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7-Hydroxycoumarin Induces Vasorelaxation in Animals with Essential Hypertension: Focus on Potassium Channels and Intracellular Ca2+ Mobilization. Molecules 2022; 27:molecules27217324. [PMID: 36364149 PMCID: PMC9655823 DOI: 10.3390/molecules27217324] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 10/22/2022] [Accepted: 10/24/2022] [Indexed: 12/01/2022] Open
Abstract
Cardiovascular diseases (CVD) are the deadliest noncommunicable disease worldwide. Hypertension is the most prevalent risk factor for the development of CVD. Although there is a wide range of antihypertensive drugs, there still remains a lack of blood pressure control options for hypertensive patients. Additionally, natural products remain crucial to the design of new drugs. The natural product 7-hydroxycoumarin (7-HC) exhibits pharmacological properties linked to antihypertensive mechanisms of action. This study aimed to evaluate the vascular effects of 7-HC in an experimental model of essential hypertension. The isometric tension measurements assessed the relaxant effect induced by 7-HC (0.001 μM–300 μM) in superior mesenteric arteries isolated from hypertensive rats (SHR, 200–300 g). Our results suggest that the relaxant effect induced by 7-HC rely on K+-channels (KATP, BKCa, and, to a lesser extent, Kv) activation and also on Ca2+ influx from sarcolemma and sarcoplasmic reticulum mobilization (inositol 1,4,5-triphosphate (IP3) and ryanodine receptors). Moreover, 7-HC diminishes the mesenteric artery’s responsiveness to α1-adrenergic agonist challenge and improves the actions of the muscarinic agonist and NO donor. The present work demonstrated that the relaxant mechanism of 7-HC in SHR involves endothelium-independent vasorelaxant factors. Additionally, 7-HC reduced vasoconstriction of the sympathetic agonist while improving vascular endothelium-dependent and independent relaxation.
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Alves QL, Moraes RDA, Froes TQ, Castilho MS, Aquino de Araújo RS, Barbosa-Filho JM, Meira CS, Pereira Soares MB, Silva DF. Inhibition of intracellular Ca 2+ mobilization and potassium channels activation are involved in the vasorelaxation induced by 7-hydroxycoumarin. Eur J Pharmacol 2020; 887:173525. [PMID: 32889064 DOI: 10.1016/j.ejphar.2020.173525] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 08/24/2020] [Accepted: 08/28/2020] [Indexed: 11/30/2022]
Abstract
Coumarins exhibit a wide variety of biological effects, including activities in the cardiovascular system and the aim of this study was to evaluate the vascular therapeutic potential of 7-Hydroxicoumarin (7-HC). The vascular effects induced by 7-HC (0.001 μM-300 μM), were investigated by in vitro approaches using isometric tension measurements in rat superior mesenteric arteries and by in silico assays using Ligand-based analysis. Our results suggest that the vasorelaxant effect of 7-HC seems to rely on potassium channels, notably through large conductance Ca2+-activated K+ (BKCa) channels activation. In fact, 7-HC (300 μM) significantly reduced CaCl2-induced contraction as well as the reduction of intracellular calcium mobilization. However, the relaxation induced by 7-HC was independent of store-operated calcium entry (SOCE). Moreover, in silico analysis suggests that potassium channels have a common binding pocket, where 7-HC may bind and hint that its binding profile is more similar to quinine's than verapamil's. These results are compatible with the inhibition of Ca2+ release from intracellular stores, which is prompted by phenylephrine and caffeine. Taken together, these results demonstrate a therapeutic potential of 7-HC on the cardiovascular system, making it a promising lead compound for the development of drugs useful in the treatment of cardiovascular diseases.
