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Seck I, Ndoye SF, Kapchoup MVK, Nguemo F, Ciss I, Ba LA, Ba A, Sokhna S, Seck M. Effects of plant extracts and derivatives on cardiac K +, Nav, and Ca v channels: a review. Nat Prod Res 2024:1-28. [PMID: 38586947 DOI: 10.1080/14786419.2024.2337112] [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: 11/14/2023] [Accepted: 03/24/2024] [Indexed: 04/09/2024]
Abstract
Natural products (NPs) are endless sources of compounds for fighting against several pathologies. Many dysfunctions, including cardiovascular disorders, such as cardiac arrhythmias have their modes of action regulation of the concentration of electrolytes inside and outside the cell targeting ion channels. Here, we highlight plant extracts and secondary metabolites' effects on the treatment of related cardiac pathologies on hERG, Nav, and Cav of cardiomyocytes. The natural product's pharmacology of expressed receptors like alpha-adrenergic receptors causes an influx of Ca2+ ions through receptor-operated Ca2+ ion channels. We also examine the NPs associated with cardiac contractions such as myocardial contractility by reducing the L-type calcium current and decreasing the intracellular calcium transient, inhibiting the K+ induced contractions, decreasing amplitude of myocyte shortening and showed negative ionotropic and chronotropic effects due to decreasing cytosolic Ca2+. We examine whether the NPs block potassium channels, particular the hERG channel and regulatory effects on Nav1.7.
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Affiliation(s)
- Insa Seck
- Laboratoire de Chimie de Coordination Organique, Université Cheikh Anta Diop de Dakar, Dakar, Senegal
- Laboratoire de Chimie Organique et Thérapeutique, Université Cheikh Anta Diop de Dakar, Dakar, Senegal
| | - Samba Fama Ndoye
- Laboratoire de Chimie Organique et Thérapeutique, Université Cheikh Anta Diop de Dakar, Dakar, Senegal
| | | | - Filomain Nguemo
- Institute of Neurophysiology, University of Cologne, Cologne, Germany
| | - Ismaila Ciss
- Laboratoire de Chimie Organique et Thérapeutique, Université Cheikh Anta Diop de Dakar, Dakar, Senegal
| | - Lalla Aicha Ba
- Laboratoire de Chimie Organique et Thérapeutique, Université Cheikh Anta Diop de Dakar, Dakar, Senegal
| | - Abda Ba
- Laboratoire de Chimie Organique et Thérapeutique, Université Cheikh Anta Diop de Dakar, Dakar, Senegal
| | - Seynabou Sokhna
- Laboratoire de Chimie Organique et Thérapeutique, Université Cheikh Anta Diop de Dakar, Dakar, Senegal
| | - Matar Seck
- Laboratoire de Chimie Organique et Thérapeutique, Université Cheikh Anta Diop de Dakar, Dakar, Senegal
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Wang J, Trinh TN, Vu ATV, Kim JC, Hoang ATN, Ohk CJ, Zhang YH, Nguyen CM, Woo SH. Chrysosplenol-C increases contraction by augmentation of sarcoplasmic reticulum Ca 2+ loading and release via protein kinase C in rat ventricular myocytes. Mol Pharmacol 2021; 101:13-23. [PMID: 34764211 DOI: 10.1124/molpharm.121.000365] [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: 07/08/2021] [Accepted: 10/11/2021] [Indexed: 11/22/2022] Open
Abstract
Naturally found chrysosplenol-C (4',5,6-trihydroxy-3,3',7-trimethoxyflavone) increases the contractility of cardiac myocytes independent of b-adrenergic signaling. We investigated the cellular mechanism for chrysosplenol-C-induced positive inotropy. Global and local Ca2+ signals, L-type Ca2+ current (ICa), and contraction were measured from adult rat ventricular myocytes using two-dimensional confocal Ca2+ imaging, the whole-cell patch clamp technique, and video-edge detection, respectively. Application of chrysosplenol-C reversibly increased Ca2+ transient magnitude with a maximal increase of ~55% within 2-3-min-exposures (EC50 =~21 mM). This chemical did not alter ICa and slightly increased diastolic Ca2+ level. The frequency and size of resting Ca2+ sparks were increased by chrysosplenol-C. Chrysosplenol-C significantly increased sarcoplasmic reticulum (SR) Ca2+ content but not fractional release. Pretreatment of protein kinase C (PKC) inhibitor, but