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Vasorelaxant-Mediated Antihypertensive Effect of the Leaf Aqueous Extract from Stephania abyssinica (Dillon & A. Rich) Walp (Menispermaceae) in Rat. BIOMED RESEARCH INTERNATIONAL 2021; 2021:4730341. [PMID: 34660790 PMCID: PMC8519676 DOI: 10.1155/2021/4730341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 09/17/2021] [Indexed: 11/21/2022]
Abstract
Stephania abyssinica is a medicinal plant used in Cameroon alternative medicine to treat arterial hypertension (AHT). Previous in vitro studies demonstrated the endothelium nitric oxide-independent vasorelaxant property of the aqueous extract from Stephania abyssinica (AESA). But its effect on AHT is unknown. The present study was undertaken to explore other vasorelaxant mechanisms and to determine the antihypertensive effects of AESA in male Wistar rats. Phytochemical analysis of AESA was carried out using the liquid chromatography-mass spectrometry (LC-MS) method. The vasorelaxant effects of AESA (1-1000 μg/mL) were studied on rat isolated thoracic aorta rings, in the absence or presence of indomethacin (10 μM) or methylene blue (10 μM). The inhibitory effect of AESA on phenylephrine (PE, 10 μM) or KCl- (60 mM) induced contraction as well as the intracellular calcium release was also evaluated. The in vivo antihypertensive activity of AESA (43, 86, or 172 mg/kg/day) or captopril (20 mg/kg/day) administered orally was assessed in L-NAME- (40 mg/kg/day) treated rats. Blood pressure and heart rate (HR) were measured at the end of each week while serum or urinary nitric oxide (NO), creatinine, and glomerular filtration rate (GFR) were determined at the end of the 6 weeks of treatment, as well as histological analysis of the heart and the kidney. The LC-MS profiling of AESA identified 9 compounds including 7 alkaloids. AESA produced a concentration-dependent relaxation on contraction induced either by PE and KCl, which was significantly reduced in endothelium-denuded vessels, as well as in vessels pretreated with indomethacin and methylene blue. Moreover, AESA inhibited the intracellular Ca2+ release-induced contraction. In vivo, AESA reduced the AHT, heart rate (HR), and ventricular hypertrophy and increased serum NO, urine creatinine, and GFR. AESA also ameliorated heart and kidney lesions as compared to the L-NAME group. These findings supported the use of AESA as a potential antihypertensive drug.
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Zhang D, Krause BM, Schmalz HG, Wohlfart P, Yard BA, Schubert R. ET-CORM Mediated Vasorelaxation of Small Mesenteric Arteries: Involvement of Kv7 Potassium Channels. Front Pharmacol 2021; 12:702392. [PMID: 34552483 PMCID: PMC8451721 DOI: 10.3389/fphar.2021.702392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 08/24/2021] [Indexed: 11/18/2022] Open
Abstract
Although the vasoactive properties of carbon monoxide (CO) have been extensively studied, the mechanism by which CO mediates vasodilation is not completely understood. Through-out published studies on CO mediated vasodilation there is inconsistency on the type of K+-channels that are activated by CO releasing molecules (CORMs). Since the vasorelaxation properties of enzyme triggered CORMs (ET-CORMs) have not been studied thus far, we first assessed if ET-CORMs can mediate vasodilation of small mesenteric arteries and subsequently addressed the role of soluble guanylate cyclase (sGC) and that of K-channels herein. To this end, 3 different types of ET-CORMs that either contain acetate (rac-1 and rac-4) or pivalate (rac-8) as ester functionality, were tested ex vivo on methoxamine pre-contracted small rat mesenteric arteries in a myograph setting. Pre-contracted mesenteric arteries strongly dilated upon treatment with both types of acetate containing ET-CORMs (rac-1 and rac-4), while treatment with the pivalate containing ET-CORM (rac-8) resulted in no vasodilation. Pre-treatment of mesenteric arteries with the sGC inhibitor ODQ abolished rac-4 mediated vasodilation, similar as for the known sGC activator SNP. Likewise, rac-4 mediated vasodilation did not occur in KCL pretreated mesenteric arteries. Although mesenteric arteries abundantly expressed a variety of K+-channels only Kv7 channels were found to be of functional relevance for rac-4 mediated vasodilation. In conclusion the current results identified Kv7 channels as the main channel by which rac-4 mediates vasodilation. In keeping with the central role of Kv7 in the control of vascular tone and peripheral resistance these promising ex-vivo data warrant further in vivo studies, particularly in models of primary hypertension or cardiac diseases, to assess the potential use of ET-CORMs in these diseases.
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Affiliation(s)
- Danfeng Zhang
- Department of Nephrology, Endocrinology and Rheumatology, Fifth Medical Department of Medicine, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany.,Department of Nephrology, the Second Hospital of Anhui Medical University, Hefei, China
| | | | | | - Paulus Wohlfart
- Diabetes Research, Sanofi Aventis Deutschland GmbH, Frankfurt, Germany
| | - Benito A Yard
- Department of Nephrology, Endocrinology and Rheumatology, Fifth Medical Department of Medicine, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany.,European Center of Angioscience (ECAS), Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Frankfurt, Germany
| | - Rudolf Schubert
- European Center of Angioscience (ECAS), Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Frankfurt, Germany.,Physiology, Institute of Theoretical Medicine, Medical Faculty, University of Augsburg, Augsburg, Germany
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Shvetsova AA, Gaynullina DK, Tarasova OS, Schubert R. Remodeling of Arterial Tone Regulation in Postnatal Development: Focus on Smooth Muscle Cell Potassium Channels. Int J Mol Sci 2021; 22:ijms22115413. [PMID: 34063769 PMCID: PMC8196626 DOI: 10.3390/ijms22115413] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/15/2021] [Accepted: 05/18/2021] [Indexed: 11/30/2022] Open
Abstract
Maturation of the cardiovascular system is associated with crucial structural and functional remodeling. Thickening of the arterial wall, maturation of the sympathetic innervation, and switching of the mechanisms of arterial contraction from calcium-independent to calcium-dependent occur during postnatal development. All these processes promote an almost doubling of blood pressure from the moment of birth to reaching adulthood. This review focuses on the developmental alterations of potassium channels functioning as key smooth muscle membrane potential determinants and, consequently, vascular tone regulators. We present evidence that the pattern of potassium channel contribution to vascular control changes from Kir2, Kv1, Kv7 and TASK-1 channels to BKCa channels with maturation. The differences in the contribution of potassium channels to vasomotor tone at different stages of postnatal life should be considered in treatment strategies of cardiovascular diseases associated with potassium channel malfunction.
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Affiliation(s)
- Anastasia A. Shvetsova
- Department of Human and Animal Physiology, Faculty of Biology, M.V. Lomonosov Moscow State University, 119234 Moscow, Russia; (D.K.G.); (O.S.T.)
- Correspondence:
| | - Dina K. Gaynullina
- Department of Human and Animal Physiology, Faculty of Biology, M.V. Lomonosov Moscow State University, 119234 Moscow, Russia; (D.K.G.); (O.S.T.)
- Department of Physiology, Russian National Research Medical University, 117997 Moscow, Russia
| | - Olga S. Tarasova
- Department of Human and Animal Physiology, Faculty of Biology, M.V. Lomonosov Moscow State University, 119234 Moscow, Russia; (D.K.G.); (O.S.T.)
- Laboratory of Exercise Physiology, State Research Center of the Russian Federation-Institute for Biomedical Problems, Russian Academy of Sciences, 123007 Moscow, Russia
| | - Rudolf Schubert
- Physiology, Institute of Theoretical Medicine, Medical Faculty, University of Augsburg, 86159 Augsburg, Germany;
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Hassan AY, Maulood IM, Salihi A. The vasodilatory mechanism of nitric oxide and hydrogen sulfide in the human mesenteric artery in patients with colorectal cancer. Exp Ther Med 2021; 21:214. [PMID: 33500703 DOI: 10.3892/etm.2021.9646] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 08/19/2020] [Indexed: 12/24/2022] Open
Abstract
Recent studies have focused on the role of gasotransmitters in cancer progression and prevention. Therefore, the current study was designed to explore the vasodilator activity of NO and H2S in the human mesenteric arteries of patients with colorectal cancer (CRC) via the activation of K+ channels. A total of two sets of experiments were established for the current investigation. Blood samples from patients with CRC were obtained to detect serum levels of endocan and malondialdehyde (MDA). The role of K+ channels in mediating the vasodilation of the human mesenteric artery in response to sodium nitroprusside (SNP) and sodium disulfide (Na2S) was assessed. The level of serum endocan was indicated to be decreased in patients with CRC compared with healthy individuals, while the level of serum MDA remained unaltered between groups. The arterial rings pre-contracted with norepinephrine were first relaxed by the cumulative addition of increasing concentrations of either SNP (30 nM-30 µM) or (1-6 mM). Maximal relaxation rates were then calculated at 15 min intervals for 60 min. Pre-incubation of arterial rings for 20 min with individual K+ channel blockers was indicated to significantly reduce SNP- and Na2S-induced relaxation at different time points. Pre-treatment of L-nitro-arginine methyl ester did not alter vasodilation that was induced by Na2S. Furthermore, vasodilation of the CRC mesenteric artery was not altered by the synergistic application of SNP and Na2S, while pre-incubation of arterial rings with D,L-propargylglycine significantly enhanced vasodilation induced by SNP. These results indicated that endothelial dysfunction and oxidative stress do not serve roles in the pathogenesis of CRC. The dilatory mechanisms of NO and H2S in mesenteric arteries of patients with CRC were K+ channel- and time-dependent, and the activity of cystathionine γ-lyase enzyme inhibited the ability of exogenous NO in vasodilation processes.