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Affiliation(s)
- Quiara Lovatti Alves
- Laboratory of Cardiovascular Physiology and Pharmacology, Federal University of Bahia, Salvador, BA, 40110-902, Brazil; Gonçalo Moniz Institute, Oswaldo Cruz Foundation, FIOCRUZ, Bahia, Brazil
| | - Raiana Dos Anjos Moraes
- Laboratory of Cardiovascular Physiology and Pharmacology, Federal University of Bahia, Salvador, BA, 40110-902, Brazil; Gonçalo Moniz Institute, Oswaldo Cruz Foundation, FIOCRUZ, Bahia, Brazil
| | - Thamires Quadros Froes
- Laboratory of Bioinformatics and Molecular Modeling, Faculty of Pharmacy, Federal University of Bahia, Salvador, BA, 40170-115, Brazil
| | - Marcelo Santos Castilho
- Laboratory of Bioinformatics and Molecular Modeling, Faculty of Pharmacy, Federal University of Bahia, Salvador, BA, 40170-115, Brazil
| | - Rodrigo Santos Aquino de Araújo
- Laboratory of Pharmaceutical Technology, Department of Physiology and Pathology, Federal University of Paraíba, João Pessoa, PB, 58051-970, Brazil
| | - José Maria Barbosa-Filho
- Laboratory of Pharmaceutical Technology, Department of Physiology and Pathology, Federal University of Paraíba, João Pessoa, PB, 58051-970, Brazil
| | | | | | - Darízy Flávia Silva
- Laboratory of Cardiovascular Physiology and Pharmacology, Federal University of Bahia, Salvador, BA, 40110-902, Brazil; Gonçalo Moniz Institute, Oswaldo Cruz Foundation, FIOCRUZ, Bahia, Brazil.
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The ent-15α-Acetoxykaur-16-en-19-oic Acid Relaxes Rat Artery Mesenteric Superior via Endothelium-Dependent and Endothelium-Independent Mechanisms. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2013; 2012:472821. [PMID: 23346202 PMCID: PMC3545360 DOI: 10.1155/2012/472821] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 11/07/2012] [Accepted: 11/13/2012] [Indexed: 01/15/2023]
Abstract
The objective of the study was to investigate the mechanism of the relaxant activity of the ent-15α-acetoxykaur-16-en-19-oic acid (KA-acetoxy). In rat mesenteric artery rings, KA-acetoxy induced a concentration-dependent relaxation in vessels precontracted with phenylephrine. In the absence of endothelium, the vasorelaxation was significantly shifted to the right without reduction of the maximum effect. Endothelium-dependent relaxation was significantly attenuated by pretreatment with L-NAME, an inhibitor of the NO-synthase (NOS), indomethacin, an inhibitor of the cyclooxygenase, L-NAME + indomethacin, atropine, a nonselective antagonist of the muscarinic receptors, ODQ, selective inhibitor of the guanylyl cyclase enzyme, or hydroxocobalamin, a nitric oxide scavenger. The relaxation was completely reversed in the presence of L-NAME + 1 mM L-arginine or L-arginine, an NO precursor. Diterpene-induced relaxation was not affected by TEA, a nonselective inhibitor of K+ channels. The KA-acetoxy antagonized CaCl2-induced contractions in a concentration-dependent manner and also inhibited an 80 mM KCl-induced contraction. The KA-acetoxy did not interfere with Ca2+ release from intracellular stores. The vasorelaxant induced by KA-acetoxy seems to involve the inhibition of the Ca2+ influx and also, at least in part, by endothelial muscarinic receptors activation, NO and PGI2 release.
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Silva-Filho JC, Oliveira NNPM, Arcanjo DDR, Quintans-Júnior LJ, Cavalcanti SCH, Santos MRV, Oliveira RDCM, Oliveira AP. Investigation of mechanisms involved in (-)-borneol-induced vasorelaxant response on rat thoracic aorta. Basic Clin Pharmacol Toxicol 2011; 110:171-7. [PMID: 21883938 DOI: 10.1111/j.1742-7843.2011.00784.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The monoterpene (-)-borneol is present in essential oils of several medicinal plants. The aim of this study was to evaluate (-)-borneol effects on rat thoracic aorta artery rings. The cumulative addition of (-)-borneol (10(-9) -3 × 10(-4) M) on a phenylephrine-induced pre-contraction (10(-6) M) promoted a vasorelaxant effect in a concentration-dependent manner and independent of vascular endothelium. A similar effect was obtained on KCl-induced pre-contractions (80 mM). (-)-Borneol (10(-5) -3 × 10(-4 ) M) inhibited contractions induced by cumulative addition of CaCl2 (10(-6) -3 × 10(-2) M) in depolarizing medium without Ca(2+) in a concentration-dependent manner. On S-(-) Bay K 8644-induced pre-contractions (10(-7) M), (-)-borneol did not induce significant changes compared with KCl-induced pre-contractions. In a Ca(2+) -free medium, (-)-borneol (10(-5) , 10(-4) or 10(-3) M) interfered in calcium mobilization from phenylephrine (10(-6) M)- or caffeine (20 mM)-sensitive intracellular stores. The involvement of K(+) channels was evaluated by tetraethylammonium (3 mM), 4-aminopyridine (1 mM) and glibenclamide (10(-5) M) pre-treatment, and (-)-borneol-induced vasorelaxation was markedly attenuated. Thus, this vasorelaxant effect can probably be attributed to calcium influx blockade through voltage-operated calcium channels (CaV L), calcium mobilization from intracellular stores and potassium channels activation.