not Ca2+/calmodulin-dependent protein kinase II (CaMKII) inhibitor, abolished the stimulatory effects of chrysosplenol-C on Ca2+ transients and Ca2+ sparks. Chrysosplenol-C-induced positive inotropy was removed by the inhibition of PKC, but not CaMKII or phospholipase C. Western blotting assessment revealed that PKC-δ protein level in the membrane fractions significantly increase within 2 min after chrysosplenol-C exposure with a delayed (5 min) increase in PKC-α levels in insoluble membrane. These results suggest that chrysosplenol-C enhances contractility via PKC (most likely PKC-δ)-dependent enhancement of SR Ca2+ releases in ventricular myocytes. Significance Statement We show that chrysosplenol-C, a natural flavone showing a positive inotropic effect, increases sarcoplasmic reticulum (SR) Ca2+ releases on depolarizations and Ca2+ sparks with an increase of SR Ca2+ loading, but not L-type Ca2+ current, in ventricular myocytes. Chrysosplenol-C-induced enhancement in contraction is eliminated by protein kinase C (PKC) inhibition, and it is associated with redistributions of PKC to the membrane. These indicate that chrysosplenol-C enhances contraction via PKC-dependent augmentations of SR Ca2+ release and Ca2+ loading during action potentials.
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Affiliation(s)
- Jun Wang
- Parmacy, Chungnam National University, Korea, Republic of
| | - Tran N Trinh
- Chungnam National University, Korea, Republic of
| | | | | | | | - Celine J Ohk
- Physiology, Seoul National University College of Medicine, Korea, Republic of
| | - Yin Hua Zhang
- Physiology, Seoul National University College of Medicine, Korea, Republic of
| | | | - Sun-Hee Woo
- Pharmacy, Chungnam National University, Korea, Republic of
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Kim JC, Le QA, Woo SH. Alterations of Ca 2+ signaling and Ca 2+ release sites in cultured ventricular myocytes with intact internal Ca 2+ storage. Biochem Biophys Res Commun 2020; 527:379-386. [PMID: 32321644 DOI: 10.1016/j.bbrc.2020.04.059] [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: 04/02/2020] [Accepted: 04/13/2020] [Indexed: 10/24/2022]
Abstract
Although cultured adult cardiac myocytes in combination with cell-level genetic modifications have been adopted for the study of protein function, the cellular alterations caused by the culture conditions themselves need to be clarified before we can interpret the effects of genetically altered proteins. We systematically compared the cellular morphology, global Ca2+ signaling, elementary Ca2+ release (sparks), and arrangement of ryanodine receptor (RyR) clusters in short-term (2 days)-cultured adult rat ventricular myocytes with those of freshly isolated myocytes. The transverse (t)-tubules were remarkably decreased (to ∼25%) by culture, and whole-cell capacitance was reduced by ∼35%. The magnitude of depolarization-induced Ca2+ transients decreased to ∼50%, and Ca2+ transient decay was slowed by culture. The culture did not affect sarcoplasmic reticulum (SR) Ca2+ loading. Therefore, fractional Ca2+ release was attenuated by culture. In the cultured cells, the L-type Ca2+ current (ICa) was smaller (∼50% of controls) and its inactivation was slower. In cultured myocytes, there were significantly fewer (∼50% of control) Ca2+ sparks, the local Ca2+ releases through RyR clusters, compared with in freshly isolated cells. Amplitude and kinetics (duration and time-to-peak) of individual sparks were similar, but they showed greater width in cultured cells. Immunolocalization analysis revealed that the cross-striation of RyRs distribution became weaker and less organized, and that the density of RyR clusters decreased in cultured myocytes. Our data suggest that the loss of t-tubules and generation of compromised Ca2+ transients and ICa in short-term adult ventricular cell culture are independent of SR Ca2+ loading status. In addition, the deteriorated arrangement of the RyR-clusters and their decreased density after short-term culture may be partly responsible for fewer Ca2+ sparks and a decrease in global Ca2+ release.
