research, Heilongjiang Province), Harbin, China.,Department of Clinical Pharmacology, College of Pharmacy, Harbin Medical University, Harbin, China
| | - Pengzhou Hang
- Institute of Clinical Pharmacology, the Second Affiliated Hospital of Harbin Medical University (The University Key Laboratory of Drug Research, Heilongjiang Province), Harbin, China.,Department of Clinical Pharmacology, College of Pharmacy, Harbin Medical University, Harbin, China
| | - Wen Li
- Institute of Clinical Pharmacology, the Second Affiliated Hospital of Harbin Medical University (The University Key Laboratory of Drug Research, Heilongjiang Province), Harbin, China.,Department of Clinical Pharmacology, College of Pharmacy, Harbin Medical University, Harbin, China
| | - Jing Guo
- Institute of Clinical Pharmacology, the Second Affiliated Hospital of Harbin Medical University (The University Key Laboratory of Drug Research, Heilongjiang Province), Harbin, China.,Department of Clinical Pharmacology, College of Pharmacy, Harbin Medical University, Harbin, China
| | - Yang Pan
- Institute of Clinical Pharmacology, the Second Affiliated Hospital of Harbin Medical University (The University Key Laboratory of Drug Research, Heilongjiang Province), Harbin, China.,Department of Clinical Pharmacology, College of Pharmacy, Harbin Medical University, Harbin, China
| | - Jingjing Du
- Institute of Clinical Pharmacology, the Second Affiliated Hospital of Harbin Medical University (The University Key Laboratory of Drug Research, Heilongjiang Province), Harbin, China.,Department of Clinical Pharmacology, College of Pharmacy, Harbin Medical University, Harbin, China
| | - Yuyang Zheng
- Institute of Clinical Pharmacology, the Second Affiliated Hospital of Harbin Medical University (The University Key Laboratory of Drug Research, Heilongjiang Province), Harbin, China.,Department of Clinical Pharmacology, College of Pharmacy, Harbin Medical University, Harbin, China
| | - Zhimin Du
- Institute of Clinical Pharmacology, the Second Affiliated Hospital of Harbin Medical University (The University Key Laboratory of Drug Research, Heilongjiang Province), Harbin, China.,Department of Clinical Pharmacology, College of Pharmacy, Harbin Medical University, Harbin, China.,State Key Laboratory of Quality Research in Chinese Medicines, Macau University of Science and Technology, Macau, China
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4
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Heijman J, Kirchner D, Kunze F, Chrétien EM, Michel-Reher MB, Voigt N, Knaut M, Michel MC, Ravens U, Dobrev D. Muscarinic type-1 receptors contribute to I K,ACh in human atrial cardiomyocytes and are upregulated in patients with chronic atrial fibrillation. Int J Cardiol 2017; 255:61-68. [PMID: 29290419 DOI: 10.1016/j.ijcard.2017.12.050] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 12/13/2017] [Accepted: 12/19/2017] [Indexed: 01/06/2023]
Abstract
BACKGROUND Basal and acetylcholine-gated inward-rectifier K+-currents (IK1 and IK,ACh, respectively) are altered in atrial fibrillation (AF). Gi-protein-coupled muscarinic (M) receptors type-2 are considered the predominant receptors activating IK,ACh. Although a role for Gq-coupled non-M2-receptor subtypes has been suggested, the precise regulation of IK,ACh by multiple M-receptor subtypes in the human atrium is unknown. Here, we investigated M1-receptor-mediated IK,ACh regulation and its remodeling in chronic AF (cAF). METHODS AND RESULTS M1-receptor mRNA and protein abundance were increased in atrial cardiomyocyte fractions and atrial homogenates from cAF patients, whereas M2-receptor levels were unchanged. The regulation of IK,ACh by M1-receptors was investigated in right-atrial cardiomyocytes using two applications of the M-receptor agonist carbachol (CCh, 2μM), with pharmacological interventions during the second application. CCh application produced a rapid current increase (Peak-IK,ACh), which declined to a quasi-steady-state level (Qss-IK,ACh). In sinus rhythm (Ctl) the selective M1-receptor antagonists pirenzepine (10nM) and muscarinic toxin-7 (MT-7, 10nM) significantly inhibited CCh-activated Peak-IK,ACh, whereas in cAF they significantly reduced both Peak- and Qss-IK,ACh, with no effects on basal inward-rectifier currents in either group. Conversely, the selective M1-receptor agonist McN-A-343 (100μM) induced a current similar to the CCh-activated current in Ctl atrial cardiomyocytes pretreated with pertussis toxin to inhibit M2-receptor-mediated Gi-protein signaling, which was abolished by MT-7. Computational modeling indicated that M1- and M2-receptors redundantly activate IK,ACh to abbreviate APD, albeit with predominant effects of M2-receptors. CONCLUSION Our data suggest that Gq-coupled M1-receptors also regulate human atrial IK,ACh and that their relative contribution to IK,ACh activation is increased in cAF patients. We provide novel insights about the role of non-M2-receptors in human atrial cardiomyocytes, which may have important implications for understanding AF pathophysiology.
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Affiliation(s)
- Jordi Heijman
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany; Department of Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
| | - Dorit Kirchner
- Department of Pharmacology and Toxicology, Carl Gustav Carus Medical Faculty, Dresden University of Technology, Dresden, Germany
| | - Franziska Kunze
- Department of Pharmacology and Toxicology, Carl Gustav Carus Medical Faculty, Dresden University of Technology, Dresden, Germany
| | - Eva Maria Chrétien
- Department of Pharmacology and Toxicology, Carl Gustav Carus Medical Faculty, Dresden University of Technology, Dresden, Germany
| | | | - Niels Voigt
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
| | - Michael Knaut
- Heart Surgery, Heart Center Dresden, Carl Gustav Carus Medical Faculty, Dresden University of Technology, Dresden, Germany
| | - Martin C Michel
- Department of Pharmacology, Johannes Gutenberg University, Mainz, Germany
| | - Ursula Ravens
- Department of Pharmacology and Toxicology, Carl Gustav Carus Medical Faculty, Dresden University of Technology, Dresden, Germany; Institute of Experimental Cardiovascular Medicine, University Heart Center Freiburg-Bad Krozingen, Freiburg, Germany
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany; Department of Pharmacology and Toxicology, Carl Gustav Carus Medical Faculty, Dresden University of Technology, Dresden, Germany.