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Affiliation(s)
- José Couras Silva-Filho
- Medicinal Plants Research Center, Federal University of Piauí, BrazilDepartament of Physiology, Federal University of Sergipe, Brazil
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Araújo-Júnior JX, Nogueira Ribeiro ÊA, Manssour Fraga CA, Lima LM, Barreiro EJ, De Medeiros IA. Cardiovascular effects induced by N-(4'-dihydro)-piperoylthiomorpholine in normotensive rats. J Pharm Pharmacol 2010; 62:1794-800. [DOI: 10.1111/j.2042-7158.2010.01143.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Abstract
Objectives
We have tested the cardiovascular effects of N-(4′-dihydro)-piperoylthiomorpholine (LASSBio 365) on rats using an in-vivo and in-vitro approach.
Methods
LASSBio 365 (0.025, 0.05, 0.1, 0.25, 0.5 or 1 mg/kg, randomly injected) was administered to conscious unrestrained rats and the mean arterial pressure and heart rate were measured. The effects of LASSBio 365 (3 × 10−6–3 × 10−4m) on rat isolated aortic rings with and without endothelium were investigated.
Key findings
LASSBio 365 induced a dose-dependent decrease in mean arterial pressure and heart rate (ED50 = 158 ± 53 µg/kg). The effects evoked by LASSBio 365 (0.5 mg/kg) were inhibited by pretreatment with atropine. In anaesthetized rats, electrocardiogram recordings revealed second/third degree sinoatrial and atrioventricular blockade induced by the compound, which were completely inhibited after cardiac muscarinic blockade or cervical bilateral vagotomy. In rat isolated aortic rings, LASSBio 365 (3 × 10−6–3 × 10−4m) was capable of antagonizing the contractile effects induced by phenylephrine (1 µm) or KCl (80 mm) (IC50 = 107 ± 6; 92 ± 6 µm, respectively). This effect was not inhibited after removal of the vascular endothelium (IC50 = 84 ± 4; 92 ± 10 µm, respectively). LASSBio 365 (10−6–10−4m) antagonized CaCl2-induced contractions in a concentration-dependent manner. Furthermore, LASSBio 365 (98 µm) inhibited contractions produced by noradrenaline (1 µm), but not those induced by caffeine (20 mm).
Conclusions
These results suggested that LASSBio 365 produced negative chronotropism and reduced peripheral resistance that were probably due to the stimulation of cardiac muscarinic pathways. Peripheral vasodilation was probably linked to voltage-dependent Ca2+-channel blockade and/or specific inhibition of Ca2+ release from noradrenaline-sensitive intracellular stores.