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Affiliation(s)
- Joon-Chul Kim
- Laboratory of Pathophysiology, College of Pharmacy, Chungnam National University, 99 Daehak-ro, Yuseong-Gu, Daejeon, 34134, South Korea
| | - Qui Anh Le
- Laboratory of Pathophysiology, College of Pharmacy, Chungnam National University, 99 Daehak-ro, Yuseong-Gu, Daejeon, 34134, South Korea
| | - Sun-Hee Woo
- Laboratory of Pathophysiology, College of Pharmacy, Chungnam National University, 99 Daehak-ro, Yuseong-Gu, Daejeon, 34134, South Korea.
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4
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Sun GC, Liang WZ, Jan CR. Mechanisms underlying the effect of an oral antihyperglycaemic agent glyburide on calcium ion (Ca 2+ ) movement and its related cytotoxicity in prostate cancer cells. Clin Exp Pharmacol Physiol 2019; 47:111-118. [PMID: 31529508 DOI: 10.1111/1440-1681.13177] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Revised: 09/07/2019] [Accepted: 09/10/2019] [Indexed: 10/26/2022]
Abstract
Glyburide is an agent commonly used to treat type 2 diabetes and also affects various physiological responses in different models. However, the effect of glyburide on Ca2+ movement and its related cytotoxicity in prostate cancer cells is unclear. This study examined whether glyburide altered Ca2+ signalling and viability in PC3 human prostate cancer cells and investigated those underlying mechanisms. Intracellular Ca2+ concentrations ([Ca2+ ]i ) in suspended cells were measured by using the fluorescent Ca2+ -sensitive dye fura-2. Cell viability was examined by WST-1 assay. Glyburide at concentrations of 100-1000 μM induced [Ca2+ ]i rises. Ca2+ removal reduced the signal by approximately 60%. In Ca2+ -containing medium, glyburide-induced Ca2+ entry was inhibited by 60% by protein kinase C (PKC) activator (phorbol 12-myristate 13 acetate, PMA) and inhibitor (GF109203X), and modulators of store-operated Ca2+ channels (nifedipine, econazole and SKF96365). Furthermore, glyburide induced Mn2+ influx suggesting of Ca2+ entry. In Ca2+ -free medium, inhibition of phospholipase C (PLC) with U73122 significantly inhibited glyburide-induced [Ca2+ ]i rises. Treatment with the endoplasmic reticulum (ER) Ca2+ pump inhibitor 2,5-di-tert-butylhydroquinone (BHQ) abolished glyburide-evoked [Ca2+ ]i rises. Conversely, treatment with glyburide abolished BHQ-evoked [Ca2+ ]i rises. Glyburide at 100-500 μM decreased cell viability, which was not reversed by pretreatment with the Ca2+ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester (BAPTA/AM). Together, in PC3 cells, glyburide induced [Ca2+ ]i rises by Ca2+ entry via PKC-sensitive store-operated Ca2+ channels and Ca2+ release from the ER in a PLC-dependent manner. Glyburide also caused Ca2+ -independent cell death. This study suggests that glyburide could serve as a potential agent for treatment of prostate cancer.