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Affiliation(s)
- Awat Y Hassan
- Department of Biology, College of Science, Salahaddin University-Erbil, Erbil, Kurdistan Region 44001, Iraq
| | - Ismail M Maulood
- Department of Biology, College of Science, Salahaddin University-Erbil, Erbil, Kurdistan Region 44001, Iraq
| | - Abbas Salihi
- Department of Biology, College of Science, Salahaddin University-Erbil, Erbil, Kurdistan Region 44001, Iraq.,Department of Medical Analysis, Faculty of Science, Tishk International University, Erbil, Kurdistan Region 44001, Iraq
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Reina-Torres E, De Ieso ML, Pasquale LR, Madekurozwa M, van Batenburg-Sherwood J, Overby DR, Stamer WD. The vital role for nitric oxide in intraocular pressure homeostasis. Prog Retin Eye Res 2020; 83:100922. [PMID: 33253900 DOI: 10.1016/j.preteyeres.2020.100922] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 11/13/2020] [Accepted: 11/23/2020] [Indexed: 02/07/2023]
Abstract
Catalyzed by endothelial nitric oxide (NO) synthase (eNOS) activity, NO is a gaseous signaling molecule maintaining endothelial and cardiovascular homeostasis. Principally, NO regulates the contractility of vascular smooth muscle cells and permeability of endothelial cells in response to either biochemical or biomechanical cues. In the conventional outflow pathway of the eye, the smooth muscle-like trabecular meshwork (TM) cells and Schlemm's canal (SC) endothelium control aqueous humor outflow resistance, and therefore intraocular pressure (IOP). The mechanisms by which outflow resistance is regulated are complicated, but NO appears to be a key player as enhancement or inhibition of NO signaling dramatically affects outflow function; and polymorphisms in NOS3, the gene that encodes eNOS modifies the relation between various environmental exposures and glaucoma. Based upon a comprehensive review of past foundational studies, we present a model whereby NO controls a feedback signaling loop in the conventional outflow pathway that is sensitive to changes in IOP and its oscillations. Thus, upon IOP elevation, the outflow pathway tissues distend, and the SC lumen narrows resulting in increased SC endothelial shear stress and stretch. In response, SC cells upregulate the production of NO, relaxing neighboring TM cells and increasing permeability of SC's inner wall. These IOP-dependent changes in the outflow pathway tissues reduce the resistance to aqueous humor drainage and lower IOP, which, in turn, diminishes the biomechanical signaling on SC. Similar to cardiovascular pathogenesis, dysregulation of the eNOS/NO system leads to dysfunctional outflow regulation and ocular hypertension, eventually resulting in primary open-angle glaucoma.
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Affiliation(s)
| | | | - Louis R Pasquale
- Eye and Vision Research Institute of New York Eye and Ear Infirmary at Mount Sinai, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | | | | | - Darryl R Overby
- Department of Bioengineering, Imperial College London, London, UK.
| | - W Daniel Stamer
- Department of Ophthalmology, Duke University, Durham, NC, USA.
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Prostanoids contribute to regulation of inwardly rectifying K + channels in intrarenal arterial smooth muscle cells. Life Sci 2020; 250:117586. [PMID: 32222464 DOI: 10.1016/j.lfs.2020.117586] [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: 11/24/2019] [Revised: 03/19/2020] [Accepted: 03/19/2020] [Indexed: 11/23/2022]
Abstract
AIM The inward rectifier K+ (Kir) channels and prostanoids are important factors in regulating vascular tone, but the relationship between them has not been well studied. We aimed to study the involvement of prostanoids in regulating Kir activity in the rat intrarenal arteries (RIRAs). MAIN METHODS The vascular tone of isolated RIRAs was recorded with a wire myograph. The intracellular Ca2+ concentrations ([Ca2+]i) and Kir currents were measured with a Ca2+-sensitive fluorescence probe and patch clamp, respectively, in the arterial smooth muscle cell (ASMC) freshly isolated from RIRAs. Kir2.1 expression in RIRAs was assayed by Western blotting. KEY FINDINGS At 0.03-1.0 mM, BaCl2 (a specific Kir blocker) concentration-dependently contracted RIRAs and elevated [Ca2+]i levels. Mild stimulations with various vasoconstrictors at low concentrations significantly potentiated RIRA contraction induced by Kir closure with BaCl2. In both the quiescent and the stimulated RIRAs, cyclooxygenase inhibition and thromboxane-prostanoid receptor (TPR) antagonism depressed BaCl2-induced RIRA contraction, while nitric oxide (NO) synthetase inhibition and endothelium-denudation enhanced the contraction. Kir2.1 expression was significantly more abundant in smaller RIRAs. Ba2+-sensitive Kir currents were depressed by TPR agonist U46619 while increased by NO donor sodium nitroprusside. SIGNIFICANCE The present results reveal that vasoconstrictor stimulation augments RIRA contraction induced by Kir closure with Ba+ and indicate that prostanoid synthesis followed by TPR activation is involved in the modulation of the myocyte Kir activity. This study suggests that prostanoid synthesis and TPR may be potential targets for dysfunctions in renal blood circulation.
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Manoury B, Idres S, Leblais V, Fischmeister R. Ion channels as effectors of cyclic nucleotide pathways: Functional relevance for arterial tone regulation. Pharmacol Ther 2020; 209:107499. [PMID: 32068004 DOI: 10.1016/j.pharmthera.2020.107499] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Accepted: 02/05/2020] [Indexed: 02/07/2023]
Abstract
Numerous mediators and drugs regulate blood flow or arterial pressure by acting on vascular tone, involving cyclic nucleotide intracellular pathways. These signals lead to regulation of several cellular effectors, including ion channels that tune cell membrane potential, Ca2+ influx and vascular tone. The characterization of these vasocontrictive or vasodilating mechanisms has grown in complexity due to i) the variety of ion channels that are expressed in both vascular endothelial and smooth muscle cells, ii) the heterogeneity of responses among the various vascular beds, and iii) the number of molecular mechanisms involved in cyclic nucleotide signalling in health and disease. This review synthesizes key data from literature that highlight ion channels as physiologically relevant effectors of cyclic nucleotide pathways in the vasculature, including the characterization of the molecular mechanisms involved. In smooth muscle cells, cation influx or chloride efflux through ion channels are associated with vasoconstriction, whereas K+ efflux repolarizes the cell membrane potential and mediates vasodilatation. Both categories of ion currents are under the influence of cAMP and cGMP pathways. Evidence that some ion channels are influenced by CN signalling in endothelial cells will also be presented. Emphasis will also be put on recent data touching a variety of determinants such as phosphodiesterases, EPAC and kinase anchoring, that complicate or even challenge former paradigms.
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Affiliation(s)
- Boris Manoury
- Inserm, Umr-S 1180, Université Paris-Saclay, Châtenay-Malabry, France.
| | - Sarah Idres
- Inserm, Umr-S 1180, Université Paris-Saclay, Châtenay-Malabry, France
| | - Véronique Leblais
- Inserm, Umr-S 1180, Université Paris-Saclay, Châtenay-Malabry, France
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Shvetsova AA, Gaynullina DK, Tarasova OS, Schubert R. Negative feedback regulation of vasocontraction by potassium channels in 10- to 15-day-old rats: Dominating role of K v 7 channels. Acta Physiol (Oxf) 2019; 225:e13176. [PMID: 30136434 DOI: 10.1111/apha.13176] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 08/11/2018] [Accepted: 08/20/2018] [Indexed: 12/26/2022]
Abstract
AIM Potassium channels are key regulators of smooth muscle membrane potential and arterial tone. However, the roles of potassium channels in vascular tone regulation in the systemic circulation during early postnatal development are poorly understood. Therefore, this study tested the hypothesis that the negative feedback regulation of vasocontraction by potassium channels changes during maturation. METHODS Experiments were performed on endothelium-denuded saphenous arteries from 10- to 15-day-old and 2- to 3-month-old male rats. Isometric force and membrane potential were recorded using wire myography and the sharp microelectrode technique respectively; mRNA and protein contents were determined by qPCR and Western blotting. RESULTS The effects of Kv 1, Kir and Kv 7 channel blockers (DPO-1, BaCl2 , XE991) on methoxamine-induced contraction were larger in arteries of 10- to 15-day-old compared to 2- to 3-month-old animals. In contrast, the BKC a channel blocker iberiotoxin had a stronger influence in 2- to 3- month-old rats. The effects of KATP and Kv 2 channel blockers (glibenclamide, stromatoxin) were not pronounced at both ages. The larger influence of Kv 7 and Kir channel blockade on arterial contraction in 10- to 15-day-old rats was associated with more prominent smooth muscle depolarization. The developmental alterations in potassium channel functioning were generally consistent with their mRNA and protein expression levels in arterial smooth muscle. CONCLUSION The negative feedback regulation of vasocontraction by potassium channels varies during maturation depending on the channel type. A dominating contribution of Kv 7 channels to the regulation of basal tone and agonist-induced contraction was observed in arteries of 10- to 15-day-old animals.