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Affiliation(s)
- João Xavier Araújo-Júnior
- Laboratório de Avaliação e Síntese de Substâncias Bioativas (LASSBio), Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro-RJ, Brazil
- Escola de Enfermagem e Farmácia, Universidade Federal de Alagoas, Cidade Universitária, Tabuleiro dos Martins, Maceió-AL, Brazil
- Instituto de Química e Biotecnologia, Universidade Federal de Alagoas, Maceió-AL, Brazil
| | - Êurica Adélia Nogueira Ribeiro
- Escola de Enfermagem e Farmácia, Universidade Federal de Alagoas, Cidade Universitária, Tabuleiro dos Martins, Maceió-AL, Brazil
| | - Carlos Alberto Manssour Fraga
- Laboratório de Avaliação e Síntese de Substâncias Bioativas (LASSBio), Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro-RJ, Brazil
| | - Lídia Moreira Lima
- Laboratório de Avaliação e Síntese de Substâncias Bioativas (LASSBio), Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro-RJ, Brazil
| | - Eliezer Jesus Barreiro
- Laboratório de Avaliação e Síntese de Substâncias Bioativas (LASSBio), Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro-RJ, Brazil
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Bastos JFA, Moreira IJA, Ribeiro TP, Medeiros IA, Antoniolli AR, De Sousa DP, Santos MRV. Hypotensive and vasorelaxant effects of citronellol, a monoterpene alcohol, in rats. Basic Clin Pharmacol Toxicol 2009; 106:331-7. [PMID: 20002067 DOI: 10.1111/j.1742-7843.2009.00492.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Citronellol is an essential oil constituent from the medicinal plants Cymbopogon citratus, Cymbopogon winterianus and Lippia alba which are thought to possess antihypertensive properties. Citronellol-induced cardiovascular effects were evaluated in this study. In rats, citronellol (1-20 mg/kg, i.v.) induced hypotension, which was not affected by pre-treatment with atropine, hexamethonium, N(omega)-nitro-L-arginine methyl ester hydrochloride or indomethacin, and tachycardia, which was only attenuated by pre-treatment with atropine and hexamethonium. These responses were less than those obtained for nifedipine, a reference drug. In intact rings of rat mesenteric artery pre-contracted with 10 microM phenylephrine, citronellol induced relaxations (pD(2) = 0.71 +/- 0.11; E(max) = 102 +/- 5%; n = 6) that were not affected by endothelium removal, after tetraethylamonium in rings without endothelium pre-contracted with KCl 80 mM. Citronellol strongly antagonized (maximal inhibition = 97 +/- 4%; n = 6) the contractions induced by CaCl(2) (10(-6) to 3 x 10(-3 )M) and did not induce additional effects on the maximal response of nifedipine (10 microM). Finally, citronellol inhibited the contractions induced by 10 microM phenylephrine or 20 mM caffeine. The present results suggest that citronellol lowers blood pressure by a direct effect on the vascular smooth muscle leading to vasodilation.
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Affiliation(s)
- Joana F A Bastos
- Department of Physiology, Federal University of Sergipe, São Cristóvão-SE, Brazil
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Maciel SS, Dias KLG, Medeiros IA. Calcium mobilization as the endothelium-independent mechanism of action involved in the vasorelaxant response induced by the aqueous fraction of the ethanol extract of Albizia inopinata G. P. Lewis (AFL) in the rat aorta. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2004; 11:130-134. [PMID: 15070162 DOI: 10.1078/0944-7113-00361] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In a previous work, we demonstrated that, in normotensive rats, AFL induced a marked hypotension due to a decrease in total peripheral resistances (TPR), partially secondary to the release of NO by the endothelium. NO did not, however, account for the total vasodilation produced by AFL in these rats. The aim of this study was to determine the involvement of the intracellular calcium mobilization in the vasorelaxant action induced by AFL in the rat aorta. In aorta of normotensive rats AFL (10, 20, 40 and 80 microg/ml) inhibited the sustained contractions induced by KCl (80 and 30 mM) and phenylephrine (Phe, 1 microM) with similar IC50 values (54 +/- 6, 52 +/- 4 and 65 +/- 4 microg/ml, respectively). The relaxing response induced by AFL against Phe-induced contractions was modified significantly by the endothelium removal (IC50 = 132 +/- 23 and 65 +/- 4 microg/ml, endothelium removed and intact endothelium aortic rings, respectively). Nevertheless, removal of the endothelium did not significantly change IC50 values when KCl (30 and 80 mM) was used as the contractile agent. The inhibitory effect induced by AFL on high (64.5 mM) K+-induced contraction was potentiated slightly (p < 0.05) by the decrease (from 2.5 to 0.3 mM, Ca2+) and attenuated by the increase (from 2.5 to 7.5 mM Ca2+) in the external [Ca2+]. In addition, in aortas from normotensive rats, AFL antagonized transient contractions induced in Ca2+-free media induced by 1 microM noradrenaline in a concentration-dependent manner, but not those induced by 20 mM caffeine. It is suggested that the remaining vasodilator effect of AFL in normotensive rats is probably due to an inhibition of Ca2+ influx and/or inhibition of intracellular Ca2+ mobilization from the noradrenaline-sensitive stores.