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Affiliation(s)
- Gwo-Ching Sun
- Department of Anesthesiology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan, Republic of China.,Department of Anesthesiology, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, Republic of China
| | - Wei-Zhe Liang
- Department of Pharmacy, Tajen University, Pingtung, Taiwan, Republic of China.,Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan, Republic of China
| | - Chung-Ren Jan
- Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan, Republic of China
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Kim JC, Pérez-Hernández M, Alvarado FJ, Maurya SR, Montnach J, Yin Y, Zhang M, Lin X, Vasquez C, Heguy A, Liang FX, Woo SH, Morley GE, Rothenberg E, Lundby A, Valdivia HH, Cerrone M, Delmar M. Disruption of Ca 2+i Homeostasis and Connexin 43 Hemichannel Function in the Right Ventricle Precedes Overt Arrhythmogenic Cardiomyopathy in Plakophilin-2-Deficient Mice. Circulation 2019; 140:1015-1030. [PMID: 31315456 DOI: 10.1161/circulationaha.119.039710] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Plakophilin-2 (PKP2) is classically defined as a desmosomal protein. Mutations in PKP2 associate with most cases of gene-positive arrhythmogenic right ventricular cardiomyopathy. A better understanding of PKP2 cardiac biology can help elucidate the mechanisms underlying arrhythmic and cardiomyopathic events consequent to PKP2 deficiency. Here, we sought to capture early molecular/cellular events that can act as nascent arrhythmic/cardiomyopathic substrates. METHODS We used multiple imaging, biochemical and high-resolution mass spectrometry methods to study functional/structural properties of cells/tissues derived from cardiomyocyte-specific, tamoxifen-activated, PKP2 knockout mice (PKP2cKO) 14 days post-tamoxifen injection, a time point preceding overt electrical or structural phenotypes. Myocytes from right or left ventricular free wall were studied separately. RESULTS Most properties of PKP2cKO left ventricular myocytes were not different from control; in contrast, PKP2cKO right ventricular (RV) myocytes showed increased amplitude and duration of Ca2+ transients, increased Ca2+ in the cytoplasm and sarcoplasmic reticulum, increased frequency of spontaneous Ca2+ release events (sparks) even at comparable sarcoplasmic reticulum load, and dynamic Ca2+ accumulation in mitochondria. We also observed early- and delayed-after transients in RV myocytes and heightened susceptibility to arrhythmias in Langendorff-perfused hearts. In addition, ryanodine receptor 2 in PKP2cKO-RV cells presented enhanced Ca2+ sensitivity and preferential phosphorylation in a domain known to modulate Ca2+ gating. RNAseq at 14 days post-tamoxifen showed no relevant difference in transcript abundance between RV and left ventricle, neither in control nor in PKP2cKO cells. Instead, we found an RV-predominant increase in membrane permeability that can permit Ca2+ entry into the cell. Connexin 43 ablation mitigated the membrane permeability increase, accumulation of cytoplasmic Ca2+, increased frequency of sparks and early stages of RV dysfunction. Connexin 43 hemichannel block with GAP19 normalized [Ca2+]i homeostasis. Similarly, protein kinase C inhibition normalized spark frequency at comparable sarcoplasmic reticulum load levels. CONCLUSIONS Loss of PKP2 creates an RV-predominant arrhythmogenic substrate (Ca2+ dysregulation) that precedes the cardiomyopathy; this is, at least in part, mediated by a Connexin 43-dependent membrane conduit and repressed by protein kinase C inhibitors. Given that asymmetric Ca2+ dysregulation precedes the cardiomyopathic stage, we speculate that abnormal Ca2+ handling in RV myocytes can be a trigger for gross structural changes observed at a later stage.
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Affiliation(s)
- Joon-Chul Kim
- The Leon H. Charney Division of Cardiology (J.C.K., M.P.H., M.Z., X.L., C.V., M.C., M.D.), New York University School of Medicine
| | - Marta Pérez-Hernández
- The Leon H. Charney Division of Cardiology (J.C.K., M.P.H., M.Z., X.L., C.V., M.C., M.D.), New York University School of Medicine
| | - Francisco J Alvarado
- Department of Medicine and Cardiovascular Research Center, University of Wisconsin-Madison School of Medicine and Public Health (F.J.A., H.H.V.)
| | - Svetlana R Maurya
- Department of Biomedical Sciences (S.R.M., A.L.), Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Jerome Montnach
- Institut du Thorax, Nouvelle Universite a Nantes, INSERM, Nantes Cedex 1, France (J.M.)