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5
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Abraham G. The importance of muscarinic receptors in domestic animal diseases and therapy: Current and future perspectives. Vet J 2016; 208:13-21. [DOI: 10.1016/j.tvjl.2015.10.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 10/06/2015] [Accepted: 10/08/2015] [Indexed: 01/24/2023]
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6
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Mahati E, Li P, Kurata Y, Maharani N, Ikeda N, Sakata S, Ogura K, Miake J, Aiba T, Shimizu W, Nakasone N, Ninomiya H, Higaki K, Yamamoto K, Nakai A, Shirayoshi Y, Hisatome I. M3 Muscarinic Receptor Signaling Stabilizes a Novel Mutant Human Ether-a-Go-Go-Related Gene Channel Protein via Phosphorylation of Heat Shock Factor 1 in Transfected Cells. Circ J 2016; 80:2443-2452. [PMID: 27803431 DOI: 10.1253/circj.cj-16-0712] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Endang Mahati
- Division of Regenerative Medicine and Therapeutics, Department of Genetic Medicine and Regenerative Therapeutics, Institute of Regenerative Medicine and Biofunction, Tottori University Graduate School of Medical Science
- Department of Pharmacology and Therapeutics, Faculty of Medicine, Diponegoro University
| | - Peili Li
- Division of Regenerative Medicine and Therapeutics, Department of Genetic Medicine and Regenerative Therapeutics, Institute of Regenerative Medicine and Biofunction, Tottori University Graduate School of Medical Science
| | | | - Nani Maharani
- Division of Regenerative Medicine and Therapeutics, Department of Genetic Medicine and Regenerative Therapeutics, Institute of Regenerative Medicine and Biofunction, Tottori University Graduate School of Medical Science
- Department of Pharmacology and Therapeutics, Faculty of Medicine, Diponegoro University
- Center for Biomedical Research (CEBIOR), Faculty of Medicine, Diponegoro University
| | - Nobuhito Ikeda
- Division of Regenerative Medicine and Therapeutics, Department of Genetic Medicine and Regenerative Therapeutics, Institute of Regenerative Medicine and Biofunction, Tottori University Graduate School of Medical Science
| | - Shinji Sakata
- Department of Pediatrics, Faculty of Medicine, Tottori University
| | - Kazuyoshi Ogura
- Division of Cardiovascular Medicine, Department of Molecular Medicine and Therapeutics, Faculty of Medicine, Tottori University
| | - Junichiro Miake
- Division of Cardiovascular Medicine, Department of Molecular Medicine and Therapeutics, Faculty of Medicine, Tottori University
| | - Takeshi Aiba
- Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center
| | - Wataru Shimizu
- Division of Cardiology and Regenerative Medicine, Nippon Medical School
| | - Naoe Nakasone
- Department of Biological Regulation, Faculty of Medicine, Tottori University
| | - Haruaki Ninomiya
- Department of Biological Regulation, Faculty of Medicine, Tottori University
| | - Katsumi Higaki
- Division of Functional Genomics, Research Center for Bioscience and Technology, Tottori University
| | - Kazuhiro Yamamoto
- Division of Cardiovascular Medicine, Department of Molecular Medicine and Therapeutics, Faculty of Medicine, Tottori University
| | - Akira Nakai
- Department of Biochemistry and Molecular Biology, Yamaguchi University School of Medicine
| | - Yasuaki Shirayoshi
- Division of Regenerative Medicine and Therapeutics, Department of Genetic Medicine and Regenerative Therapeutics, Institute of Regenerative Medicine and Biofunction, Tottori University Graduate School of Medical Science
| | - Ichiro Hisatome
- Division of Regenerative Medicine and Therapeutics, Department of Genetic Medicine and Regenerative Therapeutics, Institute of Regenerative Medicine and Biofunction, Tottori University Graduate School of Medical Science
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M3-mAChR Stimulation Exerts Anti-apoptotic Effect Via Activating the HIF-1α/HO-1/VEGF Signaling Pathway in H9c2 Rat Ventricular Cells. J Cardiovasc Pharmacol 2012; 60:474-82. [DOI: 10.1097/fjc.0b013e31826c1c13] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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8
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Benes J, Varejkova E, Farar V, Novakova M, Myslivecek J. Decrease in heart adrenoceptor gene expression and receptor number as compensatory tool for preserved heart function and biological rhythm in M(2) KO animals. Naunyn Schmiedebergs Arch Pharmacol 2012; 385:1161-73. [PMID: 23093370 DOI: 10.1007/s00210-012-0800-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Accepted: 10/05/2012] [Indexed: 11/26/2022]
Abstract
Muscarinic receptors (MR) are main cardioinhibitory receptors. We investigated the changes in gene expression, receptor number, echocardiography, muscarinic/adrenergic agonist/antagonist changes in heart rate (HR) and HR biorhythm in M(2) KO mice (mice lacking the main cardioinhibitory receptors) in the left ventricle (LV) and right ventricle (RV). We hypothesize that the disruption of M(2) MR, key players in parasympathetic bradycardia, would change the number of receptors with antagonistic effects on the heart (β(1)- and β(2)-adrenoceptors, BAR), while the function of the heart would be changed only marginally. We have found changes in LV, but not in RV: decrease in M(3) MR, β(1)- and β(2)-adrenoceptor gene expressions that were accompanied by a decrease in MR and BAR receptor binding. No changes were found both in LV systolic and diastolic function as assessed by echocardiography (e.g., similar LV end-systolic and end-diastolic diameter, fractional shortening, mitral flow characteristics, and maximal velocity in LV outflow tract). We have found only marginal changes in specific HR biorhythm parameters. The effects of isoprenaline and propranolol on HR were similar in WT and KO (but with lesser extent). Atropine was not able to increase HR in KO animals. Carbachol decreased the HR in WT but increased HR in KO, suggesting the presence of cardiostimulatory MR. Therefore, we can conclude that although the main cardioinhibitory receptors are not present in the heart, the function is not much affected. As possible mechanisms of almost normal cardiac function, the decreases of both β(1)- and β(2)-adrenoceptor gene expression and receptor binding should be considered.
