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Hariki A, Dal Din A, Amin OJ, Yamaguchi T, Badura A, Kriegner D, Edmonds KW, Campion RP, Wadley P, Backes D, Veiga LSI, Dhesi SS, Springholz G, Šmejkal L, Výborný K, Jungwirth T, Kuneš J. X-Ray Magnetic Circular Dichroism in Altermagnetic α-MnTe. Phys Rev Lett 2024; 132:176701. [PMID: 38728732 DOI: 10.1103/physrevlett.132.176701] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 02/01/2024] [Accepted: 03/20/2024] [Indexed: 05/12/2024]
Abstract
Altermagnetism is a recently identified magnetic symmetry class combining characteristics of conventional collinear ferromagnets and antiferromagnets, that were regarded as mutually exclusive, and enabling phenomena and functionalities unparalleled in either of the two traditional elementary magnetic classes. In this work we use symmetry, ab initio theory, and experiments to explore x-ray magnetic circular dichroism (XMCD) in the altermagnetic class. As a representative material for our XMCD study we choose α-MnTe with compensated antiparallel magnetic order in which an anomalous Hall effect has been already demonstrated. We predict and experimentally confirm a characteristic XMCD line shape for compensated moments lying in a plane perpendicular to the light propagation vector. Our results highlight the distinct phenomenology in altermagnets of this time-reversal symmetry breaking response, and its potential utility for element-specific spectroscopy and microscopy.
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Affiliation(s)
- A Hariki
- Department of Physics and Electronics, Graduate School of Engineering, Osaka Metropolitan University, 1-1 Gakuen-cho, Nakaku, Sakai, Osaka 599-8531, Japan
| | - A Dal Din
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - O J Amin
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - T Yamaguchi
- Department of Physics and Electronics, Graduate School of Engineering, Osaka Metropolitan University, 1-1 Gakuen-cho, Nakaku, Sakai, Osaka 599-8531, Japan
| | - A Badura
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, 162 00 Praha 6 Czech Republic
| | - D Kriegner
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, 162 00 Praha 6 Czech Republic
| | - K W Edmonds
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - R P Campion
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - P Wadley
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - D Backes
- Diamond Light Source, Chilton OX11 0DE, United Kingdom
| | - L S I Veiga
- Diamond Light Source, Chilton OX11 0DE, United Kingdom
| | - S S Dhesi
- Diamond Light Source, Chilton OX11 0DE, United Kingdom
| | - G Springholz
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenbergerstraße 69, 4040 Linz, Austria
| | - L Šmejkal
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, 162 00 Praha 6 Czech Republic
- Institut für Physik, Johannes Gutenberg Universität Mainz, D-55099 Mainz, Germany
| | - K Výborný
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, 162 00 Praha 6 Czech Republic
| | - T Jungwirth
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, 162 00 Praha 6 Czech Republic
| | - J Kuneš
- Institute for Solid State Physics, TU Wien, 1040 Vienna, Austria
- Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czechia
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2
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Holá L, Tureckiuová T, Kuneš J, Železná B, Maletínská L. High-Fat Diet Induces Resistance to Ghrelin and LEAP2 Peptide Analogs in Mice. Physiol Res 2023; 72:607-619. [PMID: 38015760 PMCID: PMC10751049 DOI: 10.33549/physiolres.935189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 08/01/2023] [Indexed: 01/05/2024] Open
Abstract
Recent data suggest that the orexigenic peptide ghrelin and liver-expressed antimicrobial peptide 2 (LEAP2) have opposing effects on food intake regulation. Although circulating ghrelin is decreased in obesity, peripheral ghrelin administration does not induce food intake in obese mice. Limited information is available on ghrelin resistance in relation to LEAP2. In this study, the interplay between ghrelin and LEAP2 in obesity induced by a high-fat (HF) diet in mice was studied. First, the progression of obesity and intolerance to glucose together with plasma levels of active and total ghrelin, leptin, as well as liver LEAP2 mRNA expression at different time points of HF diet feeding was examined. In addition, the impact of switch from a HF diet to a standard diet on plasma ghrelin and LEAP2 production was studied. Second, sensitivity to the stable ghrelin analogue [Dpr3]Ghrelin or our novel LEAP2 analogue palm-LEAP2(1-14) during the progression of HF diet-induced obesity and after the switch for standard diet was investigated. Food intake was monitored after acute subcutaneous administration. HF diet feeding decreased both active and total plasma ghrelin and increased liver LEAP2 mRNA expression along with intolerance to glucose and the switch to a standard diet normalized liver LEAP2 mRNA expression and plasma level of active ghrelin, but not of total ghrelin. Additionally, our study demonstrates that a HF diet causes resistance to [Dpr3]Ghrelin, reversible by switch to St diet, followed by resistance to palm-LEAP2(1-14). Further studies are needed to determine the long-term effects of LEAP2 analogues on obesity-related ghrelin resistance.
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Affiliation(s)
- L Holá
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Praha 6, Czech Republic.
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Kuneš J, Hojná S, Mráziková L, Montezano A, Touyz RM, Maletínská L. Obesity, Cardiovascular and Neurodegenerative Diseases: Potential Common Mechanisms. Physiol Res 2023; 72:S73-S90. [PMID: 37565414 PMCID: PMC10660578 DOI: 10.33549/physiolres.935109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 05/12/2023] [Indexed: 12/01/2023] Open
Abstract
The worldwide increase in the incidence of obesity and cardiovascular and neurodegenerative diseases, e.g. Alzheimer's disease, is related to many factors, including an unhealthy lifestyle and aging populations. However, the interconnection between these diseases is not entirely clear, and it is unknown whether common mechanisms underlie these conditions. Moreover, there are currently no fully effective therapies for obesity and neurodegeneration. While there has been extensive research in preclinical models addressing these issues, the experimental findings have not been translated to the clinic. Another challenge relates to the time of onset of individual diseases, which may not be easily identified, since there are no specific indicators or biomarkers that define disease onset. Hence knowing when to commence preventive treatment is unclear. This is especially pertinent in neurodegenerative diseases, where the onset of the disease may be subtle and occur decades before the signs and symptoms manifest. In metabolic and cardiovascular disorders, the risk may occur in-utero, in line with the concept of fetal programming. This review provides a brief overview of the link between obesity, cardiovascular and neurodegenerative diseases and discusses potential common mechanisms including the role of the gut microbiome.
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Affiliation(s)
- J Kuneš
- Institute of Physiology AS CR, Prague, Czech Republic. . Research Institute of McGill University Health Centre (RI-MUHC), Québac, Canada,
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Pirník Z, Kořínková L, Osacká J, Železná B, Kuneš J, Maletínská L. Cholecystokinin system is involved in the anorexigenic effect of peripherally applied palmitoylated prolactin-releasing peptide in fasted mice. Physiol Res 2021; 70:579-590. [PMID: 34062082 PMCID: PMC8820541 DOI: 10.33549/physiolres.934694] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 04/22/2021] [Indexed: 11/25/2022] Open
Abstract
Prolactin-releasing peptide (PrRP) has been proposed to mediate the central satiating effects of cholecystokinin (CCK) through the vagal CCK1 receptor. PrRP acts as an endogenous ligand of G protein-coupled receptor 10 (GPR10), which is expressed at the highest levels in brain areas related to food intake regulation, e.g., the paraventricular hypothalamic nucleus (PVN) and nucleus of the solitary tract (NTS). The NTS and PVN are also significantly activated after peripheral CCK administration. The aim of this study was to determine whether the endogenous PrRP neuronal system in the brain is involved in the central anorexigenic effect of the peripherally administered CCK agonist JMV236 or the CCK1 antagonist devazepide and whether the CCK system is involved in the central anorexigenic effect of the peripherally applied lipidized PrRP analog palm-PrRP31 in fasted lean mice. The effect of devazepide and JMV236 on the anorexigenic effects of palm-PrRP31 as well as devazepide combined with JMV236 and palm-PrRP31 on food intake and Fos cell activation in the PVN and caudal NTS was examined. Our results suggest that the anorexigenic effect of JMV236 is accompanied by activation of PrRP neurons of the NTS in a CCK1 receptor-dependent manner. Moreover, while the anorexigenic effect of palm-PrRP31 was not affected by JMV236, it was partially attenuated by devazepide in fasted mice. The present findings indicate that the exogenously influenced CCK system may be involved in the central anorexigenic effect of peripherally applied palm-PrRP31, which possibly indicates some interaction between the CCK and PrRP neuronal systems.