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Affiliation(s)
- Anastasia A. Shvetsova
- Centre for Biomedicine and Medical Technology Mannheim (CBTM); European Center of Angioscience (ECAS); Research Division Cardiovascular Physiology; Medical Faculty Mannheim; Heidelberg University; Heidelberg Germany
- Faculty of Biology; M.V. Lomonosov Moscow State University; Moscow Russia
- State Research Center of the Russian Federation - Institute for Biomedical Problems; Russian Academy of Sciences; Moscow Russia
| | - Dina K. Gaynullina
- Faculty of Biology; M.V. Lomonosov Moscow State University; Moscow Russia
- State Research Center of the Russian Federation - Institute for Biomedical Problems; Russian Academy of Sciences; Moscow Russia
- Department of Physiology; Russian National Research Medical University; Moscow Russia
| | - Olga S. Tarasova
- Faculty of Biology; M.V. Lomonosov Moscow State University; Moscow Russia
- State Research Center of the Russian Federation - Institute for Biomedical Problems; Russian Academy of Sciences; Moscow Russia
| | - Rudolf Schubert
- Centre for Biomedicine and Medical Technology Mannheim (CBTM); European Center of Angioscience (ECAS); Research Division Cardiovascular Physiology; Medical Faculty Mannheim; Heidelberg University; Heidelberg Germany
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Hearon CM, Richards JC, Racine ML, Luckasen GJ, Larson DG, Dinenno FA. Amplification of endothelium-dependent vasodilatation in contracting human skeletal muscle: role of K IR channels. J Physiol 2018; 597:1321-1335. [PMID: 30506579 DOI: 10.1113/jp276998] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 11/29/2018] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS In humans, the vasodilatory response to skeletal muscle contraction is mediated in part by activation of inwardly rectifying potassium (KIR ) channels. Evidence from animal models suggest that KIR channels serve as electrical amplifiers of endothelium-dependent hyperpolarization (EDH). We found that skeletal muscle contraction amplifies vasodilatation to the endothelium-dependent agonist ACh, whereas there was no change in the vasodilatory response to sodium nitroprusside, an endothelium-independent nitric oxide donor. Blockade of KIR channels reduced the exercise-induced amplification of ACh-mediated vasodilatation. Conversely, pharmacological activation of KIR channels in quiescent muscle via intra-arterial infusion of KCl independently amplified the vasodilatory response to ACh. This study is the first in humans to demonstrate that specific endothelium-dependent vasodilatory signalling is amplified in the vasculature of contracting skeletal muscle and that KIR channels may serve as amplifiers of EDH-like vasodilatory signalling in humans. ABSTRACT The local vasodilatory response to muscle contraction is due in part to the activation of inwardly rectifying potassium (KIR ) channels. Evidence from animal models suggest that KIR channels function as 'amplifiers' of endothelium-dependent vasodilators. We tested the hypothesis that contracting muscle selectively amplifies endothelium-dependent vasodilatation via activation of KIR channels. We measured forearm blood flow (Doppler ultrasound) and calculated changes in vascular conductance (FVC) to local intra-arterial infusion of ACh (endothelium-dependent dilator) during resting conditions, handgrip exercise (5% maximum voluntary contraction) or sodium nitroprusside (SNP; endothelium-independent dilator) which served as a high-flow control condition (n = 7, young healthy men and women). Trials were performed before and after blockade of KIR channels via infusion of barium chloride. Exercise augmented peak ACh-mediated vasodilatation (ΔFVC saline: 117 ± 14; exercise: 236 ± 21 ml min-1 (100 mmHg)-1 ; P < 0.05), whereas SNP did not impact ACh-mediated vasodilatation. Blockade of KIR channels attenuated the exercise-induced augmentation of ACh. In eight additional subjects, SNP was administered as the experimental dilator. In contrast to ACh, exercise did not alter SNP-mediated vasodilatation (ΔFVC saline: 158 ± 35; exercise: 121 ± 22 ml min-1 (100 mmHg)-1 ; n.s.). Finally, in a subset of six subjects, direct pharmacological activation of KIR channels in quiescent muscle via infusion of KCl amplified peak ACh-mediated vasodilatation (ΔFVC saline: 97 ± 15, KCl: 142 ± 16 ml min-1 (100 mmHg)-1 ; respectively; P < 0.05). These findings indicate that skeletal muscle contractions selectively amplify endothelium-dependent vasodilatory signalling via activation of KIR channels, and this may be an important mechanism contributing to the normal vasodilatory response to exercise in humans.
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Affiliation(s)
- Christopher M Hearon
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Jennifer C Richards
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Mathew L Racine
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Gary J Luckasen
- Medical Center of the Rockies Foundation, University of Colorado Health, Loveland, CO, USA
| | - Dennis G Larson
- Medical Center of the Rockies Foundation, University of Colorado Health, Loveland, CO, USA
| | - Frank A Dinenno
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA.,Center for Cardiovascular Research, Colorado State University, Fort Collins, CO, 80523, USA
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Reyes RV, Díaz M, Ebensperger G, Herrera EA, Quezada SA, Hernandez I, Sanhueza EM, Parer JT, Giussani DA, Llanos AJ. The role of nitric oxide in the cardiopulmonary response to hypoxia in highland and lowland newborn llamas. J Physiol 2018; 596:5907-5923. [PMID: 29369354 PMCID: PMC6265547 DOI: 10.1113/jp274340] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 01/17/2018] [Indexed: 01/19/2023] Open
Abstract
KEY POINTS Perinatal hypoxia causes pulmonary hypertension in neonates, including humans. However, in species adapted to hypoxia, such as the llama, there is protection against pulmonary hypertension. Nitric oxide (NO) is a vasodilatator with an established role in the cardiopulmonary system of many species, but its function in the hypoxic pulmonary vasoconstrictor response in the newborn llama is unknown. Therefore, we studied the role of NO in the cardiopulmonary responses to acute hypoxia in high- and lowland newborn llamas. We show that high- compared to lowland newborn llamas have a reduced pulmonary vasoconstrictor response to acute hypoxia. Protection against excessive pulmonary vasoconstriction in the highland llama is mediated via enhancement of NO pathways, including increased MYPT1 and reduced ROCK expression as well as Ca2+ desensitization. Blunting of pulmonary hypertensive responses to hypoxia through enhanced NO pathways may be an adaptive mechanism to withstand life at high altitude in the newborn llama. ABSTRACT Llamas are born in the Alto Andino with protection against pulmonary hypertension. The physiology underlying protection against pulmonary vasoconstrictor responses to acute hypoxia in highland species is unknown. We determined the role of nitric oxide (NO) in the cardiopulmonary responses to acute hypoxia in high- and lowland newborn llamas. The cardiopulmonary function of newborn llamas born at low (580 m) or high altitude (3600 m) was studied under acute hypoxia, with and without NO blockade. In pulmonary arteries, we measured the reactivity to potassium and sodium nitroprusside (SNP), and in lung we determined the content of cGMP and the expression of the NO-related proteins: BKCa, PDE5, PSer92-PDE5, PKG-1, ROCK1 and 2, MYPT1, PSer695-MYPT1, PThr696-MYPT1, MLC20 and PSer19-MLC20. Pulmonary vascular remodelling was evaluated by morphometry and based on α-actin expression. High- compared to lowland newborn llamas showed lower in vivo pulmonary arterial pressor responses to acute hypoxia. This protection involved enhanced NO function, as NO blockade reverted the effect and the pulmonary arterial dilatator response to SNP was significantly enhanced in highland neonates. The pulmonary expression of ROCK2 and the phosphorylation of MLC20 were lower in high-altitude llamas. Conversely, MYPT1 was up-regulated whilst PSer695-MYPT1 and PThr695-MYPT1 did not change. Enhanced NO-dependent mechanisms were insufficient to prevent pulmonary arterial remodelling. Combined, the data strongly support that in the highland newborn llama reduced ROCK, increased MYPT1 expression and Ca2+ desensitization in pulmonary tissue allow an enhanced NO biology to limit hypoxic pulmonary constrictor responses. Blunting of hypoxic pulmonary hypertensive responses may be an adaptive mechanism to life at high altitude.