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Affiliation(s)
- Jan Benes
- Institute of Physiology, 1st Faculty of Medicine, Charles University, Albertov 5, 128 00, Prague, Czech Republic
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9
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Harada N, Ochi K, Yaosaka N, Teraoka H, Hiraga T, Iwanaga T, Unno T, Komori S, Yamada M, Kitazawa T. Immunohistochemical and functional studies for M3muscarinic receptors and cyclo-oxygenase-2 expressed in the mouse atrium. ACTA ACUST UNITED AC 2012; 32:41-52. [DOI: 10.1111/j.1474-8673.2012.00472.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 03/08/2012] [Accepted: 04/15/2012] [Indexed: 11/30/2022]
Affiliation(s)
- N. Harada
- Department of Veterinary Medicine; Rakuno Gakuen University; Ebetsu; Hokkaido; 069-8501; Japan
| | - K. Ochi
- Department of Veterinary Medicine; Rakuno Gakuen University; Ebetsu; Hokkaido; 069-8501; Japan
| | - N. Yaosaka
- Department of Veterinary Science; Rakuno Gakuen University; Ebetsu; Hokkaido; 069-8501; Japan
| | - H. Teraoka
- Department of Veterinary Medicine; Rakuno Gakuen University; Ebetsu; Hokkaido; 069-8501; Japan
| | - T. Hiraga
- Department of Veterinary Medicine; Rakuno Gakuen University; Ebetsu; Hokkaido; 069-8501; Japan
| | - T. Iwanaga
- Department of Functional Morphology, Laboratory of Histology and Cytology; Hokkaido University Graduate School of Medicine; Sapporo; 060-8638; Japan
| | - T. Unno
- Laboratory of Pharmacology, Faculty of Applied Biological Science; Gifu University; Gifu; 501-1193; Japan
| | - S. Komori
- Laboratory of Pharmacology, Faculty of Applied Biological Science; Gifu University; Gifu; 501-1193; Japan
| | - M. Yamada
- Common Resources Group; Okinawa Institute of Science and Technology; Okinawa; 904-0411; Japan
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10
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Andersson KE, Campeau L, Olshansky B. Cardiac effects of muscarinic receptor antagonists used for voiding dysfunction. Br J Clin Pharmacol 2012; 72:186-96. [PMID: 21595741 DOI: 10.1111/j.1365-2125.2010.03813.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Antimuscarinic agents are the main drugs used to treat patients with the overactive bladder (OAB) syndrome, defined as urgency, with or without urgency incontinence, usually with increased daytime frequency and nocturia. Since the treatment is not curative and since OAB is a chronic disease, treatment may be life-long. Antimuscarinics are generally considered to be ‘safe’ drugs, but among the more serious concerns related to their use is the risk of cardiac adverse effects, particularly increases in heart rate (HR) and QT prolongation and induction of polymorphic ventricular tachycardia (torsade de pointes). An elevated resting HR has been linked to overall increased morbidity and mortality, particularly in patients with cardiovascular diseases. QT prolongation and its consequences are not related to blockade of muscarinic receptors, but rather linked to inhibition of the hERG potassium channel in the heart. However, experience with terodiline, an antimuscarinic drug causing torsade de pointes in patients, has placed the whole drug class under scrutiny. The potential of the different antimuscarinic agents to increase HR and/or prolong the QT time has not been extensively explored for all agents in clinical use. Differences between drugs cannot be excluded, but risk assessments based on available evidence are not possible.
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Affiliation(s)
- Karl-Erik Andersson
- Wake Forest Institute for Regenerative Medicine,Wake Forest University School of Medicine, Medical Center Boulevard, Winston Salem, NC 27157, USA.
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11
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Liu Y, Sun L, Pan Z, Bai Y, Wang N, Zhao J, Xu C, Li Z, Li B, Du Z, Lu Y, Gao X, Yang B. Overexpression of M₃ muscarinic receptor is a novel strategy for preventing sudden cardiac death in transgenic mice. Mol Med 2011; 17:1179-87. [PMID: 21785809 DOI: 10.2119/molmed.2011.00093] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Accepted: 07/13/2011] [Indexed: 11/06/2022] Open
Abstract
The present study was designed to investigate the cardiac benefits of M₃ muscarinic receptor (M₃-mAChR) overexpression and whether these effects are related to the regulation of the inward rectifying K⁺ channel by microRNA-1 (miR-1) in a conditional overexpression mouse model. A cardiac-specific M₃-mAChR transgenic mouse model was successfully established for the first time in this study using microinjection, and the overexpression was confirmed by both reverse transcriptase-polymerase chain reaction and Western blot techniques. We demonstrated that M₃-mAChR overexpression dramatically reduced the incidence of arrhythmias and decreased the mortality in a mouse model of myocardial ischemia-reperfusion (I/R). By using whole-cell patch techniques, M₃-mAChR overexpression significantly shortened the action potential duration and restored the membrane repolarization by increasing the inward rectifying K⁺ current. By using Western blot techniques, M₃-mAChR overexpression also rescued the expression of the inward rectifying K⁺ channel subunit Kir2.1 after myocardial I/R injury. This result was accompanied by suppression of upregulation miR-1. We conclude that M₃-mAChR overexpression reduced the incidence of arrhythmias and mortality after myocardial I/R by protecting the myocardium from ischemia in mice. This effect may be mediated by increasing the inward rectifying K⁺ current by downregulation of arrhythmogenic miR-1 expression, which might partially be a novel strategy for antiarrhythmias, leading to sudden cardiac death.
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Affiliation(s)
- Yan Liu
- Department of Pharmacology, State-Province Key Laboratories of Biomedicine and Pharmaceutics, Harbin, Heilongjiang, China
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12
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López JR, Espinosa R, Landazuru P, Linares N, Allen P, Mijares A. [Dysfunction of diastolic [Ca²⁺] in cardiomyocytes isolated from chagasic patients]. Rev Esp Cardiol 2011; 64:456-62. [PMID: 21511385 DOI: 10.1016/j.recesp.2011.01.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Accepted: 01/21/2011] [Indexed: 11/15/2022]
Abstract
INTRODUCTION AND OBJECTIVES Chagas is an endemic disease in Latin America, caused by the parasite Trypanosoma cruzi, which usually affects the functioning of the heart. We have studied the regulation of intracellular calcium in cardiomyocytes isolated from chagasic patients with different degrees of heart dysfunction. METHODS Calcium selective microelectrodes were used to simultaneously measure diastolic calcium concentration ([Ca²⁺](d)) and resting membrane potential in endomyocardial biopsies obtained from chagasic patients and controls. RESULTS The [Ca²⁺](d) increased by 123%, 295%, and 738% in chagasic patients in functional class I, II, and III, respectively, in relation to controls. Membrane potential showed a partial depolarization of 6% in functional class I, 10% in functional class II, and 22% in functional class III, compared to control values. Alteration in the [Ca²⁺](d) was partially reverted by 1-[6-[[(17ß)-3-metoxyestra-1,3,5(10)-trien-17-yl]amino]hexyl]-1H-pyrrole-2,5-dione (U-73122), a β-phospholipase C antagonist, and by 2-aminoethoxydiphenyl-borate (2-APB), an inositol 1,4,5-trisphosphate receptor blocker. Phenylephrine, an agent that induces a rapid transient increase in 1,4,5-trisphosphate intracellular content, produced a rise in [Ca²⁺](d), higher in chagasic cardiomyocytes than in controls, and its effect was fully inhibited by 2-APB. CONCLUSIONS In cardiomyocytes from chagasic patients there is a dysfunction of the regulation of the [Ca²⁺](d), which correlates with the cardiac abnormalities observed in the different stages of the disease. This disturbance in the regulation of intracellular calcium appears to be associated with alterations in the regulation of intracellular messenger inositol 1,4,5-trisphosphate.