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Affiliation(s)
- Z Pirník
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czech Republic,
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5
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Ebad-Allah J, Rojewski S, Vöst M, Eickerling G, Scherer W, Uykur E, Sankar R, Varrassi L, Franchini C, Ahn KH, Kuneš J, Kuntscher CA. Pressure-Induced Excitations in the Out-of-Plane Optical Response of the Nodal-Line Semimetal ZrSiS. Phys Rev Lett 2021; 127:076402. [PMID: 34459638 DOI: 10.1103/physrevlett.127.076402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 06/17/2021] [Indexed: 06/13/2023]
Abstract
The anisotropic optical response of the layered, nodal-line semimetal ZrSiS at ambient and high pressure is investigated by frequency-dependent reflectivity measurements for the polarization along and perpendicular to the layers. The highly anisotropic optical conductivity is in very good agreement with results from density-functional theory calculations and confirms the anisotropic character of ZrSiS. Whereas the in-plane optical conductivity shows only modest pressure-induced changes, we found strong effects on the out-of-plane optical conductivity spectrum of ZrSiS, with the appearance of two prominent excitations. These pronounced pressure-induced effects can neither be attributed to a structural phase transition according to our single-crystal x-ray diffraction measurements, nor can they be explained by electronic correlation and electron-hole pairing effects, as revealed by theoretical calculations. Our findings are discussed in the context of the recently proposed excitonic insulator phase in ZrSiS.
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Affiliation(s)
- J Ebad-Allah
- Experimentalphysik II, University of Augsburg, 86159 Augsburg, Germany
- Department of Physics, Tanta University, 31527 Tanta, Egypt
| | - S Rojewski
- Experimentalphysik II, University of Augsburg, 86159 Augsburg, Germany
| | - M Vöst
- Chair of Chemical Physics and Materials Science, Institute of Physics, University of Augsburg, 86159 Augsburg, Germany
| | - G Eickerling
- Chair of Chemical Physics and Materials Science, Institute of Physics, University of Augsburg, 86159 Augsburg, Germany
| | - W Scherer
- Chair of Chemical Physics and Materials Science, Institute of Physics, University of Augsburg, 86159 Augsburg, Germany
| | - E Uykur
- 1. Physikalisches Institut, Universität Stuttgart, 70569 Stuttgart, Germany
| | - Raman Sankar
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - L Varrassi
- Department of Physics and Astronomy, Alma Mater Studiorum-Università di Bologna, Bologna 40127, Italy
| | - C Franchini
- Department of Physics and Astronomy, Alma Mater Studiorum-Università di Bologna, Bologna 40127, Italy
- University of Vienna, Faculty of Physics and Center for Computational Materials Science, 1090 Vienna, Austria
| | - K-H Ahn
- Institute of Solid State Physics, TU Wien, 1020 Vienna, Austria
- Institute of Physics, The Czech Academy of Sciences, 16200 Praha, Czechia
| | - J Kuneš
- Institute of Solid State Physics, TU Wien, 1020 Vienna, Austria
- Institute of Physics, The Czech Academy of Sciences, 18221 Praha, Czechia
| | - C A Kuntscher
- Experimentalphysik II, University of Augsburg, 86159 Augsburg, Germany
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Kořínková L, Pražienková V, Černá L, Karnošová A, Železná B, Kuneš J, Maletínská L. Pathophysiology of NAFLD and NASH in Experimental Models: The Role of Food Intake Regulating Peptides. Front Endocrinol (Lausanne) 2020; 11:597583. [PMID: 33324348 PMCID: PMC7726422 DOI: 10.3389/fendo.2020.597583] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 10/28/2020] [Indexed: 12/12/2022] Open
Abstract
Obesity, diabetes, insulin resistance, sedentary lifestyle, and Western diet are the key factors underlying non-alcoholic fatty liver disease (NAFLD), one of the most common liver diseases in developed countries. In many cases, NAFLD further progresses to non-alcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and to hepatocellular carcinoma. The hepatic lipotoxicity and non-liver factors, such as adipose tissue inflammation and gastrointestinal imbalances were linked to evolution of NAFLD. Nowadays, the degree of adipose tissue inflammation was shown to directly correlate with the severity of NAFLD. Consumption of higher caloric intake is increasingly emerging as a fuel of metabolic inflammation not only in obesity-related disorders but also NAFLD. However, multiple causes of NAFLD are the reason why the mechanisms of NAFLD progression to NASH are still not well understood. In this review, we explore the role of food intake regulating peptides in NAFLD and NASH mouse models. Leptin, an anorexigenic peptide, is involved in hepatic metabolism, and has an effect on NAFLD experimental models. Glucagon-like peptide-1 (GLP-1), another anorexigenic peptide, and GLP-1 receptor agonists (GLP-1R), represent potential therapeutic agents to prevent NAFLD progression to NASH. On the other hand, the deletion of ghrelin, an orexigenic peptide, prevents age-associated hepatic steatosis in mice. Because of the increasing incidence of NAFLD and NASH worldwide, the selection of appropriate animal models is important to clarify aspects of pathogenesis and progression in this field.
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Affiliation(s)
- L. Kořínková
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czechia
| | - V. Pražienková
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czechia
| | - L. Černá
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czechia
| | - A. Karnošová
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czechia
| | - B. Železná
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czechia
| | - J. Kuneš
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czechia
- Institute of Physiology, Czech Academy of Sciences, Prague, Czechia
| | - Lenka Maletínská
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czechia
- *Correspondence: Lenka Maletínská,
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7
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Geffroy D, Kaufmann J, Hariki A, Gunacker P, Hausoel A, Kuneš J. Collective Modes in Excitonic Magnets: Dynamical Mean-Field Study. Phys Rev Lett 2019; 122:127601. [PMID: 30978073 DOI: 10.1103/physrevlett.122.127601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 01/23/2019] [Indexed: 06/09/2023]
Abstract
We present a dynamical mean-field study of dynamical susceptibilities in the two-band Hubbard model. Varying the model parameters we analyze the two-particle excitations in the normal as well as in the ordered phase, an excitonic condensate. The two-particle dynamical mean-field theory spectra in the ordered phase reveal the gapless Goldstone modes arising from spontaneous breaking of continuous symmetries. We also observe the gapped Higgs mode, characterized by vanishing of the gap at the phase boundary. Qualitative changes observed in the spin susceptibility can be used as an experimental probe to identify the excitonic condensation.