| | - Yandong Yin
- Department of Pharmacology and Biochemistry (Y.Y., E.R.), New York University School of Medicine
| | - Mingliang Zhang
- The Leon H. Charney Division of Cardiology (J.C.K., M.P.H., M.Z., X.L., C.V., M.C., M.D.), New York University School of Medicine
| | - Xianming Lin
- The Leon H. Charney Division of Cardiology (J.C.K., M.P.H., M.Z., X.L., C.V., M.C., M.D.), New York University School of Medicine
| | - Carolina Vasquez
- The Leon H. Charney Division of Cardiology (J.C.K., M.P.H., M.Z., X.L., C.V., M.C., M.D.), New York University School of Medicine
| | - Adriana Heguy
- Department of Pathology and Genome Technology Center (A.H., G.E.M.), New York University School of Medicine
| | - Feng-Xia Liang
- Microscopy Laboratory, Division of Advanced Research Technologies (F.X.L.), New York University School of Medicine
| | - Sun-Hee Woo
- Laboratory of Physiology, College of Pharmacy, Chungam National University, Daejeon, South Korea (S.H.W.)
| | - Gregory E Morley
- Department of Pathology and Genome Technology Center (A.H., G.E.M.), New York University School of Medicine
| | - Eli Rothenberg
- Department of Pharmacology and Biochemistry (Y.Y., E.R.), New York University School of Medicine
| | - Alicia Lundby
- Department of Biomedical Sciences (S.R.M., A.L.), Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.,NNF Center for Protein Research (A.L.), Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Hector H Valdivia
- Department of Medicine and Cardiovascular Research Center, University of Wisconsin-Madison School of Medicine and Public Health (F.J.A., H.H.V.)
| | - Marina Cerrone
- The Leon H. Charney Division of Cardiology (J.C.K., M.P.H., M.Z., X.L., C.V., M.C., M.D.), New York University School of Medicine
| | - Mario Delmar
- The Leon H. Charney Division of Cardiology (J.C.K., M.P.H., M.Z., X.L., C.V., M.C., M.D.), New York University School of Medicine
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Kim JC, Wang J, Son MJ, Woo SH. Shear stress enhances Ca 2+ sparks through Nox2-dependent mitochondrial reactive oxygen species generation in rat ventricular myocytes. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:1121-1131. [PMID: 28213332 DOI: 10.1016/j.bbamcr.2017.02.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 02/01/2017] [Accepted: 02/12/2017] [Indexed: 02/06/2023]
Abstract
Shear stress enhances diastolic and systolic Ca2+ concentration in ventricular myocytes. Here, using confocal Ca2+ imaging in rat ventricular myocytes, we assessed the effects of shear stress (~16dyn/cm2) on the frequency of spontaneous Ca2+ sparks and explored the mechanism underlying shear-mediated Ca2+ spark regulation. The frequency of Ca2+ sparks was immediately increased by shear stress (by ~80%), and increased further (by ~150%) during prolonged exposure (20s). The 2-D size and duration of individual sparks were increased by shear stimulation. Inhibition of nitric oxide synthase (NOS) only partially attenuated the prolonged shear-mediated enhancement in spark frequency. Pretreatment with antioxidants significantly attenuated the short- and long-term effects of shear on spark frequency. Microtubule or nicotinamide adenine dinucleotide phosphate oxidase 2 (Nox2) inhibition abolished the immediate shear-induced increase in spark frequency and suppressed the effects of prolonged exposure to shear stress by ~70%. Scavenging of mitochondrial reactive oxygen species (ROS) and mitochondrial uncoupling also abolished the effect of short-term shear on spark occurrence, and markedly reduced (by ~80%) the effects of prolonged shear. Mitochondrial ROS levels increased under shear; this was eliminated by blocking Nox2. Sarcoplasmic reticulum Ca2+ content was increased only by prolonged shear. Our data suggest that shear stress enhances ventricular spark frequency mainly via ROS generated from mitochondria through Nox2, and that NOS and higher sarcoplasmic reticulum Ca2+ concentrations may also contribute to the enhancement of Ca2+ sparks under shear stress. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.