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Affiliation(s)
- José R López
- Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela
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Constitutive overexpression of muscarinic receptors leads to vagal hyperreactivity. PLoS One 2010; 5:e15618. [PMID: 21203511 PMCID: PMC3008725 DOI: 10.1371/journal.pone.0015618] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Accepted: 11/15/2010] [Indexed: 01/10/2023] Open
Abstract
Background Alterations in muscarinic receptor expression and acetylcholinesterase (AchE) activity have been observed in tissues from Sudden Infant Death Syndrome (SIDS). Vagal overactivity has been proposed as a possible cause of SIDS as well as of vasovagal syncopes. The aim of the present study was to seek whether muscarinic receptor overexpression may be the underlying mechanism of vagal hyperreactivity. Rabbits with marked vagal pauses following injection of phenylephrine were selected and crossed to obtain a vagal hyperreactive strain. The density of cardiac muscarinic receptors and acetylcholinesterase (AchE) gene expression were assessed. Blood markers of the observed cardiac abnormalities were also sought. Methodology/Principal Findings Cardiac muscarinic M2 and M3 receptors were overexpressed in hyperreactive rabbits compared to control animals (2.3-fold and 2.5-fold, respectively) and the severity of the phenylephrine-induced bradycardia was correlated with their densities. A similar overexpression of M2 receptors was observed in peripheral mononuclear white blood cells, suggesting that cardiac M2 receptor expression can be inferred with high confidence from measurements in blood cells. Sequencing of the coding fragment of the M2 receptor gene revealed a single nucleotide mutation in 83% of hyperreactive animals, possibly contributing for the transcript overexpression. Significant increases in AchE expression and activity were also assessed (AchE mRNA amplification ratio of 3.6 versus normal rabbits). This phenomenon might represent a compensatory consequence of muscarinic receptors overexpression. Alterations in M2 receptor and AchE expression occurred between the 5th and the 7th week of age, a critical period also characterized by a higher mortality rate of hyperreactive rabbits (52% in H rabbits versus 13% in normal rabbits) and preceeded the appearance of functional disorders. Conclusions/Significance The results suggest that cardiac muscarinic receptor overexpression plays a critical role in the development of vagal hyperreactivity, whereas AchE hyperactivity appears as a compensatory consequence of it. Since similar vagal disorders were observed recently by us in SIDS, muscarinic receptor overexpression could become a marker of risk of vasovagal syncopes and SIDS.
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Radenkovic M, Ivetic V, Popovic M, Brankovic S, Gvozdenovic L. Effects of Mistletoe (Viscum AlbumL., Loranthaceae) Extracts on Arterial Blood Pressure in Rats Treated with Atropine Sulfate and Hexocycline. Clin Exp Hypertens 2009; 31:11-9. [DOI: 10.1080/10641960802409820] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Abstract
OBJECTIVE To review darifenacin, a new anticholinergic for overactive bladder, approved in December 2004 by the U.S. Food and Drug Administration. DATA SOURCE A MEDLINE/PUBMED search was conducted to identify pertinent studies in the English language. In addition, proceedings of meetings of the International Continence Society, European Association of Urology, American Urological Association, and American College of Obstetrics and Gynecology were reviewed for relevant abstracts. Additional references were obtained from the bibliographies of these sources. Data over the time period of 1986 through September 2004 were reviewed. STUDY SELECTION All studies evaluating any aspect of darifenacin in vitro or in vivo in animals or humans. DATA SYNTHESIS Preclinical studies demonstrated that darifenacin was an antagonist at muscarinic cholinergic M1, M3, and M5 receptors. On the basis of preclinical data, darifenacin was felt to be a "uroselective" antimuscarinic. Darifenacin is extensively metabolized, with urinary excretion of parent compound being less than 10%. Darifenacin, dosed as 7.5 or 15 mg once daily, is significantly superior to placebo in reducing the numbers of micturitions, urges, incontinence episodes, and urge severity and increasing the warning time and volume per micturition. No active-controlled trial data are available. The most problematic adverse effects of darifenacin are the anticholinergic effects of dry mouth and constipation. CONCLUSION Although promising in preclinical studies, the "uroselectivity" of the anticholinergic activity of darifenacin has not been confirmed in clinical trials. No comparative data with marketed (for overactive bladder) anticholinergics are available. On the basis of available data, darifenacin does not appear to be a substantial advance upon existing anticholinergics in the management of overactive bladder.
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Affiliation(s)
- David R P Guay
- Institute for the Study of Geriatric Pharmacotherapy, Department of Experimental and Clinical Pharmacology, University of Minnesota College of Pharmacy, Minneapolis, Minnesota 55455, USA.
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16
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Kitazawa T, Asakawa K, Nakamura T, Teraoka H, Unno T, Komori SI, Yamada M, Wess J. M3 muscarinic receptors mediate positive inotropic responses in mouse atria: a study with muscarinic receptor knockout mice. J Pharmacol Exp Ther 2009; 330:487-93. [PMID: 19429792 DOI: 10.1124/jpet.109.153304] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The potential functional roles of M(3) muscarinic receptors in mouse atria were examined by pharmacological and molecular biological techniques, using wild-type mice, muscarinic M(2) or M(3) receptor single knockout (M(2)KO, M(3)KO), and M(2) and M(3) muscarinic receptor double knockout mice (M(2)/M(3)KO). Real-time quantitative reverse transcriptase-polymerase chain reaction analysis showed that the M(2) receptor mRNA was expressed predominantly in mouse atria but that the M(1), M(3), M(4), and M(5) receptor subtypes were also expressed at low levels. Carbachol (10 nM-30 microM) decreased the spontaneous beating frequency of right atria isolated from wild-type mice. Studies with subtype-preferring antagonists and atria from M(2)KO mice confirmed that this activity is mediated by the M(2) receptor subtype. In left atria from wild-type mice, carbachol decreased the amplitude of electrical field stimulation-evoked contractions (negative inotropic action), but this inhibition was transient and was followed by a gradual increase in contraction amplitude (positive inotropic response). In atria from M(3)KO mice, the transient negative inotropic action of carbachol changed to a sustained negative inotropic action. In contrast, in atria from M(2)KO mice, carbachol showed only positive inotropic activity. In atria from M(2)/M(3) double KO mice, carbachol was devoid of any inotropic activity. These observations, complemented by functional studies with subtype-preferring antagonists, convincingly demonstrate that atrial M(3) muscarinic receptors mediate positive inotropic effects in mouse atria. Physiologically, this activity may serve to dampen the inhibitory effects of M(2) receptor activation on atrial contractility.
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Affiliation(s)
- Takio Kitazawa
- Department of Pharmacology, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan.