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Affiliation(s)
- D Geffroy
- Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czechia
- Institute for Solid State Physics, TU Wien, 1040 Vienna, Austria
| | - J Kaufmann
- Institute for Solid State Physics, TU Wien, 1040 Vienna, Austria
| | - A Hariki
- Institute for Solid State Physics, TU Wien, 1040 Vienna, Austria
| | - P Gunacker
- Institute for Solid State Physics, TU Wien, 1040 Vienna, Austria
| | - A Hausoel
- Institute for Theoretical Physics and Astrophysics, University of Würzburg, Am Hubland 97074 Würzburg, Germany
| | - J Kuneš
- Institute for Solid State Physics, TU Wien, 1040 Vienna, Austria
- Institute of Physics, Czech Academy of Sciences, Na Slovance 2, 182 21 Praha 8, Czechia
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8
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Fernández Afonso J, Sotnikov A, Kuneš J. Theoretical investigation of excitonic magnetism in LaSrCoO 4. J Phys Condens Matter 2018; 30:135603. [PMID: 29460844 DOI: 10.1088/1361-648x/aab0bb] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We use the LDA+U approach to search for possible ordered ground states of LaSrCoO4. We find a staggered arrangement of magnetic multipoles to be stable over a broad range of Co 3d interaction parameters. This ordered state can be described as a spin-density-wave-type condensate of [Formula: see text] excitons carrying spin S = 1. Further, we construct an effective strong-coupling model, calculate the exciton dispersion and investigate closing of the exciton gap, which marks the exciton condensation instability. Comparing the layered LaSrCoO4 with its pseudo cubic analog LaCoO3, we find that for the same interaction parameters the excitonic gap is smaller (possibly vanishing) in the layered cobaltite.
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Affiliation(s)
- J Fernández Afonso
- Institute of Solid State Physics, TU Wien, Wiedner Hauptstr. 8, 1020 Vienna, Austria
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9
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Popelová A, Kákonová A, Hrubá L, Kuneš J, Maletínská L, Železná B. Potential neuroprotective and anti-apoptotic properties of a long-lasting stable analog of ghrelin: an in vitro study using SH-SY5Y cells. Physiol Res 2018; 67:339-346. [PMID: 29303606 DOI: 10.33549/physiolres.933761] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Neurodegenerative disorders, such as Alzheimer's disease (AD) and Parkinson's disease (PD), are increasing in prevalence. Currently, there are no effective and specific treatments for these disorders. Recently, positive effects of the orexigenic hormone ghrelin on memory and learning were demonstrated in mouse models of AD and PD. In this study, we tested the potential neuroprotective properties of a stable and long-lasting ghrelin analog, Dpr(3)ghrelin (Dpr(3)ghr), in SH-SY5Y neuroblastoma cells stressed with 1.2 mM methylglyoxal (MG), a toxic endogenous by-product of glycolysis, and we examined the impact of Dpr(3)ghr on apoptosis. Pre-treatment with both 10(-5) and 10(-7) M Dpr(3)ghr resulted in increased viability in SH-SY5Y cells (determined by MTT staining), as well as reduced cytotoxicity of MG in these cells (determined by LDH assay). Dpr(3)ghr increased viability by altering pro-apoptotic and viability markers: Bax was decreased, Bcl-2 was increased, and the Bax/Bcl-2 ratio was attenuated. The ghrelin receptor GHS-R1 and Dpr(3)ghr-induced activation of PBK/Akt were immuno-detected in SH-SY5Y cells to demonstrate the presence of GHS-R1 and GHS-R1 activation, respectively. We demonstrated that Dpr(3)ghr protected SH-SY5Y cells against MG-induced neurotoxicity and apoptosis. Our data suggest that stable ghrelin analogs may be candidates for the effective treatment of neurodegenerative disorders.
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Affiliation(s)
- A Popelová
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czech Republic.
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10
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Horký P, Voráčová M, Konečná K, Sedlák D, Bartůněk P, Vacek J, Kuneš J, Pour M. Nontoxic combretafuranone analogues with high in vitro antibacterial activity. Eur J Med Chem 2018; 143:843-853. [PMID: 29223099 DOI: 10.1016/j.ejmech.2017.11.078] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 11/27/2017] [Accepted: 11/27/2017] [Indexed: 12/12/2022]
Abstract
A library of thirty two 3,4-diphenylfuranones related to both combretastatin A-4 and antifungal 5-(acyloxymethyl)-3-(halophenyl)-2,5-dihydrofuran-2-ones was prepared. Cytotoxic effects on a panel of cancer and normal cell lines and antiinfective activity were evaluated, and the data were complemented with tests for the activation of caspase 3 and 7. High cytotoxicity was observed in some of the halogenated analogues, eg. 3-(3,4-dichlorophenyl)-4-(4-methylphenyl)-2,5-dihydrofuran-2-one with IC50 0.12-0.23 μM, but the compounds were also highly toxic against non-malignant control cells. More importantly, notable antibacterial activity indicating G+ selectivity has been found in the 3,4-diarylfuranone class of compounds for the first time. Hydroxymethylation of furanone C5 knocked out cytotoxic effects (up to 40 μM) while maintaining significant activity against Staphylococcus strains in some derivatives. MIC95 of the most promising compound, 3-(4-bromophenyl)-5,5-bis(hydroxymethyl)-4-(4-methylphenyl)-2,5-dihydrofuran-2-one against S. aureus strain ATCC 6538 was 0.98 μM (0.38 μg/mL) and 3.9 μM (1.52 μg/mL) after 24 and 48 h, respectively.
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Affiliation(s)
- P Horký
- Department of Bioorganic and Organic Chemistry, Faculty of Pharmacy, Charles University, Heyrovského 1203, 500 05 Hradec Králové, Czech Republic
| | - M Voráčová
- Department of Bioorganic and Organic Chemistry, Faculty of Pharmacy, Charles University, Heyrovského 1203, 500 05 Hradec Králové, Czech Republic
| | - K Konečná
- Department of Biological and Medical Sciences, Faculty of Pharmacy, Charles University, Heyrovského 1203, 500 05 Hradec Králové, Czech Republic
| | - D Sedlák
- CZ-OPENSCREEN: National Infrastructure for Chemical Biology, Institute of Molecular Genetics, Czech Academy of Sciences, Vídeňská 1083, 142 20 Praha 4, Czech Republic
| | - P Bartůněk
- CZ-OPENSCREEN: National Infrastructure for Chemical Biology, Institute of Molecular Genetics, Czech Academy of Sciences, Vídeňská 1083, 142 20 Praha 4, Czech Republic
| | - J Vacek
- Department of Medical Chemistry and Biochemistry, Palacký University, Hněvotínská 3, 775 15 Olomouc, Czech Republic
| | - J Kuneš
- Department of Bioorganic and Organic Chemistry, Faculty of Pharmacy, Charles University, Heyrovského 1203, 500 05 Hradec Králové, Czech Republic
| | - M Pour
- Department of Bioorganic and Organic Chemistry, Faculty of Pharmacy, Charles University, Heyrovského 1203, 500 05 Hradec Králové, Czech Republic.
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Wadley P, Edmonds KW, Shahedkhah MR, Campion RP, Gallagher BL, Železný J, Kuneš J, Novák V, Jungwirth T, Saidl V, Němec P, Maccherozzi F, Dhesi SS. Control of antiferromagnetic spin axis orientation in bilayer Fe/CuMnAs films. Sci Rep 2017; 7:11147. [PMID: 28894219 PMCID: PMC5593844 DOI: 10.1038/s41598-017-11653-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 08/25/2017] [Indexed: 11/22/2022] Open
Abstract
Using x-ray magnetic circular and linear dichroism techniques, we demonstrate a collinear exchange coupling between an epitaxial antiferromagnet, tetragonal CuMnAs, and an Fe surface layer. A small uncompensated Mn magnetic moment is observed which is antiparallel to the Fe magnetization. The staggered magnetization of the 5 nm thick CuMnAs layer is rotatable under small magnetic fields, due to the interlayer exchange coupling. This allows us to obtain the x-ray magnetic linear dichroism spectra for different crystalline orientations of CuMnAs in the (001) plane. This is a key parameter for enabling the understanding of domain structures in CuMnAs imaged using x-ray magnetic linear dichroism microscopy techniques.