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Affiliation(s)
- Roberto V. Reyes
- Laboratorio de Bioquímica y Biología Molecular de la Hipoxia, Programa de Fisiopatología, Instituto de Ciencias Biomédicas, Facultad de MedicinaUniversidad de ChileSantiagoChile
- International Center for Andean Studies (INCAS)Universidad de ChileSantiagoChile
| | - Marcela Díaz
- Departamento de Promoción de la Salud de la Mujer y el Recién Nacido, Facultad de MedicinaUniversidad de ChileSantiagoChile
- Laboratorio de Mecanismos de Stress y Adaptación Vascular, Programa de Fisiopatología, Instituto de Ciencias Biomédicas, Facultad de MedicinaUniversidad de ChileSantiagoChile
| | - Germán Ebensperger
- Laboratorio de Mecanismos de Stress y Adaptación Vascular, Programa de Fisiopatología, Instituto de Ciencias Biomédicas, Facultad de MedicinaUniversidad de ChileSantiagoChile
| | - Emilio A. Herrera
- International Center for Andean Studies (INCAS)Universidad de ChileSantiagoChile
- Laboratorio de Función y Reactividad Vascular, Programa de Fisiopatología, Instituto de Ciencias Biomédicas, Facultad de MedicinaUniversidad de ChileSantiagoChile
| | - Sebastián A. Quezada
- Laboratorio de Bioquímica y Biología Molecular de la Hipoxia, Programa de Fisiopatología, Instituto de Ciencias Biomédicas, Facultad de MedicinaUniversidad de ChileSantiagoChile
| | - Ismael Hernandez
- Laboratorio de Bioquímica y Biología Molecular de la Hipoxia, Programa de Fisiopatología, Instituto de Ciencias Biomédicas, Facultad de MedicinaUniversidad de ChileSantiagoChile
| | - Emilia M. Sanhueza
- Laboratorio de Fisiología y Fisiopatología del Desarrollo, Programa de Fisiopatología, Instituto de Ciencias Biomédicas, Facultad de MedicinaUniversidad de ChileSantiagoChile
| | - Julian T. Parer
- Department of Obstetrics, Gynecology and Reproductive SciencesUniversity of California San FranciscoCaliforniaUSA
| | - Dino A. Giussani
- Department of Physiology, Development and NeuroscienceUniversity of CambridgeUK
| | - Aníbal J. Llanos
- International Center for Andean Studies (INCAS)Universidad de ChileSantiagoChile
- Laboratorio de Fisiología y Fisiopatología del Desarrollo, Programa de Fisiopatología, Instituto de Ciencias Biomédicas, Facultad de MedicinaUniversidad de ChileSantiagoChile
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11
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Gollasch M, Welsh DG, Schubert R. Perivascular adipose tissue and the dynamic regulation of K v 7 and K ir channels: Implications for resistant hypertension. Microcirculation 2018; 25. [PMID: 29211322 DOI: 10.1111/micc.12434] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 11/30/2017] [Indexed: 12/20/2022]
Abstract
Resistant hypertension is defined as high blood pressure that remains uncontrolled despite treatment with at least three antihypertensive drugs at adequate doses. Resistant hypertension is an increasingly common clinical problem in older age, obesity, diabetes, sleep apnea, and chronic kidney disease. Although the direct vasodilator minoxidil was introduced in the early 1970s, only recently has this drug been shown to be particularly effective in a subgroup of patients with treatment-resistant or uncontrolled hypertension. This pharmacological approach is interesting from a mechanistic perspective as minoxidil is the only clinically used K+ channel opener today, which targets a subclass of K+ channels, namely KATP channels in VSMCs. Beside KATP channels, two other classes of VSMC K+ channels could represent novel effective targets for treatment of resistant hypertension, namely Kv 7 (KCNQ) and inward rectifier potassium (Kir 2.1) channels. Interestingly, these channels are unique among VSMC potassium channels. First, both have been implicated in the control of microvascular tone by perivascular adipose tissue. Second, they exhibit biophysical properties strongly controlled and regulated by membrane voltage, but not intracellular calcium. This review focuses on Kv 7 (Kv 7.1-5) and Kir (Kir 2.1) channels in VSMCs as potential novel drug targets for treatment of resistant hypertension, particularly in comorbid conditions such as obesity and metabolic syndrome.
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Affiliation(s)
- Maik Gollasch
- Medical Clinic for Nephrology and Internal Intensive Care, Charité Campus Virchow Klinikum, Experimental and Clinical Research Center (ECRC) - a joint cooperation between the Charité - University Medicine Berlin and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Donald G Welsh
- Department of Physiology and Pharmacology, Western University, London, ON, Canada
| | - Rudolf Schubert
- Centre for Biomedicine and Medical Technology Mannheim (CBTM), Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
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12
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Schmid J, Müller B, Heppeler D, Gaynullina D, Kassmann M, Gagov H, Mladenov M, Gollasch M, Schubert R. The Unexpected Role of Calcium-Activated Potassium Channels: Limitation of NO-Induced Arterial Relaxation. J Am Heart Assoc 2018; 7:e007808. [PMID: 29574460 PMCID: PMC5907584 DOI: 10.1161/jaha.117.007808] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 02/14/2018] [Indexed: 11/24/2022]
Abstract
BACKGROUND Multiple studies have shown that an NO-induced activation of vascular smooth muscle BK channels contributes to the NO-evoked dilation in many blood vessels. In vivo, NO is released continuously. NO attenuates vessel constrictions and, therefore, exerts an anticontractile effect. It is unknown whether the anticontractile effect of continuously present NO is mediated by BK channels. METHODS AND RESULTS This study tested the hypothesis that BK channels mediate the vasodilatory effect of continuously present NO. Experiments were performed on rat and mouse tail and rat saphenous arteries using isometric myography and FURA-2 fluorimetry. Continuously present NO donors, as well as endogenous NO, attenuated methoxamine-induced vasoconstrictions. This effect was augmented in the presence of the BK channel blocker iberiotoxin. Moreover, the contractile effect of iberiotoxin was reduced in the presence of NO donors. The effect of the NO donor sodium nitroprusside was abolished by an NO scavenger and by a guanylyl cyclase inhibitor. In addition, the effect of sodium nitroprusside was reduced considerably by a protein kinase G inhibitor, but was not altered by inhibition of H2S generation. Sodium nitroprusside attenuated the intracellular calcium concentration response to methoxamine. Furthermore, sodium nitroprusside strongly reduced methoxamine-induced calcium influx, which depends entirely on L-type calcium channels. It did not affect methoxamine-induced calcium release. CONCLUSIONS In summary, this study demonstrates the following: (1) continuously present NO evokes a strong anticontractile effect on rat and mouse arteries; (2) the iberiotoxin-induced augmentation of the effect of NO is associated with an NO-induced reduction of the effect of iberiotoxin; and (3) NO evoked a reduction of calcium influx via L-type calcium channels.
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Affiliation(s)
- Johannes Schmid
- Centre for Biomedicine and Medical Technology Mannheim and European Center of Angioscience, Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Bettina Müller
- Centre for Biomedicine and Medical Technology Mannheim and European Center of Angioscience, Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - David Heppeler
- Centre for Biomedicine and Medical Technology Mannheim and European Center of Angioscience, Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Dina Gaynullina
- Centre for Biomedicine and Medical Technology Mannheim and European Center of Angioscience, Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Faculty of Biology, M.V. Lomonosov, Moscow State University, Moscow, Russia
- Department of Physiology, Russian National Research Medical University, Moscow, Russia
| | - Mario Kassmann
- Experimental and Clinical Research Center, a joint cooperation between the, Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Hristo Gagov
- Centre for Biomedicine and Medical Technology Mannheim and European Center of Angioscience, Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Mitko Mladenov
- Centre for Biomedicine and Medical Technology Mannheim and European Center of Angioscience, Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Maik Gollasch
- Experimental and Clinical Research Center, a joint cooperation between the, Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Rudolf Schubert
- Centre for Biomedicine and Medical Technology Mannheim and European Center of Angioscience, Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
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13
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Jackson WF. Boosting the signal: Endothelial inward rectifier K + channels. Microcirculation 2018; 24. [PMID: 27652592 DOI: 10.1111/micc.12319] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 09/12/2016] [Indexed: 12/19/2022]
Abstract
Endothelial cells express a diverse array of ion channels including members of the strong inward rectifier family composed of KIR 2 subunits. These two-membrane spanning domain channels are modulated by their lipid environment, and exist in macromolecular signaling complexes with receptors, protein kinases and other ion channels. Inward rectifier K+ channel (KIR ) currents display a region of negative slope conductance at membrane potentials positive to the K+ equilibrium potential that allows outward current through the channels to be activated by membrane hyperpolarization, permitting KIR to amplify hyperpolarization induced by other K+ channels and ion transporters. Increases in extracellular K+ concentration activate KIR allowing them to sense extracellular K+ concentration and transduce this change into membrane hyperpolarization. These properties position KIR to participate in the mechanism of action of hyperpolarizing vasodilators and contribute to cell-cell conduction of hyperpolarization along the wall of microvessels. The expression of KIR in capillaries in electrically active tissues may allow KIR to sense extracellular K+ , contributing to functional hyperemia. Understanding the regulation of expression and function of microvascular endothelial KIR will improve our understanding of the control of blood flow in the microcirculation in health and disease and may provide new targets for the development of therapeutics in the future.