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Kockskämper J, Zima AV, Roderick HL, Pieske B, Blatter LA, Bootman MD. Emerging roles of inositol 1,4,5-trisphosphate signaling in cardiac myocytes. J Mol Cell Cardiol 2008; 45:128-47. [PMID: 18603259 PMCID: PMC2654363 DOI: 10.1016/j.yjmcc.2008.05.014] [Citation(s) in RCA: 142] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2008] [Revised: 05/20/2008] [Accepted: 05/21/2008] [Indexed: 01/19/2023]
Abstract
Inositol 1,4,5-trisphosphate (IP(3)) is a ubiquitous intracellular messenger regulating diverse functions in almost all mammalian cell types. It is generated by membrane receptors that couple to phospholipase C (PLC), an enzyme which liberates IP(3) from phosphatidylinositol 4,5-bisphosphate (PIP(2)). The major action of IP(3), which is hydrophilic and thus translocates from the membrane into the cytoplasm, is to induce Ca(2+) release from endogenous stores through IP(3) receptors (IP(3)Rs). Cardiac excitation-contraction coupling relies largely on ryanodine receptor (RyR)-induced Ca(2+) release from the sarcoplasmic reticulum. Myocytes express a significantly larger number of RyRs compared to IP(3)Rs (~100:1), and furthermore they experience substantial fluxes of Ca(2+) with each heartbeat. Therefore, the role of IP(3) and IP(3)-mediated Ca(2+) signaling in cardiac myocytes has long been enigmatic. Recent evidence, however, indicates that despite their paucity cardiac IP(3)Rs may play crucial roles in regulating diverse cardiac functions. Strategic localization of IP(3)Rs in cytoplasmic compartments and the nucleus enables them to participate in subsarcolemmal, bulk cytoplasmic and nuclear Ca(2+) signaling in embryonic stem cell-derived and neonatal cardiomyocytes, and in adult cardiac myocytes from the atria and ventricles. Intriguingly, expression of both IP(3)Rs and membrane receptors that couple to PLC/IP(3) signaling is altered in cardiac disease such as atrial fibrillation or heart failure, suggesting the involvement of IP(3) signaling in the pathology of these diseases. Thus, IP(3) exerts important physiological and pathological functions in the heart, ranging from the regulation of pacemaking, excitation-contraction and excitation-transcription coupling to the initiation and/or progression of arrhythmias, hypertrophy and heart failure.
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Affiliation(s)
- Jens Kockskämper
- Division of Cardiology, Medical University of Graz,, Auenbruggerplatz 15, A-8036 Graz, Austria
| | - Aleksey V. Zima
- Department of Molecular Biophysics & Physiology, Rush University, 1750 W. Harrison St., Chicago, IL 60612, USA
| | - H. Llewelyn Roderick
- Laboratory of Molecular Signalling, Babraham Institute, Cambridge CB2 4AT, UK
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1 PD, UK
| | - Burkert Pieske
- Division of Cardiology, Medical University of Graz,, Auenbruggerplatz 15, A-8036 Graz, Austria
| | - Lothar A. Blatter
- Department of Molecular Biophysics & Physiology, Rush University, 1750 W. Harrison St., Chicago, IL 60612, USA
| | - Martin D. Bootman
- Laboratory of Molecular Signalling, Babraham Institute, Cambridge CB2 4AT, UK
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The detection of the non-M2 muscarinic receptor subtype in the rat heart atria and ventricles. Naunyn Schmiedebergs Arch Pharmacol 2008; 378:103-16. [PMID: 18443764 DOI: 10.1007/s00210-008-0285-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2004] [Accepted: 03/17/2008] [Indexed: 10/22/2022]
Abstract
Mammal heart tissue has long been assumed to be the exclusive domain of the M(2) subtype of muscarinic receptor, but data supporting the presence of other subtypes also exist. We have tested the hypothesis that muscarinic receptors other than the M(2) subtype are present in the heart as minor populations. We used several approaches: a set of competition binding experiments with pirenzepine, AFDX-116, 4-DAMP, PD 102807, p-F-HHSiD, AQ-RA 741, DAU 5884, methoctramine and tripinamide, blockage of M(1) muscarinic receptors using MT7 toxin, subtype-specific immunoprecipitation experiments and determination of phospholipase C activity. We also attempted to block M(1)-M(4) receptors using co-treatment with MT7 and AQ-RA 741. Our results show that only the M(2) subtype is present in the atria. In the ventricles, however, we were able to determine that 20% (on average) of the muscarinic receptors were subtypes other than M(2), with the majority of these belonging to the M(1) subtype. We were also able to detect a marginal fraction (6 +/- 2%) of receptors that, based on other findings, belong mainly to the M(5) muscarinic receptors. Co-treatment with MT7 and AQ-RA 741 was not a suitable tool for blocking of M(1)-M(4) receptors and can not therefore be used as a method for M(5) muscarinic receptor detection in substitution to crude venom. These results provide further evidence of the expression of the M(1) muscarinic receptor subtype in the rat heart and also show that the heart contains at least one other, albeit minor, muscarinic receptor population, which most likely belongs to the M(5) muscarinic receptors but not to that of the M(3) receptors.
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Andersson KE, Olshansky B. Treating patients with overactive bladder syndrome with antimuscarinics: heart rate considerations. BJU Int 2007; 100:1007-14. [PMID: 17922785 DOI: 10.1111/j.1464-410x.2007.07100.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this excellent mini-review, the authors present an extensive and relevant paper on the effect of antimuscarinic agents on the heart. This is without doubt the most detailed and the most reader-friendly paper on this subject, and I am sure that it will help urologists to assist in further educating their patients when prescribing these compounds.
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Affiliation(s)
- Karl-Erik Andersson
- Wake Forest Institute for Regenerative Medicine, Wake Forest University School of Medicine, Winston Salem, NC, USA
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20
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M3 cholinergic receptors are involved in postnatal development of cholinergic regulation of cardiac activity in rats. Bull Exp Biol Med 2007; 144:171-3. [DOI: 10.1007/s10517-007-0281-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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21
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Yeh YH, Qi X, Shiroshita-Takeshita A, Liu J, Maguy A, Chartier D, Hebert T, Wang Z, Nattel S. Atrial tachycardia induces remodelling of muscarinic receptors and their coupled potassium currents in canine left atrial and pulmonary vein cardiomyocytes. Br J Pharmacol 2007; 152:1021-32. [PMID: 17618308 PMCID: PMC2095106 DOI: 10.1038/sj.bjp.0707376] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE Both parasympathetic tone and atrial tachycardia (AT) remodelling of ion channels play important roles in atrial fibrillation (AF) pathophysiology. Different muscarinic cholinergic receptor (mAChR) subtypes (M2, M3, M4) in atrial cardiomyocytes are coupled to distinct K+-currents (called IKM2, IKM3, IKM4, respectively). Pulmonary veins (PVs) are important in AF and differential cholinergic current responses are a potential underlying mechanism. This study investigated AT-induced remodelling of mAChR subtypes and K+-currents in left-atrial (LA) and PV cardiomyocytes. EXPERIMENTAL APPROACH Receptor expression was assayed by western blot. IKM2, IKM3 and IKM4 were recorded with whole-cell patch-clamp in LA and PV cardiomyocytes of nonpaced control dogs and dogs after 7 days of AT-pacing (400 bpm). KEY RESULTS Current densities of IKM2, IKM3 and IKM4 were significantly reduced by AT-pacing in LA and PV cardiomyocytes. PV cardiomyocyte current-voltage relations were similar to LA for all three cholinergic currents, both in control and AT remodelling. Membrane-protein expression levels corresponding to M2, M3 and M4 subtypes were decreased significantly (by about 50%) after AT pacing. Agonist concentration-response relations for all three currents were unaffected by AT pacing. CONCLUSIONS AND IMPLICATIONS AT downregulated all three mAChR-coupled K+-current subtypes, along with corresponding mAChR protein expression. These changes in cholinergic receptor-coupled function may play a role in AF pathophysiology. Cholinergic receptor-coupled K+-currents in PV cardiomyocytes were similar to those in LA under control and AT-pacing conditions, suggesting that differential cholinergic current properties do not explain the role of PVs in AF.