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Affiliation(s)
- P Wadley
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, United Kingdom.
| | - K W Edmonds
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - M R Shahedkhah
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - R P Campion
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - B L Gallagher
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - J Železný
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, 162 00, Praha 6, Czech Republic.,Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - J Kuneš
- Institute of Physics, Czech Academy of Sciences, Na Slovance 1999/2, 182 21, Praha 8, Czech Republic.,Institute of Solid State Physics, TU Wien, Wiedner Hauptstr. 8, 1040, Wien, Austria
| | - V Novák
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, 162 00, Praha 6, Czech Republic
| | - T Jungwirth
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, United Kingdom.,Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, 162 00, Praha 6, Czech Republic
| | - V Saidl
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, 162 00, Praha 6, Czech Republic.,Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16, Praha 2, Czech Republic
| | - P Němec
- Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16, Praha 2, Czech Republic
| | - F Maccherozzi
- Diamond Light Source, Chilton, Didcot, Oxfordshire, OX11 0DE, United Kingdom
| | - S S Dhesi
- Diamond Light Source, Chilton, Didcot, Oxfordshire, OX11 0DE, United Kingdom
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Vokurková M, Rauchová H, Dobešová Z, Loukotová J, Nováková O, Kuneš J, Zicha J. The influence of erythrocyte maturity on ion transport and membrane lipid composition in the rat. Physiol Res 2016; 65:91-9. [PMID: 26988297 DOI: 10.33549/physiolres.933326] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Significant relationships between ion transport and membrane lipid composition (cholesterol, total phospholipids and sphingomyelins) were found in erythrocytes of salt hypertensive Dahl rats. In these animals mean cellular hemoglobin content correlated negatively with Na(+)-K(+) pump activity and Na(+) leak but positively with Na(+)-K(+) cotransport activity. Immature erythrocytes exhibit lower mean cellular hemoglobin content (MCHC) than mature ones. The aim of the present study was to find a relationship between erythrocyte maturity, membrane lipid composition and ion transport activity in Wistar rats aged three months which were subjected to repeated hemorrhage (blood loss 2 ml/day for 6 days) to enrich circulating erythrocytes with immature forms. Immature and mature erythrocyte fractions in control and hemorrhaged rats were separated by repeated centrifugation. Hemorrhaged rats had increased number of reticulocytes but reduced hematocrit and MCHC compared to control rats. Immature erythrocytes of hemorrhaged rats differed from mature ones of control animals by elevated Na(+)-K(+) pump activity, reduced Na(+)-K(+) cotransport activity and increased Rb(+) leak. These ion transport changes in immature erythrocytes were accompanied by higher concentration of total phospholipids in their cell membranes. Membrane phospholipid content correlated positively with Na(+)-K(+) pump activity and cation leaks but negatively with Na(+)-K(+) cotransport activity. Moreover, they were also negatively related with MCHC which correlated negatively with Na(+)-K(+) pump activity and Rb(+) leak but positively with Na(+)-K(+) cotransport activity. Thus certain abnormalities of erythrocyte ion transport and membrane lipid composition detected in hypertensive animals might be caused by higher incidence of immature cells.
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Affiliation(s)
- M Vokurková
- Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic.
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13
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Mikulášková B, Maletínská L, Zicha J, Kuneš J. The role of food intake regulating peptides in cardiovascular regulation. Mol Cell Endocrinol 2016; 436:78-92. [PMID: 27450151 DOI: 10.1016/j.mce.2016.07.021] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 07/07/2016] [Accepted: 07/19/2016] [Indexed: 12/11/2022]
Abstract
Obesity is a risk factor that worsens cardiovascular events leading to higher morbidity and mortality. However, the exact mechanisms of relation between obesity and cardiovascular events are unclear. Nevertheless, it has been demonstrated that pharmacological therapy for obesity has great potential to improve some cardiovascular problems. Therefore, it is important to determine the common mechanisms regulating both food intake and blood pressure. Several hormones produced by peripheral tissues work together with neuropeptides involved in the regulation of both food intake and blood pressure. Anorexigenic (food intake lowering) hormones such as leptin, glucagon-like peptide-1 and cholecystokinin cooperate with α-melanocyte-stimulating hormone, cocaine- and amphetamine-regulated peptide as well as prolactin-releasing peptide. Curiously their collective actions result in increased sympathetic activity, especially in the kidney, which could be one of the factors responsible for the blood pressure increases seen in obesity. On the other hand, orexigenic (food intake enhancing) peptides, especially ghrelin released from the stomach and acting in the brain, cooperates with orexins, neuropeptide Y, melanin-concentrating hormone and galanin, which leads to decreased sympathetic activity and blood pressure. This paradox should be intensively studied in the future. Moreover, it is important to know that the hypothalamus together with the brainstem seem to be major structures in the regulation of food intake and blood pressure. Thus, the above mentioned regions might be essential brain components in the transmission of peripheral signals to the central effects. In this short review, we summarize the current information on cardiovascular effects of food intake regulating peptides.
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Affiliation(s)
- B Mikulášková
- Institute of Physiology AS CR, Prague, Czech Republic; Institute of Organic Chemistry and Biochemistry AS CR, Prague, Czech Republic
| | - L Maletínská
- Institute of Organic Chemistry and Biochemistry AS CR, Prague, Czech Republic
| | - J Zicha
- Institute of Physiology AS CR, Prague, Czech Republic
| | - J Kuneš
- Institute of Physiology AS CR, Prague, Czech Republic; Institute of Organic Chemistry and Biochemistry AS CR, Prague, Czech Republic.
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14
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Kuneš J, Geffroy D. Spontaneous Spin Textures in Multiorbital Mott Systems. Phys Rev Lett 2016; 116:256403. [PMID: 27391736 DOI: 10.1103/physrevlett.116.256403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Indexed: 06/06/2023]
Abstract
Spin textures in k-space arising from spin-orbit coupling in noncentrosymmetric crystals find numerous applications in spintronics. We present a mechanism that leads to the appearance of k-space spin texture due to spontaneous symmetry breaking driven by electronic correlations. Using dynamical mean-field theory we show that doping a spin-triplet excitonic insulator provides a means of creating new thermodynamic phases with unique properties. The numerical results are interpreted using analytic calculations within a generalized double-exchange framework.
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Affiliation(s)
- J Kuneš
- Institute of Physics, The Czech Academy of Sciences, Na Slovance 2, 182 21 Praha 8, Czech Republic
| | - D Geffroy
- Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic
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15
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Wadley P, Howells B, Železný J, Andrews C, Hills V, Campion RP, Novák V, Olejník K, Maccherozzi F, Dhesi SS, Martin SY, Wagner T, Wunderlich J, Freimuth F, Mokrousov Y, Kuneš J, Chauhan JS, Grzybowski MJ, Rushforth AW, Edmonds KW, Gallagher BL, Jungwirth T. Electrical switching of an antiferromagnet. Science 2016; 351:587-90. [PMID: 26841431 DOI: 10.1126/science.aab1031] [Citation(s) in RCA: 297] [Impact Index Per Article: 37.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 01/04/2016] [Indexed: 11/02/2022]
Abstract
Antiferromagnets are hard to control by external magnetic fields because of the alternating directions of magnetic moments on individual atoms and the resulting zero net magnetization. However, relativistic quantum mechanics allows for generating current-induced internal fields whose sign alternates with the periodicity of the antiferromagnetic lattice. Using these fields, which couple strongly to the antiferromagnetic order, we demonstrate room-temperature electrical switching between stable configurations in antiferromagnetic CuMnAs thin-film devices by applied current with magnitudes of order 10(6) ampere per square centimeter. Electrical writing is combined in our solid-state memory with electrical readout and the stored magnetic state is insensitive to and produces no external magnetic field perturbations, which illustrates the unique merits of antiferromagnets for spintronics.