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Affiliation(s)
- William F Jackson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, USA
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14
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Gheibi S, Jeddi S, Kashfi K, Ghasemi A. Regulation of vascular tone homeostasis by NO and H 2S: Implications in hypertension. Biochem Pharmacol 2018; 149:42-59. [PMID: 29330066 PMCID: PMC5866223 DOI: 10.1016/j.bcp.2018.01.017] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 01/05/2018] [Indexed: 02/09/2023]
Abstract
Nitric oxide (NO) and hydrogen sulfide (H2S) are two gasotransmitters that are produced in the vasculature and contribute to the regulation of vascular tone. NO and H2S are synthesized in both vascular smooth muscle and endothelial cells; NO functions primarily through the sGC/cGMP pathway, and H2S mainly through activation of the ATP-dependent potassium channels; both leading to relaxation of vascular smooth muscle cells. A deficit in the NO/H2S homeostasis is involved in the pathogenesis of various cardiovascular diseases, especially hypertension. It is now becoming increasingly clear that there are important interactions between NO and H2S and that have a profound impact on vascular tone and this may provide insights into the new therapeutic interventions. The aim of this review is to provide a better understanding of individual and interactive roles of NO and H2S in vascular biology. Overall, available data indicate that both NO and H2S contribute to vascular (patho)physiology and in regulating blood pressure. In addition, boosting NO and H2S using various dietary sources or donors could be a hopeful therapeutic strategy in the management of hypertension.
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Affiliation(s)
- Sevda Gheibi
- Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Neurophysiology Research Center and Department of Physiology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Sajad Jeddi
- Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Khosrow Kashfi
- Department of Molecular, Cellular and Biomedical Sciences, Sophie Davis School of Biomedical Education, City University of New York School of Medicine, NY, USA
| | - Asghar Ghasemi
- Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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15
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Tykocki NR, Boerman EM, Jackson WF. Smooth Muscle Ion Channels and Regulation of Vascular Tone in Resistance Arteries and Arterioles. Compr Physiol 2017; 7:485-581. [PMID: 28333380 DOI: 10.1002/cphy.c160011] [Citation(s) in RCA: 222] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Vascular tone of resistance arteries and arterioles determines peripheral vascular resistance, contributing to the regulation of blood pressure and blood flow to, and within the body's tissues and organs. Ion channels in the plasma membrane and endoplasmic reticulum of vascular smooth muscle cells (SMCs) in these blood vessels importantly contribute to the regulation of intracellular Ca2+ concentration, the primary determinant of SMC contractile activity and vascular tone. Ion channels provide the main source of activator Ca2+ that determines vascular tone, and strongly contribute to setting and regulating membrane potential, which, in turn, regulates the open-state-probability of voltage gated Ca2+ channels (VGCCs), the primary source of Ca2+ in resistance artery and arteriolar SMCs. Ion channel function is also modulated by vasoconstrictors and vasodilators, contributing to all aspects of the regulation of vascular tone. This review will focus on the physiology of VGCCs, voltage-gated K+ (KV) channels, large-conductance Ca2+-activated K+ (BKCa) channels, strong-inward-rectifier K+ (KIR) channels, ATP-sensitive K+ (KATP) channels, ryanodine receptors (RyRs), inositol 1,4,5-trisphosphate receptors (IP3Rs), and a variety of transient receptor potential (TRP) channels that contribute to pressure-induced myogenic tone in resistance arteries and arterioles, the modulation of the function of these ion channels by vasoconstrictors and vasodilators, their role in the functional regulation of tissue blood flow and their dysfunction in diseases such as hypertension, obesity, and diabetes. © 2017 American Physiological Society. Compr Physiol 7:485-581, 2017.
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Affiliation(s)
- Nathan R Tykocki
- Department of Pharmacology, University of Vermont, Burlington, Vermont, USA
| | - Erika M Boerman
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri, USA
| | - William F Jackson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan, USA
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16
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17
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El-Mas MM, El-Gowilly SM, Elsalakawy LK, El-Gowelli HM. Oestrogen compromises the facilitatory effect of chronic nicotine on adenosine A2Breceptor-K+channel-mediated renal vasodilation. Clin Exp Pharmacol Physiol 2014; 41:600-7. [DOI: 10.1111/1440-1681.12255] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 04/20/2014] [Accepted: 05/05/2014] [Indexed: 01/15/2023]
Affiliation(s)
- Mahmoud M El-Mas
- Department of Pharmacology and Toxicology; Faculty of Pharmacy; Alexandria University; Alexandria Egypt
| | - Sahar M El-Gowilly
- Department of Pharmacology and Toxicology; Faculty of Pharmacy; Alexandria University; Alexandria Egypt
| | - Lamia K Elsalakawy
- Department of Pharmacology and Toxicology; Faculty of Pharmacy; Alexandria University; Alexandria Egypt
| | - Hanan M El-Gowelli
- Department of Pharmacology and Toxicology; Faculty of Pharmacy; Alexandria University; Alexandria Egypt
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18
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Sheng J, Shim W, Lu J, Lim SY, Ong BH, Lim TS, Liew R, Chua YL, Wong P. Electrophysiology of human cardiac atrial and ventricular telocytes. J Cell Mol Med 2014; 18:355-62. [PMID: 24467431 PMCID: PMC3930421 DOI: 10.1111/jcmm.12240] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 12/24/2013] [Indexed: 01/13/2023] Open
Abstract
Telocytes (TCs) with exceptionally long cellular processes of telopodes have been described in human epicardium to act as structural supporting cells in the heart. We examined myocardial chamber-specific TCs identified in atrial and ventricular fibroblast culture using immunocytochemistry and studied their electrophysiological property by whole-cell patch clamp. Atrial and ventricular TCs with extended telopodes and alternating podoms and podomers that expressed CD34, c-Kit and PDGFR-β were identified. These cells expressed large conductance Ca2+-activated K+ current (BKCa) and inwardly rectifying K+ current (IKir), but not transient outward K+ current (Ito) and ATP-sensitive potassium current (KATP). The active channels were functionally competent with demonstrated modulatory response to H2S and transforming growth factor (TGF)-β1 whereby H2S significantly inhibited the stimulatory effect of TGF-β1 on current density of both BKCa and IKir. Furthermore, H2S attenuated TGF-β1-stimulated KCa1.1/Kv1.1 (encode BKCa) and Kir2.1 (encode IKir) expression in TCs. Our results show that functionally competent K+ channels are present in human atrial and ventricular TCs and their modulation may have significant implications in myocardial physiopathology.
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Affiliation(s)
- Jingwei Sheng
- Research and Development Unit, National Heart Centre Singapore, Singapore
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19
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Fouda MA, El-Gowelli HM, El-Gowilly SM, Rashed L, El-Mas MM. Impairment of nitric oxide synthase but not heme oxygenase accounts for baroreflex dysfunction caused by chronic nicotine in female rats. PLoS One 2014; 9:e98681. [PMID: 24870610 PMCID: PMC4037226 DOI: 10.1371/journal.pone.0098681] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 05/07/2014] [Indexed: 12/31/2022] Open
Abstract
We recently reported that chronic nicotine impairs reflex chronotropic activity in female rats. Here, we sought evidence to implicate nitric oxide synthase (NOS) and/or heme oxygenase (HO) in the nicotine-baroreflex interaction. Baroreflex curves relating changes in heart rate to increases (phenylephrine) or decreases (sodium nitroprusside) in blood pressure were generated in conscious female rats treated with nicotine or saline in absence and presence of pharmacological modulators of NOS or HO activity. Compared with saline-treated rats, nicotine (2 mg/kg/day i.p., for 14 days) significantly reduced the slopes of baroreflex curves, a measure of baroreflex sensitivity (BRS). Findings that favor the involvement of NOS inhibition in the nicotine effect were (i) NOS inhibition (Nω-Nitro-L-arginine methyl ester, L-NAME) reduced BRS in control rats but failed to do so in nicotine-treated rats, (ii) L-arginine, NO donor, reversed the BRS inhibitory effect of nicotine. Alternatively, HO inhibition (zinc protoporphyrin IX, ZnPP) had no effect on BRS in nicotine- or control rats and failed to reverse the beneficial effect of L-arginine on nicotine-BRS interaction. Similar to female rats, BRS was reduced by L-NAME, but not ZnPP, in male rats and the L-NAME effect was not accentuated after concomitant administration of nicotine. Baroreflex dysfunction caused by nicotine in female rats was blunted after supplementation with hemin (HO inducer) but not tricarbonyldichlororuthenium(II) dimer (CORM-2), a carbon monoxide (CO) releasing molecule, or bilirubin, the breakdown product of heme catabolism. The facilitatory effect of hemin was abolished upon simultaneous treatment with L-NAME or 1H-[1], [2], [4] oxadiazolo[4,3-a] quinoxalin-1-one (inhibitor of soluble guanylate cyclase, sGC). The activities of HO and NOS in brainstem tissues were also significantly increased by hemin. Thus, the inhibition of NOS, but not HO, accounts for the baroreflex depressant of chronic nicotine. Further, hemin alleviates the nicotine effect through a mechanism that is NOS/sGC but not CO or bilirubin-dependent.