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Affiliation(s)
- S S Maciel
- Laboratório de Tecnologia Farmacêutica, Universidade Federal da Paraíba, João Pessoa, Brazil.
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Abstract
1. The pharmacological effects of 14-deoxyandrographolide on rat isolated thoracic aorta were examined. 2. 14-Deoxyandrographolide (2.5-120 mumol/L) inhibited contractions induced by phenylephrine (PE; 0.1 mumol/L) and high K+ (80 mmol/L) in a concentration-dependent manner in endothelium-intact aorta. The effect was attenuated in endothelium-denuded aorta without modifying the maximal response. Like verapamil, 14-deoxyandrographolide produced a much greater vasorelaxant effect in aorta precontracted by KCl than by PE. 14-Deoxyandrographolide (20-60 mumol/L) also inhibited responses of the rat aorta to PE. 3. In Ca(2+)-free medium (KCl 55 mmol/L), 14-deoxyandrographolide (20-80 mumol/L) antagonized Ca(2+)-induced vasocontraction in a concentration-dependent manner and transient contractions induced by both caffeine (10 mmol/L) and nor-adrenaline (1 mumol/L) were suppressed or almost abolished by 14-deoxyandrographolide. 4. The vasorelaxant effect of 14-deoxyandrographolide was partially antagonized by NG-nitro-L-arginine methyl ester (25 mumol/L), a specific and competitive nitric oxide synthase (NOS) inhibitor, and methylene blue (10 mumol/L), a soluble guanylate cyclase inhibitor, but was not affected by indomethacin (20 mumol/L), a cyclo-oxygenase inhibitor, or glibenclamide (10 mumol/L), an ATP-sensitive K(+)-channel blocker. 5. These results suggest that the vasorelaxant activity of 14-deoxyandrographolide may be mediated via the activation of NOS and guanylate cyclase, as well as the blockade of Ca2+ influx through both voltage- and receptor-operated Ca2+ channels.
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Affiliation(s)
- C Y Zhang
- Department of Pharmacology, Faculty of Medicine, National University of Singapore, Singapore.
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Chen SJ, Huang YC, Wu BN, Chen IJ. Eugenolol: An eugenol-derived ?-adrenoceptor blocker with partial ?2-agonist and calcium mobilization inhibition associated vasorelaxant activities. Drug Dev Res 1997. [DOI: 10.1002/(sici)1098-2299(199703)40:3<239::aid-ddr4>3.0.co;2-l] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Tatsukawa Y, Arita M. Effects of KT-362, a sarcolemmal and intracellular calcium antagonist, on calcium transients of cultured neonatal rat ventricular cells: a comparison with gallopamil and ryanodine. Cardiovasc Drugs Ther 1997; 10:667-75. [PMID: 9110109 DOI: 10.1007/bf00053023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We evaluated the effects of KT-362 (5-[3-([2-(3,4-dimethoxyphenyl)-ethyl]amino)-1-oxopropyl]-2,3,4,5, -tetrahydro-1,5-benzothiazepine fumarate), a putative intracellular calcium antagonist, on the intracellular free calcium concentration ([Ca2+]i) of cultured neonatal rat ventricular cells using microfluorometry of fura-2. The effects were compared with those of gallopamil (D-600), a sarcolemmal calcium channel antagonist, and ryanodine, a modulator of sarcoplasmic reticulum (SR) function. KT-362 decreased both systolic [Ca2+]i (sCa) and diastolic [Ca2+]i (dCa) in cell aggregates, in a concentration (1, 3, 10, and 30 microM) and stimulation frequency (0.2, 0.5, and 1.0 Hz) dependent manner. The time to peak of the Ca2+ transient was significantly prolonged by KT-362 at a concentration of 30 microM, while the half-life of the Ca2+ transient was prolonged at concentrations of > or = 10 microM. Gallopamil (1 microM) decreased both sCa and dCa in a frequency (0.2, 0.5, and 1.0 Hz) dependent fashion, as was the case for KT-362, but did not change the time course of Ca2+ transients. Ryanodine (10 microM) prolonged the time to peak and half-life of the Ca2+ transient, as was also the case for KT-362, while the effect of ryanodine on dCa differed from that of KT-362. Finally, the effect of KT-362 on Ca2+ transients could be mimicked by simultaneous application of gallopamil and ryanodine. These results suggest that KT-362 is a novel compound that exerts depressant effects on both sarcolemmal Ca2+ channels, and perhaps Ca2+ release channels of the sarcoplasmic reticulum, in cultured neonatal rat ventricular cells.