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Affiliation(s)
- P Wadley
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK.
| | - B Howells
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
| | - J Železný
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 162 00 Praha 6, Czech Republic. Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16 Prague 2, Czech Republic
| | - C Andrews
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
| | - V Hills
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
| | - R P Campion
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
| | - V Novák
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 162 00 Praha 6, Czech Republic
| | - K Olejník
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 162 00 Praha 6, Czech Republic
| | - F Maccherozzi
- Diamond Light Source, Chilton, Didcot, Oxfordshire, OX11 0DE, UK
| | - S S Dhesi
- Diamond Light Source, Chilton, Didcot, Oxfordshire, OX11 0DE, UK
| | - S Y Martin
- Hitachi Cambridge Laboratory, J. J. Thomson Avenue, Cambridge CB3 0HE, UK
| | - T Wagner
- Hitachi Cambridge Laboratory, J. J. Thomson Avenue, Cambridge CB3 0HE, UK. Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB3 0HE, UK
| | - J Wunderlich
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 162 00 Praha 6, Czech Republic. Hitachi Cambridge Laboratory, J. J. Thomson Avenue, Cambridge CB3 0HE, UK
| | - F Freimuth
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany
| | - Y Mokrousov
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany
| | - J Kuneš
- Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, 182 21 Praha 8, Czech Republic
| | - J S Chauhan
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
| | - M J Grzybowski
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK. Institute of Physics, Polish Academy of Sciences, al. Lotnikow 32/46, PL-02-668 Warsaw, Poland
| | - A W Rushforth
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
| | - K W Edmonds
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
| | - B L Gallagher
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
| | - T Jungwirth
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 162 00 Praha 6, Czech Republic. School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
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16
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Zicha J, Dobešová Z, Zídek V, Silhavý J, Simáková M, Mlejnek P, Vaněčková I, Kuneš J, Pravenec M. Pharmacogenetic analysis of captopril effects on blood pressure: possible role of the Ednrb (endothelin receptor type B) candidate gene. Physiol Res 2015; 63:263-5. [PMID: 24779608 DOI: 10.33549/physiolres.932732] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The objective of the current study was to search for genetic determinants associated with antihypertensive effects of angiotensin-converting enzyme (ACE) inhibitor captopril. Linkage and correlation analyses of captopril-induced effects on blood pressure (BP) with renal transcriptome were performed in the BXH/HXB recombinant inbred (RI) strains derived from spontaneously hypertensive rat (SHR) and Brown Norway (BN-Lx) progenitors. Variability of blood pressure lowering effects of captopril among RI strains was continuous suggesting a polygenic mode of inheritance. Linkage analysis of captopril-induced BP effects revealed a significant quantitative trait locus (QTL) on chromosome 15. This QTL colocalized with cis regulated expression QTL (eQTL) for the Ednrb (endothelin receptor type B) gene in the kidney (SHR allele was associated with increased renal expression) and renal expression of Ednrb correlated with captopril-induced BP effects. These results suggest that blood pressure lowering effects of ACE inhibitor captopril may be modulated by the variants at the Ednrb locus.
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Affiliation(s)
- J Zicha
- Institute of Physiology Academy of Sciences of the Czech Republic, Prague, Czech Republic.
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17
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Hošťálková A, Kuneš J, Macáková K, Hrabinová M, Opletal L. Alkaloids from hydrastidis canadensis and their cholinesterase and prolyl oligopeptidase inhibitory. Ceska Slov Farm 2015; 64:41-43. [PMID: 26084651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
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Zicha J, Behuliak M, Pintérová M, Bencze M, Kuneš J, Vaněčková I. The interaction of calcium entry and calcium sensitization in the control of vascular tone and blood pressure of normotensive and hypertensive rats. Physiol Res 2014; 63:S19-27. [PMID: 24564658 DOI: 10.33549/physiolres.932639] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Increased systemic vascular resistance is responsible for blood pressure (BP) elevation in most forms of human or experimental hypertension. The enhanced contractility of structurally remodeled resistance arterioles is mediated by enhanced calcium entry (through L type voltage-dependent calcium channels - L-VDCC) and/or augmented calcium sensitization (mediated by RhoA/Rho kinase pathway). It is rather difficult to evaluate separately the role of these two pathways in BP control because BP response to the blockade of either pathway is always dependent on the concomitant activity of the complementary pathway. Moreover, vasoconstrictor systems enhance the activity of both pathways, while vasodilators attenuate them. The basal fasudil-sensitive calcium sensitization determined in rats deprived of endogenous renin-angiotensin system (RAS) and sympathetic nervous system (SNS) in which calcium entry was dose-dependently increased by L-VDCC opener BAY K8644, is smaller in spontaneously hypertensive rats (SHR) than in normotensive Wistar-Kyoto (WKY) rats. In contrast, if endogenous RAS and SNS were present in intact rats, fasudil caused a greater BP fall in SHR than WKY rats. Our in vivo experiments indicated that the endogenous pressor systems (RAS and SNS) augment calcium sensitization mediated by RhoA/Rho kinase pathway, whereas the endogenous vasodilator systems (such as nitric oxide) attenuate this pathway. However, the modulation of calcium entry and calcium sensitization by nitric oxide is strain-dependent because NO deficiency significantly augments low calcium entry in WKY and low calcium sensitization in SHR. Further in vivo and in vitro experiments should clarify the interrelationships between endogenous vasoactive systems and the contribution of calcium entry and/or calcium sensitization to BP maintenance in various forms of experimental hypertension.
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Affiliation(s)
- J Zicha
- Department of Experimental Hypertension, Institute of Physiology Academy of Sciences of the Czech Republic, Prague, Czech Republic.
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19
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Marti X, Fina I, Frontera C, Liu J, Wadley P, He Q, Paull RJ, Clarkson JD, Kudrnovský J, Turek I, Kuneš J, Yi D, Chu JH, Nelson CT, You L, Arenholz E, Salahuddin S, Fontcuberta J, Jungwirth T, Ramesh R. Room-temperature antiferromagnetic memory resistor. Nat Mater 2014; 13:367-374. [PMID: 24464243 DOI: 10.1038/nmat3861] [Citation(s) in RCA: 151] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Accepted: 12/10/2013] [Indexed: 06/03/2023]
Abstract
The bistability of ordered spin states in ferromagnets provides the basis for magnetic memory functionality. The latest generation of magnetic random access memories rely on an efficient approach in which magnetic fields are replaced by electrical means for writing and reading the information in ferromagnets. This concept may eventually reduce the sensitivity of ferromagnets to magnetic field perturbations to being a weakness for data retention and the ferromagnetic stray fields to an obstacle for high-density memory integration. Here we report a room-temperature bistable antiferromagnetic (AFM) memory that produces negligible stray fields and is insensitive to strong magnetic fields. We use a resistor made of a FeRh AFM, which orders ferromagnetically roughly 100 K above room temperature, and therefore allows us to set different collective directions for the Fe moments by applied magnetic field. On cooling to room temperature, AFM order sets in with the direction of the AFM moments predetermined by the field and moment direction in the high-temperature ferromagnetic state. For electrical reading, we use an AFM analogue of the anisotropic magnetoresistance. Our microscopic theory modelling confirms that this archetypical spintronic effect, discovered more than 150 years ago in ferromagnets, is also present in AFMs. Our work demonstrates the feasibility of fabricating room-temperature spintronic memories with AFMs, which in turn expands the base of available magnetic materials for devices with properties that cannot be achieved with ferromagnets.