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Affiliation(s)
- Joon-Chul Kim
- Laboratory of Physiology, College of Pharmacy, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764, South Korea
| | - Jun Wang
- Laboratory of Physiology, College of Pharmacy, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764, South Korea
| | - Min-Jeong Son
- Laboratory of Physiology, College of Pharmacy, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764, South Korea
| | - Sun-Hee Woo
- Laboratory of Physiology, College of Pharmacy, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764, South Korea.
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Enhancement of contraction and L-type Ca2+ current by murrayafoline-A via protein kinase C in rat ventricular myocytes. Eur J Pharmacol 2016; 784:33-41. [DOI: 10.1016/j.ejphar.2016.05.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2016] [Revised: 04/30/2016] [Accepted: 05/04/2016] [Indexed: 11/17/2022]
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8
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Saponara S, Durante M, Spiga O, Mugnai P, Sgaragli G, Huong TT, Khanh PN, Son NT, Cuong NM, Fusi F. Functional, electrophysiological and molecular docking analysis of the modulation of Cav 1.2 channels in rat vascular myocytes by murrayafoline A. Br J Pharmacol 2015; 173:292-304. [PMID: 26493241 DOI: 10.1111/bph.13369] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Revised: 10/01/2015] [Accepted: 10/10/2015] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND AND PURPOSE The carbazole alkaloid murrayafoline A (MuA) enhances contractility and the Ca(2+) currents carried by the Cav 1.2 channels [ICa1.2 ] of rat cardiomyocytes. As only few drugs stimulate ICa1.2 , this study was designed to analyse the effects of MuA on vascular Cav 1.2 channels. EXPERIMENTAL APPROACH Vascular activity was assessed on rat aorta rings mounted in organ baths. Cav 1.2 Ba(2+) current [IBa1.2 ] was recorded in single rat aorta and tail artery myocytes by the patch-clamp technique. Docking at a 3D model of the rat, α1c central pore subunit of the Cav 1.2 channel was simulated in silico. KEY RESULTS In rat aorta rings MuA, at concentrations ≤14.2 μM, increased 30 mM K(+) -induced tone and shifted the concentration-response curve to K(+) to the left. Conversely, at concentrations >14.2 μM, it relaxed high K(+) depolarized rings and antagonized Bay K 8644-induced contraction. In single myocytes, MuA stimulated IBa1.2 in a concentration-dependent, bell-shaped manner; stimulation was stable, incompletely reversible upon drug washout and accompanied by a leftward shift of the voltage-dependent activation curve. MuA docked at the α1C subunit central pore differently from nifedipine and Bay K 8644, although apparently interacting with the same amino acids of the pocket. Neither Bay K 8644-induced stimulation nor nifedipine-induced block of IBa1.2 was modified by MuA. CONCLUSIONS AND IMPLICATIONS Murrayafoline A is a naturally occurring vasoactive agent able to modulate Cav 1.2 channels and dock at the α1C subunit central pore in a manner that differed from that of dihydropyridines.
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Affiliation(s)
- S Saponara
- Dipartimento di Scienze della Vita, Università degli Studi di Siena, Siena, Italy
| | - M Durante
- Dipartimento di Scienze della Vita, Università degli Studi di Siena, Siena, Italy
| | - O Spiga
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, Siena, Italy
| | - P Mugnai
- Dipartimento di Scienze della Vita, Università degli Studi di Siena, Siena, Italy
| | - G Sgaragli
- Dipartimento di Scienze della Vita, Università degli Studi di Siena, Siena, Italy
| | - T T Huong
- Institute of Natural Products Chemistry, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - P N Khanh
- Institute of Natural Products Chemistry, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - N T Son
- Institute of Natural Products Chemistry, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - N M Cuong
- Institute of Natural Products Chemistry, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - F Fusi
- Dipartimento di Scienze della Vita, Università degli Studi di Siena, Siena, Italy
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