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Affiliation(s)
- Y Tatsukawa
- Department of Physiology, Oita Medical University, Hasama, Japan
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Kiyosue T, Ito M, Cheng YN, Saikawa T, Arita M. KT-362, a Vasodilating and Antiarrhythmic Agent. ACTA ACUST UNITED AC 1996. [DOI: 10.1111/j.1527-3466.1996.tb00228.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Erker T, Laimer I, Huck S, Boehm S, Studenik C, Heistracher P. Synthesis and calcium antagonistic activity of 8-[N-[2-(3,4-dimethoxy- phenyl)ethyl]-beta-alanyl]-5,6,7,8-tetrahydrothieno[3,2-b][1,4]thiazepi ne fumarate. Arch Pharm (Weinheim) 1996; 329:347-51. [PMID: 8764883 DOI: 10.1002/ardp.19963290704] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
KT-362 is an antiarrhythmic and antihypertensive agent with vasodilating activity. Since it carries a homoveratryl group in the side chain, an obvious relation exists to the verapamil-type calcium antagonists. Replacement of the fused aromatic moiety in KT-362 with thiophene provided 8-[N-[2-(3,4-dimethoxyphenyl) ethyl]-beta-alanyl]-5,6,7,8-tetrahydrothieno[3,2-b][1,4] thiazepine (1). Compound 1 shows a negative chronotropic activity in spontaneously beating right atria (IC50 = 23 microM, n = 7), and a negative inotropic effect in papillary muscles (IC50 = 2.7 microM, n = 7) and left atria (IC50 = 4 microM, n = 6) of the guinea-pig heart. The decrease of contractility in papillary muscles could be antagonized by increasing the extracellular calcium concentration. Compound 1 was found to affect high (IC50: 70 +/- 5 microM) and low (IC50: 129 +/- 34 microM) voltage-activated calcium channel currents as well as voltage-activated sodium channel currents (IC50: 80 +/- 13 microM) in chick dorsal root ganglion neurons. In addition nicotine-induced currents were potently inhibited (IC50: 6 +/- 0.7 microM) in bovine chromaffin cells.