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MESH Headings
- Animals
- Atrial Fibrillation/metabolism
- Atrial Fibrillation/physiopathology
- Blotting, Western
- Cardiac Pacing, Artificial
- Cells, Cultured
- Disease Models, Animal
- Dogs
- Down-Regulation
- Electrophysiologic Techniques, Cardiac
- Evoked Potentials
- Heart Atria/metabolism
- Heart Atria/pathology
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/pathology
- Patch-Clamp Techniques
- Potassium Channels, Inwardly Rectifying/metabolism
- Pulmonary Veins/metabolism
- Pulmonary Veins/pathology
- Receptors, Muscarinic/biosynthesis
- Receptors, Muscarinic/metabolism
- Tachycardia, Ectopic Atrial/metabolism
- Tachycardia, Ectopic Atrial/physiopathology
- Time Factors
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Affiliation(s)
- Y-H Yeh
- Department of Medicine, Université de Montréal and Research Center, Montreal Heart Institute Quebec, Canada
- Department of Medicine, Université de Montréal Quebec, Canada
- First Cardiovascular Division, Department of Medicine, Chang Gung Memorial Hospital, Chang Gung University Tao-Yuan, Taiwan
| | - X Qi
- Department of Medicine, Université de Montréal and Research Center, Montreal Heart Institute Quebec, Canada
- Department of Medicine, Université de Montréal Quebec, Canada
| | - A Shiroshita-Takeshita
- Department of Medicine, Université de Montréal and Research Center, Montreal Heart Institute Quebec, Canada
- Department of Medicine, Université de Montréal Quebec, Canada
| | - J Liu
- Department of Medicine, Université de Montréal and Research Center, Montreal Heart Institute Quebec, Canada
- Department of Medicine, Université de Montréal Quebec, Canada
| | - A Maguy
- Department of Medicine, Université de Montréal and Research Center, Montreal Heart Institute Quebec, Canada
- Department of Medicine, Université de Montréal Quebec, Canada
| | - D Chartier
- Department of Medicine, Université de Montréal and Research Center, Montreal Heart Institute Quebec, Canada
- Department of Medicine, Université de Montréal Quebec, Canada
| | - T Hebert
- Department of Pharmacology and Therapeutics, McGill University Quebec, Canada
| | - Z Wang
- Department of Medicine, Université de Montréal and Research Center, Montreal Heart Institute Quebec, Canada
- Department of Medicine, Université de Montréal Quebec, Canada
| | - S Nattel
- Department of Medicine, Université de Montréal and Research Center, Montreal Heart Institute Quebec, Canada
- Department of Medicine, Université de Montréal Quebec, Canada
- Department of Pharmacology and Therapeutics, McGill University Quebec, Canada
- Author for correspondence:
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Brattelid T, Tveit K, Birkeland JAK, Sjaastad I, Qvigstad E, Krobert KA, Hussain RI, Skomedal T, Osnes JB, Levy FO. Expression of mRNA encoding G protein-coupled receptors involved in congestive heart failure--a quantitative RT-PCR study and the question of normalisation. Basic Res Cardiol 2007; 102:198-208. [PMID: 17370034 DOI: 10.1007/s00395-007-0648-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2006] [Revised: 02/20/2007] [Accepted: 02/21/2007] [Indexed: 10/23/2022]
Abstract
Congestive heart failure (CHF) induces changes in the neurohumoral system and gene expression in viable myocardium. Several of these genes encode G protein-coupled receptors (GPCRs) involved in mechanisms which compensate for impaired myocardial function. We used real-time quantitative RT-PCR (Q-RT-PCR) to investigate the expression of mRNA encoding 15 different GPCRs possibly involved in CHF, and the effect of normalisation to GAPDH mRNA (GAPDH) or 18S rRNA (18S). CHF was induced in rats by coronary artery ligation, with sham-operated controls (Sham). After 6 weeks, mRNA expression in viable left ventricular myocardium was determined using both 18S and GAPDH as the normalisation standard. An apparent 30% reduction in GAPDH mRNA levels vs. 18S in CHF compared to Sham, although not significant in itself, influenced the interpretation of regulation of other genes.Thus, levels of mRNA encoding receptors for angiotensin II (AT(1)), endothelin (ET(A), ET(B)) and the muscarinic acetylcholine (mACh) receptor M(1) increased significantly in CHF only when normalised to GAPDH. Levels of mRNA encoding the mACh receptors M(3) and M(4) and the serotonin receptors 5-HT(2A) and 5-HT(4) increased, whereas alpha(1D)-adrenoceptor mRNA decreased in CHF irrespective of the normalisation standard. No significant change was detected for M2 and M5 mACh receptors or alpha(1A)-, alpha(1B)-, beta(1)- or beta(2)-adrenoceptors. Q-RT-PCR is a sensitive and powerful method to monitor changes in GPCR mRNA expression in CHF. However, the normalisation standard used is important for the interpretation of mRNA regulation.
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Affiliation(s)
- Trond Brattelid
- Dept. of Pharmacology, University of Oslo, 1057, Blindern, 0316 Oslo, Norway
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Hogan K, Markos F. Muscarinic type 1 receptors mediate part of nitric oxide’s vagal facilitatory effect in the isolated innervated rat right atrium. Nitric Oxide 2007; 16:110-7. [PMID: 16843016 DOI: 10.1016/j.niox.2006.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2006] [Revised: 05/08/2006] [Accepted: 05/31/2006] [Indexed: 11/26/2022]
Abstract
We investigated whether vagal cardiac cholinergic facilitation by nitric oxide (NO) is mediated by cardiac muscarinic receptor subtypes in the vagally innervated rat right atrium in vitro. Experiments were carried out in the presence of atenolol (4 microM). The right vagus was stimulated at 4, 8, 16, 32 Hz; pulse duration 1 ms at 20 V for 20s; vagal postganglionic activation was achieved using nicotine (0.1, 0.3, 0.5, 1mM) and the effect on cardiac interval (ms) assessed. Pirenzepine (1 microM), a M1 antagonist, attenuated vagally induced increase in cardiac interval. L-Arginine (0.34 mM) superfused with pirenzepine failed to reverse this attenuation, however, L-arginine applied alone reversed the reduction vagal cardiac slowing. Similarly, sodium nitroprusside (10 microM) applied alone, and not together with pirenzepine, was able to reverse the attenuation of vagal effects caused by pirenzepine. Synthetic MT7 (1 nM) toxin, a selective M1 antagonist confirmed these results. M3 antagonism using para-fluorohexahydrosiladifenidol (p-F-HHSiD) (300 nM) and M4 antagonism with PD 102807 (200 nM) did not affect the vagally induced increase in cardiac interval. Nicotine induced increase in cardiac interval was not altered by pirenzepine. These results show that antagonism of M1 receptors on cardiac vagal preganglionic fibres reduces vagal efficacy which can be recovered by either a nitric oxide synthase substrate or a NO donor.