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Affiliation(s)
- X Marti
- 1] Department of Materials Science and Engineering and Department of Physics, University of California, Berkeley, California 94720, USA [2] Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, 12116 Praha 2, Czech Republic [3] Institute of Physics ASCR, v.v.i., Cukrovarnická 10, 162 53 Praha 6, Czech Republic
| | - I Fina
- 1] Institut de Ciència de Materials de Barcelona, ICMAB-CSIC, Campus UAB, Bellaterra E-08193, Spain [2] Max Planck Institute of Microstructure Physics, Weinberg 2, Halle D-06120, Germany
| | - C Frontera
- Institut de Ciència de Materials de Barcelona, ICMAB-CSIC, Campus UAB, Bellaterra E-08193, Spain
| | - Jian Liu
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - P Wadley
- 1] Institute of Physics ASCR, v.v.i., Cukrovarnická 10, 162 53 Praha 6, Czech Republic [2] School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
| | - Q He
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - R J Paull
- Department of Materials Science and Engineering and Department of Physics, University of California, Berkeley, California 94720, USA
| | - J D Clarkson
- Department of Materials Science and Engineering and Department of Physics, University of California, Berkeley, California 94720, USA
| | - J Kudrnovský
- Institute of Physics ASCR, v.v.i., Na Slovance 2, 182 21 Praha 8, Czech Republic
| | - I Turek
- 1] Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, 12116 Praha 2, Czech Republic [2] Institute of Physics of Materials ASCR, v.v.i., Zizkova 22, Brno 616 62, Czech Republic
| | - J Kuneš
- Institute of Physics ASCR, v.v.i., Cukrovarnická 10, 162 53 Praha 6, Czech Republic
| | - D Yi
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - J-H Chu
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - C T Nelson
- National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - L You
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, California 94720, USA
| | - E Arenholz
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - S Salahuddin
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, California 94720, USA
| | - J Fontcuberta
- Institut de Ciència de Materials de Barcelona, ICMAB-CSIC, Campus UAB, Bellaterra E-08193, Spain
| | - T Jungwirth
- 1] Institute of Physics ASCR, v.v.i., Cukrovarnická 10, 162 53 Praha 6, Czech Republic [2] School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
| | - R Ramesh
- 1] Department of Materials Science and Engineering and Department of Physics, University of California, Berkeley, California 94720, USA [2] Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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20
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Pintérová M, Behuliak M, Kuneš J, Zicha J. Involvement of BKCa and KV potassium channels in cAMP-induced vasodilatation: their insufficient function in genetic hypertension. Physiol Res 2014; 63:275-85. [PMID: 24397812 DOI: 10.33549/physiolres.932718] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Spontaneously hypertensive rats (SHR) are characterized by enhanced sympathetic vasoconstriction, whereas their vasodilator mechanisms are relatively attenuated compared to their high BP. The objective of our in vivo study was to evaluate whether the impaired function of BKCa and/or KV channels is responsible for abnormal cAMP-induced vasodilatation in genetic hypertension. Using conscious SHR and normotensive WKY rats we have shown that under the basal conditions cAMP overproduction elicited by the infusion of beta-adrenoceptor agonist (isoprenaline) caused a more pronounced decrease of baseline blood pressure (BP) in SHR compared to WKY rats. Isoprenaline infusion prevented BP rises induced by acute NO synthase blockade in both strains and it also completely abolished the fully developed BP response to NO synthase blockade. These cAMP-induced vasodilator effects were diminished by the inhibition of either BKCa or KV channels in SHR but simultaneous blockade of both K(+) channel types was necessary in WKY rats. Under basal conditions, the vasodilator action of both K(+) channels was enhanced in SHR compared to WKY rats. However, the overall contribution of K(+) channels to cAMP-induced vasodilator mechanisms is insufficient in genetic hypertension since a concurrent activation of both K(+) channels by cAMP overproduction is necessary for the prevention of BP rise elicited by acute NO/cGMP deficiency in SHR. This might be caused by less effective activation of these K(+) channels by cAMP in SHR. In conclusion, K(+) channels seem to have higher activity in SHR, but their vasodilator action cannot match sufficiently the augmented vasoconstriction in this hypertensive strain.
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Affiliation(s)
- M Pintérová
- Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
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21
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Novák P, Knížek K, Maryško M, Jirák Z, Kuneš J. Crystal field and magnetism of Pr³⁺ and Nd³⁺ ions in orthorhombic perovskites. J Phys Condens Matter 2013; 25:446001. [PMID: 24113417 DOI: 10.1088/0953-8984/25/44/446001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Fifteen parameters characterizing the crystal field of rare-earth ions in the RMO3 perovskites (R=Pr, Nd, M=Ga, Co) are calculated using a first-principles electronic structure and the Wannier projection. The method contains a single adjustable parameter that characterizes the hybridization of R(4f) states with the states of oxygen ligands. Subsequently the energy levels and magnetic moments of the trivalent R ion are determined by diagonalization of an effective Hamiltonian which, besides the crystal field, contains the 4f electron-electron repulsion, spin-orbit coupling and interaction with magnetic field. In the Ga compounds the energy levels of the ground multiplet agree within a few meV with those determined experimentally by other authors. For all four compounds in question the temperature dependence of magnetic susceptibility is measured on polycrystalline samples and compared with the results of calculation. For NdGaO3 the theory is also compared with the magnetic measurements on a single crystal presented by Luis et al (1998 Phys. Rev. B 58 798). Good agreement between the experiment and theory is found.
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Affiliation(s)
- P Novák
- Institute of Physics of ASCR, Cukrovarnická 10, 162 00 Prague 6, Czech Republic
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22
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Vaněčková I, Vokurková M, Rauchová H, Dobešová Z, Pecháňová O, Kuneš J, Vorlíček J, Zicha J. Chronic antioxidant therapy lowers blood pressure in adult but not in young Dahl salt hypertensive rats: the role of sympathetic nervous system. Acta Physiol (Oxf) 2013; 208:340-9. [PMID: 23480535 DOI: 10.1111/apha.12092] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 12/02/2012] [Accepted: 03/04/2013] [Indexed: 12/24/2022]
Abstract
AIM It is well-known that salt hypertension is associated with increased oxidative stress. Since the development of salt hypertension is age-dependent, we were interested whether young and adult salt hypertensive Dahl rats differ in oxidative stress level and/or in the effects of chronic antioxidant therapy on blood pressure (BP) level and on the participation of particular vasoconstrictor/vasodilator systems in BP maintenance. METHODS Young (5-week-old) and adult (12-week-old) salt-sensitive (Dahl-S) male rats were fed high-salt diet (5% NaCl) and drank tempol solution (2 mm) for 5 weeks. BP was monitored with radiotelemetry and vasoconstrictor/vasodilator balance was evaluated at the end of experiment. Moreover, NO synthase activity, superoxide production and lipoperoxidation were determined in heart, kidney and aorta in separate subgroups of Dahl rats. RESULTS Tempol treatment had quite opposite BP effects in young and adult Dahl-S rats. While it tended to increase BP in young salt hypertensive Dahl-S rats, it significantly lowered BP in the adult ones due to reduced sympathetic vasoconstriction. Importantly, high salt intake substantially reduced NO synthase activity in heart and kidney, and markedly increased superoxide production in kidneys and aorta of adult Dahl-S rats in which BP correlated positively with superoxide production in thoracic aorta and lipoperoxidation in kidneys. CONCLUSION Chronic antioxidant therapy lowered BP only in adult salt hypertensive Dahl-S rats in which superoxide levels were increased in both kidneys and aorta. Blood pressure reduction induced by chronic tempol treatment is related to attenuated sympathetic vasoconstriction rather than to augmented NO-dependent vasodilatation.