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Affiliation(s)
- T Erker
- Institute of Pharmaceutical Chemistry, University of Vienna, Austria
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Kaneko N. New 1,4-benzothiazepine derivative, K201, demonstrates cardioprotective effects against sudden cardiac cell death and intracellular calcium blocking action. Drug Dev Res 1994. [DOI: 10.1002/ddr.430330406] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Chuliá S, Ivorra MD, Lugnier C, Vila E, Noguera MA, D'Ocon P. Mechanism of the cardiovascular activity of laudanosine: comparison with papaverine and other benzylisoquinolines. Br J Pharmacol 1994; 113:1377-85. [PMID: 7889295 PMCID: PMC1510478 DOI: 10.1111/j.1476-5381.1994.tb17150.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
1. The activity of (+/-)-laudanosine, a benzyltetrahydroisoquinoline alkaloid, was investigated in pithed rats and rat isolated aorta. Its effects on [3H]-(+)-cis-diltiazem and [3H]-nitrendipine binding to rat cerebral cortical membranes, and on the different molecular forms of cyclic nucleotide phosphodiesterases (PDE) isolated from bovine aorta were investigated. 2. The dose-response curve to methoxamine (3-300 micrograms kg-1, i.v.) in normotensive pithed rats was shifted to the right by (+/-)-laudanosine, 3 and 6 mg kg-1. 3. (+/-)-Laudanosine inhibited in a concentration-dependent manner the contractile responses evoked by noradrenaline (NA 1 microM), depolarizing solution (KCl 80 mM) or depolarizing solution plus phentolamine (10 microM) in rat isolated aorta. The alkaloid appeared to be more potent against NA-induced contractions. 4. In Ca(2+)-free solution, (+/-)-laudanosine (100 microM) inhibited the contraction evoked by NA and did not modify the phasic contractile response evoked by caffeine. The alkaloid did not modify the refilling of the intracellular Ca(2+)-sotres sensitive to NA or caffeine. 5. (+/-)-Laudanosine inhibited [3H]-prazosin binding to cortical membranes and also inhibited [3H]-(+)-cis-diltiazem but with a lower potency. [3H]-nitrendipine binding was not affected by laudanosine. 6. (+/-)-Laudanosine does not have a significant effect on the different forms of PDEs isolated from bovine aorta. In contrast, compounds structurally related to this alkaloid such as papaverine and its derivatives, had a non-selective or more specific inhibitory effect on these PDE forms. These differences can be explained on the basis of their structural features: the planarity of the isoquinoline ring(papaverine) facilitates the interaction with receptor sites, and the different position of the benzyl group does not modify the activity unless this position leads to the presence of a chiral centre (laudanosine).7. These results suggest that (+/-)-laudanosine has a selective activity as an alpha1-adrenoceptor blocker. Its lack of action on different PDE forms provides us with information about a group of benzylisoquinolines that with small structural changes show a different effect on PDE-forms isolated from vascular smooth muscle.
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Affiliation(s)
- S Chuliá
- Departamento de Farmacologia, Facultad de Farmacia, Universitat de Valencia, Spain
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Ivorra MD, Chuliá S, Lugnier C, D'Ocon MP. Selective action of two aporphines at alpha 1-adrenoceptors and potential-operated Ca2+ channels. Eur J Pharmacol 1993; 231:165-74. [PMID: 8384112 DOI: 10.1016/0014-2999(93)90445-n] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Contractions evoked by noradrenaline (1 microM) or a depolarizing solution of 60 mM KCl were concentration dependently depressed by the aporphine alkaloids (S)-boldine and (R)-apomorphine in rat aorta. Both drugs had a greater inhibitory potency on the contraction elicited by noradrenaline. Dose-response curves for noradrenaline were shifted to the right in presence of (S)-boldine. (R)-Apomorphine acted by a complex mechanism at alpha 1-adrenoceptors and its inhibitory effect was irreversible. The conformational features of these alkaloids may explain their different behaviour at alpha 1-adrenoceptors. In Ca(2+)-free solution, the alkaloids inhibited the contraction evoked by noradrenaline but did not modify (apomorphine) or increase (boldine) the contractile response induced by caffeine. Both alkaloids interacted with [3H]prazosin binding and with the benzothiazepine binding site of the Ca2+ entry receptor complex but had no effect at the dihydropyridine binding site in the rat cerebral cortex. Both drugs showed some selectivity as inhibitors of [3H]prazosin binding as opposed to [3H]d-cis diltiazem binding. (R)-Apomorphine slightly inhibited one of the two forms of the Ca(2+)-independent, low Km cyclic AMP-phosphodiesterase (type IV), whereas it did not have a significant effect on the other phosphodiesterase forms. (S)-Boldine had negligible inhibitory effects on all phosphodiesterase forms. The present study provides evidence that (S)-boldine and (R)-apomorphine have interesting properties as Ca2+ entry blockers (through the benzothiazepine receptor site in the Ca2+ channel) and at alpha 1-adrenoceptors.
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Affiliation(s)
- M D Ivorra
- Departamento de Farmacologia, Facultad de Farmacia, Universitat de Valencia, Spain
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