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Affiliation(s)
- K Hogan
- School of Pharmacy & Pharmaceutical Sciences, Trinity College Dublin, Dublin 2, Ireland
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Pérez CCN, Tobar IDB, Jiménez E, Castañeda D, Rivero MB, Concepción JL, Chiurillo MA, Bonfante-Cabarcas R. Kinetic and molecular evidences that human cardiac muscle express non-M2 muscarinic receptor subtypes that are able to interact themselves. Pharmacol Res 2006; 54:345-55. [PMID: 16965921 DOI: 10.1016/j.phrs.2006.07.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2006] [Revised: 05/19/2006] [Accepted: 07/03/2006] [Indexed: 11/21/2022]
Abstract
In heart tissue five isoforms of the muscarinic acetylcholine receptor (mAChR) have been identified, designated m1-m5, of which only M1, M2 and M3 have functional evidences for their role in cardiac physiology. The present study was designed to explore the diversity of mAChR subtypes in human hearts and determine whether these subtypes are able to interact themselves. Expression of mRNAs encoding all five subtypes was readily detected by RT-PCR reaction in both atrial (A) and ventricle (V) samples. Immunoblotting, MABA and ELISA with subtype-specific antibodies confirmed the presence of M1, M2, M3, M4 and M5 proteins in membrane preparations from both A and V. Kinetic characterization using [(3)H]-QNB shown: (1) atrium had greater B(max) than did the ventricle, (2) [(3)H]-QNB behave as an allosteric modulator, inducing cooperativity at high and disclosing heterogeneity at low concentrations, (3) heterogenity was observed in pirenzepine, biperiden and tropicamide competition curves, being the high affinity sites compatible with M1 and M4 muscarinic receptor subtypes and (4) methoctramine competition curves in presence of selective muscarinic receptor subtypes antagonist displayed heterogeneity profile still maintaining cooperativity (n(H)>1), indicating muscarinic receptors subtypes are able to form homo- and hetero-oligomers. In conclusion, our results provide molecular and kinetic evidence for the presence of multiple subtypes of mAChR in human hearts, which are able to undergo discrete transitions from a non-cooperative kinetics of non-interacting monomers to a cooperative kinetics of interacting oligomers.
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Affiliation(s)
- Carmen Carlota Nello Pérez
- Unidad de Bioquímica Dr. José Antonio Moreno Yánes, Escuela de Medicina Pablo Acosta Ortiz, Universidad Centro Occidental Lisandro Alvarado, Avenida Libertador con Avenida Andrés Bello, Barquisimeto, Estado Lara, Código 3001, Venezuela
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Abrams P, Andersson KE, Buccafusco JJ, Chapple C, de Groat WC, Fryer AD, Kay G, Laties A, Nathanson NM, Pasricha PJ, Wein AJ. Muscarinic receptors: their distribution and function in body systems, and the implications for treating overactive bladder. Br J Pharmacol 2006; 148:565-78. [PMID: 16751797 PMCID: PMC1751864 DOI: 10.1038/sj.bjp.0706780] [Citation(s) in RCA: 396] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
1. The effectiveness of antimuscarinic agents in the treatment of the overactive bladder (OAB) syndrome is thought to arise through blockade of bladder muscarinic receptors located on detrusor smooth muscle cells, as well as on nondetrusor structures. 2. Muscarinic M3 receptors are primarily responsible for detrusor contraction. Limited evidence exists to suggest that M2 receptors may have a role in mediating indirect contractions and/or inhibition of detrusor relaxation. In addition, there is evidence that muscarinic receptors located in the urothelium/suburothelium and on afferent nerves may contribute to the pathophysiology of OAB. Blockade of these receptors may also contribute to the clinical efficacy of antimuscarinic agents. 3. Although the role of muscarinic receptors in the bladder, other than M3 receptors, remains unclear, their role in other body systems is becoming increasingly well established, with emerging evidence supporting a wide range of diverse functions. Blockade of these functions by muscarinic receptor antagonists can lead to similarly diverse adverse effects associated with antimuscarinic treatment, with the range of effects observed varying according to the different receptor subtypes affected. 4. This review explores the evolving understanding of muscarinic receptor functions throughout the body, with particular focus on the bladder, gastrointestinal tract, eye, heart, brain and salivary glands, and the implications for drugs used to treat OAB. The key factors that might determine the ideal antimuscarinic drug for treatment of OAB are also discussed. Further research is needed to show whether the M3 selective receptor antagonists have any advantage over less selective drugs, in leading to fewer adverse events.
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Affiliation(s)
- Paul Abrams
- Bristol Urological Institute, Southmead Hospital, Westbury-on-Trym, Bristol BS10 5NB.
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Zefirov TL, Ziyatdinova NI, Saifutdinova LR, Zefirov AL. Cardiac activity and blood pressure in rats during selective blockade of various subtypes of muscarinic cholinoceptors. Bull Exp Biol Med 2006; 141:662-5. [PMID: 17364043 DOI: 10.1007/s10517-006-0246-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Cardiac activity and blood pressure in adult rats were recorded during selective blockade of cholinoceptors. Blockade of muscarinic M1 and M2-cholinoceptors had little effect on cardiac activity. Blockade of muscarinic M3-cholinoceptors was followed by heart acceleration. The data suggest that the tonic inhibitory influence of the vagus nerve is mediated via cardiac muscarinic M3-cholinoceptors. Electrostimulation of the right vagus nerve during selective blockade of various subtypes of muscarinic cholinoceptors was followed by the decrease in heart rate. Our results indicate that muscarinic cholinoceptors play a role in the immediate inhibition of cardiac activity upon vagus nerve stimulation.
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Affiliation(s)
- T L Zefirov
- Department of Anatomy, Physiology, and Human Health Care, Tatar State Humanitarian-and-Pedagogical University; Department of Normal Physiology, Kazan State Medical University.