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Affiliation(s)
- I. Vaněčková
- Institute of Physiology V.V.I; Academy of Sciences of the Czech Republic; Prague; Czech Republic
| | - M. Vokurková
- Institute of Physiology V.V.I; Academy of Sciences of the Czech Republic; Prague; Czech Republic
| | - H. Rauchová
- Institute of Physiology V.V.I; Academy of Sciences of the Czech Republic; Prague; Czech Republic
| | - Z. Dobešová
- Institute of Physiology V.V.I; Academy of Sciences of the Czech Republic; Prague; Czech Republic
| | - O. Pecháňová
- Institute of Normal and Pathological Physiology and Centre of Excellence for Cardiovascular Research; Slovak Academy of Sciences; Bratislava; Slovak Republic
| | - J. Kuneš
- Institute of Physiology V.V.I; Academy of Sciences of the Czech Republic; Prague; Czech Republic
| | - J. Vorlíček
- Institute of Physiology V.V.I; Academy of Sciences of the Czech Republic; Prague; Czech Republic
| | - J. Zicha
- Institute of Physiology V.V.I; Academy of Sciences of the Czech Republic; Prague; Czech Republic
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Abstract
Hypertension is one of the major risk factor of cardiovascular diseases, but after a century of clinical and basic research, the discrete etiology of this disease is still not fully understood. One reason is that blood pressure is a quantitative trait with multifactorial determination. Numerous genes, environmental factors as well as epigenetic factors should be considered. There is no doubt that although the full manifestation of hypertension and other cardiovascular diseases usually occurs predominantly in adulthood and/or senescence, the roots can be traced back to early ontogeny. The detailed knowledge of the ontogenetic changes occurring in the cardiovascular system of experimental animals during particular critical periods (developmental windows) could help to solve this problem in humans and might facilitate the age-specific prevention of human hypertension. We thus believe that this approach might contribute to the reduction of cardiovascular morbidity among susceptible individuals in the future.
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Affiliation(s)
- J Kuneš
- Centre for Cardiovascular Research, Prague, Czech Republic.
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Zicha J, Dobešová Z, Vokurková M, Rauchová H, Hojná S, Kadlecová M, Behuliak M, Vaněčková I, Kuneš J. Age-dependent salt hypertension in Dahl rats: fifty years of research. Physiol Res 2013; 61:S35-S87. [PMID: 22827876 DOI: 10.33549/physiolres.932363] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Fifty years ago, Lewis K. Dahl has presented a new model of salt hypertension - salt-sensitive and salt-resistant Dahl rats. Twenty years later, John P. Rapp has published the first and so far the only comprehensive review on this rat model covering numerous aspects of pathophysiology and genetics of salt hypertension. When we summarized 25 years of our own research on Dahl/Rapp rats, we have realized the need to outline principal abnormalities of this model, to show their interactions at different levels of the organism and to highlight the ontogenetic aspects of salt hypertension development. Our attention was focused on some cellular aspects (cell membrane function, ion transport, cell calcium handling), intra- and extrarenal factors affecting renal function and/or renal injury, local and systemic effects of renin-angiotensin-aldosterone system, endothelial and smooth muscle changes responsible for abnormal vascular contraction or relaxation, altered balance between various vasoconstrictor and vasodilator systems in blood pressure maintenance as well as on the central nervous and peripheral mechanisms involved in the regulation of circulatory homeostasis. We also searched for the age-dependent impact of environmental and pharmacological interventions, which modify the development of high blood pressure and/or organ damage, if they influence the salt-sensitive organism in particular critical periods of development (developmental windows). Thus, severe self-sustaining salt hypertension in young Dahl rats is characterized by pronounced dysbalance between augmented sympathetic hyperactivity and relative nitric oxide deficiency, attenuated baroreflex as well as by a major increase of residual blood pressure indicating profound remodeling of resistance vessels. Salt hypertension development in young but not in adult Dahl rats can be attenuated by preventive increase of potassium or calcium intake. On the contrary, moderate salt hypertension in adult Dahl rats is attenuated by superoxide scavenging or endothelin-A receptor blockade which do not affect salt hypertension development in young animals.
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Affiliation(s)
- J Zicha
- Centre for Cardiovascular Research, Prague, Czech Republic.
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Augustinský P, Křápek V, Kuneš J. Doping induced spin state transition in LaCoO3: dynamical mean-field study. Phys Rev Lett 2013; 110:267204. [PMID: 23848917 DOI: 10.1103/physrevlett.110.267204] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 04/13/2013] [Indexed: 06/02/2023]
Abstract
Hole and electron doped LaCoO3 is studied using dynamical mean-field theory. The one-particle spectra are analyzed and compared to the available experimental data, in particular the x-ray absorption spectra. Analyzing the temporal spin-spin correlation functions we find the atomic intermediate spin state is not important for the observed Curie-Weiss susceptibility. Contrary to the commonly held view about the roles played by the t2g and eg electrons we find narrow quasiparticle bands of t2g character crossing the Fermi level accompanied by strongly damped eg excitations.
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Affiliation(s)
- P Augustinský
- Theoretical Physics III, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg, D-86135 Augsburg, Germany
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26
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Kuneš J, Křápek V, Parragh N, Sangiovanni G, Toschi A, Kozhevnikov AV. Spin state of negative charge-transfer material SrCoO(3). Phys Rev Lett 2012; 109:117206. [PMID: 23005672 DOI: 10.1103/physrevlett.109.117206] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Indexed: 06/01/2023]
Abstract
We employ the combination of the density functional theory and the dynamical mean-field theory to investigate the electronic structure and magnetic properties of SrCoO(3), monocrystals of which were prepared recently. Our calculations lead to a ferromagnetic metal in agreement with experiment. We find that, contrary to some suggestions, the local moment in SrCoO(3) does not arise from intermediate spin state, but is a result of coherent superposition of many different atomic states. We discuss how the attribution of magnetic response to different atomic states in solids with local moments can be quantified.
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Affiliation(s)
- J Kuneš
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, Praha 6, 162 53, Czech Republic
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Zicha J, Dobešová Z, Kuneš J, Vaněčková I. Chronic endothelin A receptor blockade attenuates contribution of sympathetic nervous system to salt hypertension development in adult but not in young Dahl rats. Acta Physiol (Oxf) 2012; 205:124-32. [PMID: 22463612 DOI: 10.1111/j.1748-1716.2012.02395.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIM Endothelin-1 (ET-1) plays an important role in the pathogenesis of salt-dependent forms of hypertension in adult rats, but its participation in salt hypertension elicited in immature rats is still unknown. Therefore, we compared ET-1 role in the development or the maintenance of salt hypertension induced in young (4-week-old) or adult (12-week-old) Dahl rats. METHODS The contribution of pressor ET-1 effects to the maintenance of high blood pressure (BP) was studied using acute injection of ET(A) receptor antagonist ambrisentan (BSF 208075, 1 mg kg(-1) iv) to young or adult rats with established salt hypertension. Furthermore, using chronic ambrisentan treatment (30 mg kg(-1) day(-1) in the drinking fluid during 5 weeks of high salt intake), we investigated the age-dependent involvement of ET(A) receptors in salt hypertension development in these two age groups. RESULTS Acute ET(A) receptor blockade lowered BP in both age groups of salt hypertensive Dahl rats more than in rats fed a low-salt diet (but without any age-dependent difference). Chronic ET(A) receptor blockade strongly attenuated the development of salt hypertension and cardiac hypertrophy in adult rats, but it had no significant effects on salt hypertension in young animals. Pronounced BP reduction induced in adult salt hypertensive rats by chronic ambrisentan treatment was attributed to attenuated sympathetic BP component, without changes in nitric oxide (NO)-dependent BP regulation. In contrast, chronic ambrisentan treatment of young animals did not modify sympathetic BP component but substantially attenuated NO-dependent vasodilatation. CONCLUSIONS ET(A) receptor-mediated ET-1 effects play an important role in salt hypertension of adult but not young Dahl rats.