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Affiliation(s)
- Mohamed A. Fouda
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Hanan M. El-Gowelli
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Sahar M. El-Gowilly
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Laila Rashed
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Mahmoud M. El-Mas
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
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20
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Subedi H, Hassanin HA, Brasch NE. Kinetic and Mechanistic Studies on the Reaction of the Vitamin B12 Complex Aquacobalamin with the HNO Donor Angeli’s Salt: Angeli’s Salt and HNO React with Aquacobalamin. Inorg Chem 2014; 53:1570-7. [DOI: 10.1021/ic402613z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
| | - Hanaa A. Hassanin
- Department
of Chemistry, Ain Shams University, Abbassia Square, Cairo, 11566, Egypt
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21
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Queiroz TM, Mendes-Júnior LG, Guimarães DD, França-Silva MS, Nalivaiko E, Braga VA. Cardiorespiratory effects induced by 2-nitrate-1,3-dibuthoxypropan are reduced by nitric oxide scavenger in rats. Auton Neurosci 2013; 181:31-6. [PMID: 24418115 DOI: 10.1016/j.autneu.2013.12.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 12/13/2013] [Accepted: 12/17/2013] [Indexed: 11/26/2022]
Abstract
The search for new nitric oxide donors is warranted by the limitations of organic nitrates currently used in cardiology. The new organic nitrate 2-nitrate-1,3-dibuthoxypropan (NDBP) exhibited promising cardiovascular activities in previous studies. The aim of this study was to investigate the cardiorespiratory responses evoked by NDBP and to compare them to the clinically used organic nitrate nitroglycerine (NTG). Arterial pressure, heart rate and respiration were recorded in conscious adult male Wistar rats. Bolus i.v. injection of NDBP (1 to 15mg/kg; n=8) and NTG (0.1 to 5mg/kg; n=8) produced hypotension. NDBP induced bradycardia at all doses, while NTG induced tachycardia at three lower doses but bradycardia at higher doses. Hydroxocobalamin (20mg/kg; HDX), a NO scavenger, blunted hypotension induced by NDBP (15mg/kg), and its bradycardic effect (n=6). In addition, HDX blunted both hypotension and bradycardia induced by a single dose of NTG (2.5mg/kg; n=6). Both NDBP and NTG altered respiratory rate, inducing a biphasic effect with a bradypnea followed by a tachypnea; HDX attenuated these responses. Our data indicate that NDBP and NTG induce hypotension, bradycardia and bradypnea, which are mediated by nitric oxide release.
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Affiliation(s)
- Thyago M Queiroz
- Biotechnology Center, Federal University of Paraiba, João Pessoa, PB, Brazil
| | | | - Drielle D Guimarães
- Biotechnology Center, Federal University of Paraiba, João Pessoa, PB, Brazil
| | | | - Eugene Nalivaiko
- School of Biomedical Sciences and Pharmacy, University of Newcastle, NSW, Australia.
| | - Valdir A Braga
- Biotechnology Center, Federal University of Paraiba, João Pessoa, PB, Brazil
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22
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Walker DT, Dassanayake RS, Garcia KA, Mukherjee R, Brasch NE. Mechanistic Studies on the Reaction of Nitrocobalamin with Glutathione: Kinetic evidence for formation of an aquacobalamin intermediate. Eur J Inorg Chem 2013; 2013:10.1002/ejic.201300254. [PMID: 24415907 PMCID: PMC3885173 DOI: 10.1002/ejic.201300254] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Indexed: 11/09/2022]
Abstract
The essential but also toxic gaseous signaling molecule nitric oxide is scavenged by the reduced vitamin B12 complex cob(II)alamin. The resulting complex, nitroxylcobalamin (NO--Cbl(III)), is rapidly oxidized to nitrocobalamin (NO2Cbl) in the presence of oxygen; however it is unlikely that nitrocobalamin is itself stable in biological systems. Kinetic studies on the reaction between NO2Cbl and the important intracellular antioxidant, glutathione (GSH), are reported. In this study, a reaction pathway is proposed in which the β-axial ligand of NO2Cbl is first substituted by water to give aquacobalamin (H2OCbl+), which then reacts further with GSH to form glutathionylcobalamin (GSCbl). Independent measurements of the four associated rate constants k1, k-1, k2, and k-2 support the proposed mechanism. These findings provide insight into the fundamental mechanism of ligand substitution reactions of cob(III)alamins with inorganic ligands at the β-axial site.
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Affiliation(s)
- David T. Walker
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA
| | - Rohan S. Dassanayake
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA
| | - Kamille A. Garcia
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA
| | - Riya Mukherjee
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA
| | - Nicola E. Brasch
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA
- School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA
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23
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Wang ZQ, Xu JF, Wang JP, Zhao WJ, Zeng M. Involvement of guanylate cyclase and K+ channels in relaxation evoked by ferulate nitrate in rat aorta artery. J Pharmacol Sci 2013; 118:521-30. [PMID: 22510967 DOI: 10.1254/jphs.11179fp] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
Vasorelaxant properties of N-2-(ferulamidoethyl)-nitrate (ferulate nitrate, FLNT), a newly synthesized nitrate, were compared with those of isosorbide dinitrate, nicorandil, nitroglycerin, and 8-bromoguanosine 3,5-cyclic monophosphate (8-Br-cGMP) in rat aorta pre-contracted by phenylephrine. FLNT produced vasorelaxation in a concentration-dependent manner (0.1 - 100 µM). The degree of relaxation induced by FLNT was similar to that induced by isosorbide dinitrate. In addition, removal of endothelium did not affect the relaxant effect of FLNT. FLNT caused a rightward shift of the cumulative concentration-response curves of phenylephrine and reduced the maximal efficacy of contraction. 1H-[1,2,4]Oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ, 10 µM) and K(+)-channel blockers charybdotoxin (CHT, 0.1 µM) and BaCl(2) (1 µM) reduced the relaxant effect of FLNT in the endothelium-denuded arteries, whereas glibenclamide (1 µM) and 4-aminopyridine (1 mM) failed to influence FLNT-induced vasorelaxation. Furthermore, in the presence of ODQ, both CHT (0.1 µM) and BaCl(2) (1 µM) still significantly reduced the relaxation evoked by FLNT. Pretreatment of vessels with hydroxocobalamin, a nitric oxide scavenger, abolished the FLNT effect. These findings demonstrate that FLNT induces relaxation of the rat aorta rings endothelium-independently. Furthermore, we demonstrated that FLNT-induced vasorelaxation is related to its stimulation of soluble guanylate cyclase and activation of K(+) channels.
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Affiliation(s)
- Zhan-Qing Wang
- Department of Pharmacology, General Hospital of Beijing Military Command, Beijing, China.
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24
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Zeng K, Wu XD, Liu QC, Gao F, Lin CZ. Impact of a novel mutation in the 5'-flanking region of natriuretic peptide precursor B gene on the antihypertensive effects of sodium nitroprusside in patients with hypertension. J Hum Hypertens 2012; 27:271-6. [PMID: 22695938 DOI: 10.1038/jhh.2012.25] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Our aim was to identify the possible mutations of the natriuretic peptide precursor B (NPPB) gene in a family with hereditary hypertension, and determine whether the mutations are associated with the antihypertensive effect of sodium nitroprusside. The subjects included one family with hereditary hypertension, 36 cases of sporadic hypertension and 120 healthy controls. The 5'-flanking sequence of NPPB was amplified with PCR, and the presence of mutations was analyzed by direct sequencing. Patients with hypertension were treated with sodium nitroprusside and blood pressure data and serum B-type natriuretic peptide (BNP) levels were measured. A novel complex mutation in 5'-flanking sequence of the NPPB gene was detected in three patients (II 2, III 2, and III 5) of the hypertension family, which included c.-1195_ -1176 insert 5'-CCTTCTTTCTTTCTTTCTTT-3', c.-1208 T>A, c.-1214 T>C, and c.-1216 T>A. Patients with this mutation were less sensitive to sodium nitroprusside treatment. Sporadic hypertension patients (without NPPB gene mutation) and patients with the c.-1181 T>A point mutation were sensitive to sodium nitroprusside treatment. BNP levels of patients with the complex mutation were significantly lower than that of sporadic hypertension patients and c.-1181 T>A mutation patients before and during the early stage of sodium nitroprusside treatment. The complex mutation of the NPPB gene might be an etiological factor of hereditary malignant hypertension, and it is associated with low sensitivity to the antihypertensive effect of sodium nitroprusside.