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Yang B, Lin H, Xu C, Liu Y, Wang H, Han H, Wang Z. Choline produces cytoprotective effects against ischemic myocardial injuries: evidence for the role of cardiac m3 subtype muscarinic acetylcholine receptors. Cell Physiol Biochem 2006; 16:163-74. [PMID: 16301817 DOI: 10.1159/000089842] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/04/2005] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS Accumulating evidence indicates the presence of functional M3 subtype of acetylcholine muscarinic receptors (M(3)-mAChR), in addition to the well-recognized M(2)-mAChR, in the heart of various species including man. However, the pathophysiological role of the cardiac M(3)-mAChR remain undefined. This study was designed to explore the possible role of M(3)-mAChR in cytoprotection of myocardial infarction and several related signaling pathways as potential mechanisms. METHODS Studies were performed in a rat model of myocardial infarction and in isolated myocytes. RESULTS We found that choline relieved myocardial injuries during ischemia or under oxidative stress, which was achieved by correcting hemodynamic impairment, diminishing ventricular arrhythmias and protecting cardiomyocytes from apoptotic death. The beneficial effects of choline were reversed by the M(3)-selective antagonists but not by the M(2)-selective antagonist. Choline/M(3)-mAChR activated several survival signaling molecules (antiapoptotic proteins Bcl-2 and ERKs), increased endogenous antioxidant reserve (SOD), and reduced apoptotic mediators (proapoptotic proteins Fas and p38 MAPK) and intracellular Ca2+ overload. CONCLUSION Choline improves cardiac function and reduces ischemic myocardial injuries via stimulating the cardiac M(3)-mAChRs which in turn result in alterations of multiple signaling pathways leading to cytoprotection. The findings suggest M(3)-mAChR as a new target for drug development for improving cardiac function and preventing cardiac injuries during ischemia/reperfusion.
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Affiliation(s)
- Baofeng Yang
- Department of Pharmacology, State-Province Key Laboratory, Harbin Medical University, Harbin, Canada
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Brodde OE, Leineweber K. Autonomic receptor systems in the failing and aging human heart: similarities and differences. Eur J Pharmacol 2004; 500:167-76. [PMID: 15464030 DOI: 10.1016/j.ejphar.2004.07.022] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/01/2004] [Indexed: 11/21/2022]
Abstract
Changes in autonomic receptor systems (alpha- and beta-adrenoceptors and muscarinic receptors) were compared in the aging and failing human heart. In both settings responsiveness of beta-adrenoceptors and all other receptor systems that evoke their effects via cyclic AMP accumulation was diminished. Muscarinic receptor function, on the other hand, was decreased in the aging, but unchanged in the failing heart; in contrast, G protein-coupled receptor kinase activity was increased in the failing, but unchanged in the aging heart. alpha-Adrenoceptor function was unchanged or slightly decreased in the failing heart. However, nothing is known on alpha-adrenoceptor changes in the aging heart. These results indicate that in the failing human heart all autonomic receptor systems appear to be altered in the direction to attenuate beta-adrenoceptor responses to sympathetic (over)stimulation while in the aging human heart autonomic receptor systems appear to be altered in a direction that protects the heart against too pronounced reduction in beta-adrenoceptor responsiveness.
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Affiliation(s)
- Otto-Erich Brodde
- Departments of Pathophysiology and Nephrology, University of Essen School of Medicine, IG I., 9.OG, Hufelandstr. 55, D-45147 Essen, Germany.
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Wang Z, Shi H, Wang H. Functional M3 muscarinic acetylcholine receptors in mammalian hearts. Br J Pharmacol 2004; 142:395-408. [PMID: 15148264 PMCID: PMC1574958 DOI: 10.1038/sj.bjp.0705787] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2004] [Revised: 03/08/2004] [Accepted: 03/10/2004] [Indexed: 11/08/2022] Open
Abstract
In contrast to most peripheral tissues where multiple subtypes of muscarinic acetylcholine receptor (mAChR) coexist, with each of them playing its part in the orchestra of parasympathetic innervation, the myocardium has been traditionally considered to possess a single mAChR subtype. Although there is much evidence to support the notion that one receptor subtype (M2) orchestrates myocardial muscarinic transduction, there is emerging evidence that M1 and M3 receptors are also expressed and are of potential physiological, pathophysiological and pharmacological relevance. Clarifying this issue has a profound impact on our thinking about the cholinergic control of the heart function and disease and approaches to new drug development for the treatment of heart disease associated with parasympathetic dysfunction. This review article presents evidence for the presence of the M3 receptor subtype in the heart, and analyzes the controversial data from published pharmacological, functional and molecular studies. The potential roles of the M3 receptors, in parasympathetic control of heart function under normal physiological conditions and in heart failure, myocardial ischemia and arrhythmias, are discussed. On the basis of these considerations, we have made some proposals concerning the future of myocardial M3 receptor research.
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Affiliation(s)
- Zhiguo Wang
- Research Center, Montreal Heart Institute, University of Montreal, Montreal, Quebec, Canada.
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Shi H, Wang H, Yang B, Xu D, Wang Z. The M3 receptor-mediated K(+) current (IKM3), a G(q) protein-coupled K(+) channel. J Biol Chem 2004; 279:21774-8. [PMID: 15140874 DOI: 10.1074/jbc.c400100200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Stimulation of muscarinic acetylcholine receptors (mAChRs) can activate an inward rectifier K(+) current (I(KACh)), which is mediated by the M(2) subtype of mAChR in cardiac myocytes. Recently, a novel delayed rectifier-like K(+) current mediated by activation of the cardiac M(3) receptors (designated I(KM3)) was identified, which is distinct from I(KACh) and other known K(+) currents. While I(KACh) is known to be a G(i) protein-gated K(+) channel, the signal transduction mechanisms for I(KM3) activation remained unexplored. We studied I(KM3) with whole-cell patch clamp and macropatch clamp techniques. Whole cell I(KM3) activated by choline persisted with minimal rundown over 2 h in presence of internal GTP. When GTP was replaced by guanyl-5'-yl thiophosphate, I(KM3) demonstrated rapid and extensive rundown. While I(KACh) (induced by ACh) was markedly reduced in cells pretreated with pertussis toxin, I(KM3) was unaltered. Intracellular application of antibodies targeting alpha-subunit of G(i/o) protein suppressed I(KACh) without affecting I(KM3). Antibodies targeting the N and the C terminus, respectively, of G(q) protein alpha-subunit substantially depressed I(KM3) but failed to alter I(KACh). The antibody against beta-subunits of G proteins inhibited both I(KACh) and I(KM3). I(KM3) activated by choline in the cell-attached mode of macropatches persisted in the cell-free configuration. Application of purified G(q) protein alpha-subunit or betagamma-subunit of G proteins or guanosine 5'-O-(thiotriphosphate) to the internal solution activated I(KM3)-like currents in inside-out patches. Our findings revealed a novel aspect of receptor-channel signal transduction mechanisms, and I(KM3) represents the first G(q) protein-coupled K(+) channel. We propose that the G protein-coupled K(+) channel family could be divided into two subfamilies: G(i) protein-coupled K(+) channel subfamily and G(q) protein-coupled K(+) channel subfamily.
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Affiliation(s)
- Hong Shi
- Research Center, Montreal Heart Institute, Montreal, Quebec H1T 1C8, Canada
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