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Affiliation(s)
- K Zeng
- Department of Anesthesiology, the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
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Morgado M, Cairrão E, Santos-Silva AJ, Verde I. Cyclic nucleotide-dependent relaxation pathways in vascular smooth muscle. Cell Mol Life Sci 2012; 69:247-66. [PMID: 21947498 PMCID: PMC11115151 DOI: 10.1007/s00018-011-0815-2] [Citation(s) in RCA: 135] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Revised: 08/21/2011] [Accepted: 08/23/2011] [Indexed: 02/07/2023]
Abstract
Vascular smooth muscle tone is controlled by a balance between the cellular signaling pathways that mediate the generation of force (vasoconstriction) and release of force (vasodilation). The initiation of force is associated with increases in intracellular calcium concentrations, activation of myosin light-chain kinase, increases in the phosphorylation of the regulatory myosin light chains, and actin-myosin crossbridge cycling. There are, however, several signaling pathways modulating Ca(2+) mobilization and Ca(2+) sensitivity of the contractile machinery that secondarily regulate the contractile response of vascular smooth muscle to receptor agonists. Among these regulatory mechanisms involved in the physiological regulation of vascular tone are the cyclic nucleotides (cAMP and cGMP), which are considered the main messengers that mediate vasodilation under physiological conditions. At least four distinct mechanisms are currently thought to be involved in the vasodilator effect of cyclic nucleotides and their dependent protein kinases: (1) the decrease in cytosolic calcium concentration ([Ca(2+)]c), (2) the hyperpolarization of the smooth muscle cell membrane potential, (3) the reduction in the sensitivity of the contractile machinery by decreasing the [Ca(2+)]c sensitivity of myosin light-chain phosphorylation, and (4) the reduction in the sensitivity of the contractile machinery by uncoupling contraction from myosin light-chain phosphorylation. This review focuses on each of these mechanisms involved in cyclic nucleotide-dependent relaxation of vascular smooth muscle under physiological conditions.
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Affiliation(s)
- Manuel Morgado
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal
| | - Elisa Cairrão
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal
| | - António José Santos-Silva
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal
| | - Ignacio Verde
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal
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Pereira A, Paulo M, Araújo A, Rodrigues G, Bendhack L. Nitric oxide synthesis and biological functions of nitric oxide released from ruthenium compounds. Braz J Med Biol Res 2011; 44:947-57. [DOI: 10.1590/s0100-879x2011007500084] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Accepted: 06/01/2011] [Indexed: 11/22/2022] Open
Affiliation(s)
| | - M. Paulo
- Universidade de São Paulo, Brasil
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Magnusson L, Sorensen CM, Braunstein TH, Holstein-Rathlou NH, Salomonsson M. Mechanisms of K(+) induced renal vasodilation in normo- and hypertensive rats in vivo. Acta Physiol (Oxf) 2011; 202:703-12. [PMID: 21477070 DOI: 10.1111/j.1748-1716.2011.02304.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIM We investigated the mechanisms behind K(+) -induced renal vasodilation in vivo in normotensive Sprague-Dawley (SD) rats and spontaneously hypertensive rats (SHR). METHODS Renal blood flow (RBF) was measured utilizing an ultrasonic Doppler flow probe. Renal vascular resistance (RVR) was calculated as the ratio of mean arterial pressure (MAP) and RBF (RVR = MAP/RBF). Test drugs were introduced directly into the renal artery. Inward rectifier K(+) (K(ir) ) channels and Na(+) ,K(+) -ATPase were blocked by Ba(2+) and ouabain (estimated plasma concentrations ∼20 and ∼7 μm) respectively. RESULTS Confocal immunofluorescence microscopy demonstrated K(ir) 2.1 channels in pre-glomerular vessels of SD and SHR. Ba(2+) caused a transient (6-13%) increase in baseline RVR in both SD and SHR. Ouabain had a similar effect. Elevated renal plasma [K(+) ] (∼12 mm) caused a small and sustained decrease (5-13%) in RVR in both strains. This decrease was significantly larger in SHR than in SD. The K(+) -induced vasodilation was attenuated by Ba(2+) in control SD and SHR and by ouabain in SD. Nitric oxide (NO) blockade using l-NAME treatment increased MAP and decreased RBF in both rat strains, but did not affect the K(+) -induced renal vasodilation. CONCLUSION K(+) -induced renal vasodilation is larger in SHR, mediated by K(ir) channels in SD and SHR, and in addition, by Na(+) ,K(+) -ATPase in SD. In addition, NO is not essential for K(+) -induced renal vasodilation.
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Affiliation(s)
- L Magnusson
- Division of Renal and Vascular Physiology, Department of Biomedical Sciences, The Panum Institute, University of Copenhagen, Denmark
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Hassanin HA, El-Shahat MF, DeBeer S, Smith CA, Brasch NE. Redetermination of the X-ray structure of nitroxylcobalamin: base-on nitroxylcobalamin exhibits a remarkably long Co-N(dimethylbenzimidazole) bond distance. Dalton Trans 2010; 39:10626-30. [PMID: 20890534 DOI: 10.1039/c0dt00628a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The X-ray structures of three new crystals of nitroxylcobalamin (NOCbl) have been determined. Unlike our earlier reported structure in which NOCbl was partially oxidized (L. Hannibal, C. A. Smith, D. W. Jacobsen and N. E. Brasch, Angew. Chem., Int. Ed. 2007, 46, 5140), the O atom of the nitroxyl ligand is located in a single position with a N=O bond distance of 1.12-1.14 Å, consistent with a double bond. The Co-N-O angle is in the 118.9-120.3 Å range. The α-axial Co-N(dimethylbenzimidazole) (Co-NB3) bond distance is a remarkable 2.32-2.35 Å in length, ~0.1 Å longer than that reported for all other cobalamin structures. The change in the Gibbs free energy for the base-on/base-off equilibrium now correlates extremely well with the Co-NB3 bond distance, as observed for other cobalamins.
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Affiliation(s)
- Hanaa A Hassanin
- Department of Chemistry, Kent State University, Kent, OH 44242, USA
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29
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Félétou M. Calcium-activated potassium channels and endothelial dysfunction: therapeutic options? Br J Pharmacol 2009; 156:545-62. [PMID: 19187341 DOI: 10.1111/j.1476-5381.2009.00052.x] [Citation(s) in RCA: 191] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
The three subtypes of calcium-activated potassium channels (K(Ca)) of large, intermediate and small conductance (BK(Ca), IK(Ca) and SK(Ca)) are present in the vascular wall. In healthy arteries, BK(Ca) channels are preferentially expressed in vascular smooth muscle cells, while IK(Ca) and SK(Ca) are preferentially located in endothelial cells. The activation of endothelial IK(Ca) and SK(Ca) contributes to nitric oxide (NO) generation and is required to elicit endothelium-dependent hyperpolarizations. In the latter responses, the hyperpolarization of the smooth muscle cells is evoked either via electrical coupling through myo-endothelial gap junctions or by potassium ions, which by accumulating in the intercellular space activate the inwardly rectifying potassium channel Kir2.1 and/or the Na(+)/K(+)-ATPase. Additionally, endothelium-derived factors such as cytochrome P450-derived epoxyeicosatrienoic acids and under some circumstances NO, prostacyclin, lipoxygenase products and hydrogen peroxide (H(2)O(2)) hyperpolarize and relax the underlying smooth muscle cells by activating BK(Ca). In contrast, cytochrome P450-derived 20-hydroxyeicosatetraenoic acid and various endothelium-derived contracting factors inhibit BK(Ca). Aging and cardiovascular diseases are associated with endothelial dysfunctions that can involve a decrease in NO bioavailability, alterations of EDHF-mediated responses and/or enhanced production of endothelium-derived contracting factors. Because potassium channels are involved in these endothelium-dependent responses, activation of endothelial and/or smooth muscle K(Ca) could prevent the occurrence of endothelial dysfunction. Therefore, direct activators of these potassium channels or compounds that regulate their activity or their expression may be of some therapeutic interest. Conversely, blockers of IK(Ca) may prevent restenosis and that of BK(Ca) channels sepsis-dependent hypotension.
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Affiliation(s)
- Michel Félétou
- Department of Angiology, Institut de Recherches Servier, Suresnes, France.
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Hassanin HA, Hannibal L, Jacobsen DW, Brown KL, Marques HM, Brasch NE. NMR spectroscopy and molecular modelling studies of nitrosylcobalamin: further evidence that the deprotonated, base-off form is important for nitrosylcobalamin in solution. Dalton Trans 2009:424-33. [PMID: 19122899 PMCID: PMC2754767 DOI: 10.1039/b810895a] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The structure of nitrosylcobalamin (NOCbl) in solution has been studied by NMR spectroscopy and the 1H and 13C NMR spectra have been assigned. 13C and 31P NMR chemical shifts, the UV-vis spectrum of NOCbl and the observed pKbase-off value of approximately 5.1 for NOCbl provide evidence that a significant fraction of NOCbl is present in the base-off, 5,6-dimethylbenzimidazole (DMB) deprotonated, form in solution. NOE-restrained molecular mechanics modelling of base-on NOCbl gave annealed structures with minor conformational differences in the flexible side chains and the nucleotide loop position compared with the X-ray structure. A molecular dynamics simulation at 300 K showed that DMB remains in close proximity to the alpha face of the corrin in the base-off form of NOCbl. Simulated annealing calculations produced two major conformations of base-off NOCbl. In the first, the DMB is perpendicular to the corrin and its B3 nitrogen is about 3.1 A away from and pointing directly at the metal ion; in the second the DMB is parallel to and tucked beneath the D ring of the corrin.
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Affiliation(s)
- Hanaa A. Hassanin
- Department of Chemistry, School of Biomedical Sciences, Kent State University, Kent, OH44242
| | - Luciana Hannibal
- Department of Chemistry, School of Biomedical Sciences, Kent State University, Kent, OH44242
- School of Biomedical Sciences, Kent State University, Kent, OH 44242. E-mail:
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Donald W. Jacobsen
- School of Biomedical Sciences, Kent State University, Kent, OH 44242. E-mail:
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH 44106
| | - Kenneth L. Brown
- Department of Chemistry and Biochemistry, Ohio University, Athens, OH 45701
| | - Helder M. Marques
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, PO Wits, Johannesburg, 2050, South Africa. E-mail:
| | - Nicola E. Brasch
- Department of Chemistry, School of Biomedical Sciences, Kent State University, Kent, OH44242
- School of Biomedical Sciences, Kent State University, Kent, OH 44242. E-mail:
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Park WS, Han J, Earm YE. Physiological role of inward rectifier K+ channels in vascular smooth muscle cells. Pflugers Arch 2008; 457:137-47. [DOI: 10.1007/s00424-008-0512-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2007] [Revised: 03/19/2008] [Accepted: 03/25/2008] [Indexed: 10/22/2022]
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Hannibal L, Smith CA, Jacobsen DW, Brasch NE. Nitroxylcob(III)alamin: synthesis and X-ray structural characterization. Angew Chem Int Ed Engl 2007; 46:5140-3. [PMID: 17542034 PMCID: PMC2764306 DOI: 10.1002/anie.200701131] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Luciana Hannibal
- Department of Chemistry and School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA
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Hannibal L, Smith C, Jacobsen D, Brasch N. Nitroxylcob(III)alamin: Synthesis and X-ray Structural Characterization. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200701131] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Abstract
Endothelium-dependent relaxations are attributed to the release of various factors, such as nitric oxide, carbon monoxide, reactive oxygen species, adenosine, peptides and arachidonic acid metabolites derived from the cyclooxygenases, lipoxygenases, and cytochrome P450 monooxygenases pathways. The hyperpolarization of the smooth muscle cell can contribute to or be an integral part of the mechanisms underlying the relaxations elicited by virtually all these endothelial mediators. These endothelium-derived factors can activate different families of K(+) channels of the vascular smooth muscle. Other events associated with the hyperpolarization of both the endothelial and the vascular smooth muscle cells (endothelium-derived hyperpolarizing factor (EDHF)-mediated responses) contribute also to endothelium-dependent relaxations. These responses involve an increase in the intracellular Ca(2+) concentration of the endothelial cells followed by the opening of Ca(2+)-activated K(+) channels of small and intermediate conductance and the subsequent hyperpolarization of these cells. Then, the endothelium-dependent hyperpolarization of the underlying smooth muscle cells can be evoked by direct electrical coupling through myoendothelial junctions and/or the accumulation of K(+) ions in the intercellular space between the two cell types. These various mechanisms are not necessarily mutually exclusive and, depending on the vascular bed and the experimental conditions, can occur simultaneously or sequentially, or also may act synergistically.
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Affiliation(s)
- Michel Félétou
- Department of Angiology, Institut de Recherches Servier, Suresnes, France
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35
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Rust MB, Faulhaber J, Budack MK, Pfeffer C, Maritzen T, Didié M, Beck FX, Boettger T, Schubert R, Ehmke H, Jentsch TJ, Hübner CA. Neurogenic Mechanisms Contribute to Hypertension in Mice With Disruption of the K-Cl Cotransporter KCC3. Circ Res 2006; 98:549-56. [PMID: 16424367 DOI: 10.1161/01.res.0000204449.83861.22] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The neurodegenerative disorder Andermann syndrome is caused by mutations of the K-Cl cotransporter KCC3. Mice with a targeted disruption of the corresponding gene, Slc12a6, reproduce neurodegeneration of the peripheral and central nervous system (CNS) and display arterial hypertension. Kcc3 is expressed in numerous tissues, including the CNS and vascular smooth muscle cells. As the intracellular chloride concentration may influence myogenic tone and hence blood pressure, we measured the chloride concentration in vascular smooth muscle cells. It was indeed increased in superficial brain arteries and saphenous arteries of Kcc3(-/-) mice. Isolated saphenous arteries and their third-order branches, however, reacted indistinguishably to changes in intravascular pressure, stimulation of alpha1-adrenoreceptors, exogenous nitric oxide, or blockade of calcium-activated chloride channels. Likewise, the responses to alpha1-adrenergic stimulation or exogenous nitric oxide in vivo were identical in both genotypes. These results argue against a major vascular-intrinsic component of arterial hypertension in Kcc3(-/-) mice. In contrast, either alpha1-adrenergic blockade or inhibition of ganglionic transmission abolished the difference in arterial blood pressure between both genotypes. This demonstrates a neurogenic component in the maintenance of this phenotype, which is further supported by an increase of urinary norepinephrine and epinephrine excretion in Kcc3(-/-) mice. Our data indicate that local control of myogenic tone does not require KCC3 and that hypertension in Kcc3(-/-) mice depends on an elevated sympathetic tone.
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Affiliation(s)
- Marco B Rust
- Zentrum für Molekulare Neurobiologie Hamburg, Universität Hamburg, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
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Abstract
Vascular smooth muscle (VSM) cells, endothelial cells (EC), and pericytes that form the walls of vessels in the microcirculation express a diverse array of ion channels that play an important role in the function of these cells and the microcirculation in both health and disease. This brief review focuses on the K+ channels expressed in smooth muscle and endothelial cells in arterioles. Microvascular VSM cells express at least four different classes of K+ channels, including inward-rectifier K+ channels (Kin), ATP-sensitive K+ channels (KATP), voltage-gated K+ channels (Kv), and large conductance Ca2+-activated K+ channels (BKCa). VSM KIR participate in dilation induced by elevated extracellular K+ and may also be activated by C-type natriuretic peptide, a putative endothelium-derived hyperpolarizing factor (EDHF). Vasodilators acting through cAMP or cGMP signaling pathways in VSM may open KATP, Kv, and BKCa, causing membrane hyperpolarization and vasodilation. VSMBKc. may also be activated by epoxides of arachidonic acid (EETs) identified as EDHF in some systems. Conversely, vasoconstrictors may close KATP, Kv, and BKCa through protein kinase C, Rho-kinase, or c-Src pathways and contribute to VSM depolarization and vasoconstriction. At the same time Kv and BKCa act in a negative feedback manner to limit depolarization and prevent vasospasm. Microvascular EC express at least 5 classes of K+ channels, including small (sKCa) and intermediate(IKCa) conductance Ca2+-activated K+ channels, Kin, KATP, and Kv. Both sK and IK are opened by endothelium-dependent vasodilators that increase EC intracellular Ca2+ to cause membrane hyper-polarization that may be conducted through myoendothelial gap junctions to hyperpolarize and relax arteriolar VSM. KIR may serve to amplify sKCa- and IKCa-induced hyperpolarization and allow active transmission of hyperpolarization along EC through gap junctions. EC KIR channels may also be opened by elevated extracellular K+ and participate in K+-induced vasodilation. EC KATP channels may be activated by vasodilators as in VSM. Kv channels may provide a negative feedback mechanism to limit depolarization in some endothelial cells.
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Affiliation(s)
- William F Jackson
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI 49008-5410, USA.
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