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Affiliation(s)
- J. Zicha
- Center for Experimental Cardiovascular Research; Institute of Physiology, Academy of Sciences of the Czech Republic; Prague; Czech Republic
| | - Z. Dobešová
- Center for Experimental Cardiovascular Research; Institute of Physiology, Academy of Sciences of the Czech Republic; Prague; Czech Republic
| | - J. Kuneš
- Center for Experimental Cardiovascular Research; Institute of Physiology, Academy of Sciences of the Czech Republic; Prague; Czech Republic
| | - I. Vaněčková
- Center for Experimental Cardiovascular Research; Institute of Physiology, Academy of Sciences of the Czech Republic; Prague; Czech Republic
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Arita R, Kuneš J, Kozhevnikov AV, Eguiluz AG, Imada M. Ab initio studies on the interplay between spin-orbit interaction and Coulomb correlation in Sr2IrO4 and Ba2IrO4. Phys Rev Lett 2012; 108:086403. [PMID: 22463548 DOI: 10.1103/physrevlett.108.086403] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Indexed: 05/31/2023]
Abstract
Ab initio analyses of A(2)IrO(4) (A=Sr,Ba) are presented. Effective Hubbard-type models for Ir 5d t(2g) manifolds downfolded from the global band structure are solved based on the dynamical mean-field theory. The results for A=Sr and Ba correctly reproduce paramagnetic metals undergoing continuous transitions to insulators below the Néel temperature T(N). These compounds are classified not into Mott insulators but into Slater insulators. However, the insulating gap opens by a synergy of the Néel order and significant band renormalization, which is also manifested by a 2D bad metallic behavior in the paramagnetic phase near the quantum criticality.
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Affiliation(s)
- R Arita
- Department of Applied Physics, University of Tokyo, Tokyo, Japan
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Zicha J, Dobešová Z, Kuneš J, Vaněčková I. Chronic endothelin A receptor blockade attenuates contribution of sympathetic nervous system to salt hypertension development in adult but not in young Dahl rats. Acta Physiol (Oxf) 2012. [DOI: 10.1111/j.1748-1716.2011.02395.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- J. Zicha
- Center for Experimental Cardiovascular Research; Institute of Physiology, Academy of Sciences of the Czech Republic; Prague; Czech Republic
| | - Z. Dobešová
- Center for Experimental Cardiovascular Research; Institute of Physiology, Academy of Sciences of the Czech Republic; Prague; Czech Republic
| | - J. Kuneš
- Center for Experimental Cardiovascular Research; Institute of Physiology, Academy of Sciences of the Czech Republic; Prague; Czech Republic
| | - I. Vaněčková
- Center for Experimental Cardiovascular Research; Institute of Physiology, Academy of Sciences of the Czech Republic; Prague; Czech Republic
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Abstract
Essential hypertension is a multifactorial disorder which belongs to the main risk factors responsible for renal and cardiovascular complications. This review is focused on the experimental research of neural and vascular mechanisms involved in the high blood pressure control. The attention is paid to the abnormalities in the regulation of sympathetic nervous system activity and adrenoceptor alterations as well as the changes of membrane and intracellular processes in the vascular smooth muscle cells of spontaneously hypertensive rats. These abnormalities lead to increased vascular tone arising from altered regulation of calcium influx through L-VDCC channels, which has a crucial role for excitation-contraction coupling, as well as for so-called "calcium sensitization" mediated by the RhoA/Rho-kinase pathway. Regulation of both pathways is dependent on the complex interplay of various vasodilator and vasoconstrictor stimuli. Two major antagonistic players in the regulation of blood pressure, i.e. sympathetic nervous system (by stimulation of adrenoceptors coupled to stimulatory and inhibitory G proteins) and nitric oxide (by cGMP signaling pathway), elicit their actions via the control of calcium influx through L-VDCC. However, L-type calcium current can also be regulated by the changes in membrane potential elicited by the activation of potassium channels, the impaired function of which was detected in hypertensive animals. The dominant role of enhanced calcium influx in the pathogenesis of high blood pressure of genetically hypertensive animals is confirmed not only by therapeutic efficacy of calcium antagonists but especially by the absence of hypertension in animals in which L-type calcium current was diminished by pertussis toxin-induced inactivation of inhibitory G proteins. Although there is considerable information on the complex neural and vascular alterations in rats with established hypertension, the detailed description of their appearance during the induction of hypertension is still missing.
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Affiliation(s)
- M Pintérová
- Cardiovascular Research Center and Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
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Zicha J, Dobešová Z, Behuliak M, Kuneš J, Vaněčková I. Preventive dietary potassium supplementation in young salt-sensitive Dahl rats attenuates development of salt hypertension by decreasing sympathetic vasoconstriction. Acta Physiol (Oxf) 2011; 202:29-38. [PMID: 21199401 DOI: 10.1111/j.1748-1716.2010.02248.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIM Increased potassium intake attenuates the development of salt-dependent hypertension, but the detailed mechanisms of blood pressure (BP) reduction are still unclear. The aims of our study were (i) to elucidate these mechanisms, (ii) to compare preventive potassium effects in immature and adult animals and (iii) to evaluate the therapeutic effects of dietary potassium supplementation in rats with established salt hypertension. METHODS Young (4-week-old) and adult (24-week-old) female salt-sensitive Dahl rats were fed a high-salt diet (5% NaCl) or a high-salt diet supplemented with 3% KCl for 5 weeks. The participation of vasoconstrictor (renin-angiotensin and sympathetic nervous systems) and vasodilator systems [prostanoids, Ca(2+) -activated K(+) channels, nitric oxide (NO)] was evaluated using a sequential blockade of these systems. RESULTS Preventive potassium supplementation attenuated the development of severe salt hypertension in young rats, whereas it had no effects on BP in adult rats with moderate hypertension. Enhanced sympathetic vasoconstriction was responsible for salt hypertension in young rats and its attenuation for potassium-induced BP reduction. Conversely, neither salt hypertension nor its potassium-induced attenuation were associated with significant changes of the vasodilator systems studied. The relative deficiency of vasodilator action of NO and Ca(2+) -activated K(+) channels in salt hypertensive Dahl rats was not improved by potassium supplementation. CONCLUSIONS The attenuation of enhanced sympathetic vasoconstriction is the principal mechanism of antihypertensive action exerted by preventive potassium supplementation in immature Dahl rats. Dietary potassium supplementation has no preventive effects on BP in adult salt-loaded animals or no therapeutic effects on established salt hypertension in young rats.
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Affiliation(s)
- J Zicha
- Cardiovascular Research Center, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
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Hojná S, Kuneš J, Zicha J. Alterations of NO synthase isoforms in brain and kidney of rats with genetic and salt hypertension. Physiol Res 2010; 59:997-1009. [DOI: 10.33549/physiolres.932064] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Both brain and peripheral nitric oxide (NO) play a role in the
control of blood pressure and circulatory homeostasis. Central NO
production seems to counteract angiotensin II-induced
enhancement of sympathetic tone. The aim of our study was to
evaluate NO synthase (NOS) activity and protein expression of its
three isoforms – neuronal (nNOS), endothelial NOS (eNOS) and
inducible (iNOS) – in two brain regions involved in blood pressure
control (diencephalon and brainstem) as well as in the kidney of
young adult rats with either genetic (12-week-old SHR) or saltinduced hypertension (8-week-old Dahl rats). We have demonstrated reduced nNOS and iNOS expression in brainstem of both hypertensive models. In SHR this abnormality was
accompanied by attenuated NOS activity and was corrected by
chronic captopril treatment which prevented the development of
genetic hypertension. In salt hypertensive Dahl rats nNOS and
iNOS expression was also decreased in the diencephalon where
neural structures important for salt hypertension development
are located. As far as peripheral NOS activity and expression is
concerned, renal eNOS expression was considerably reduced in
both genetic and salt-induced hypertension. In conclusions, we
disclosed similar changes of NO system in the brainstem (but not
in the diencephalon) of rats with genetic and salt-induced
hypertension. Decreased nNOS expression was associated with
increased blood pressure due to enhanced sympathetic tone.
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Zicha J, Vaněčková I, Kuneš J. Systems analysis in hypertension: complementary role of physiologists and geneticists. Physiol Res 2010; 59:837-839. [PMID: 21208015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023] Open
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Anisimov VI, Korotin DM, Korotin MA, Kozhevnikov AV, Kuneš J, Shorikov AO, Skornyakov SL, Streltsov SV. Coulomb repulsion and correlation strength in LaFeAsO from density functional and dynamical mean-field theories. J Phys Condens Matter 2009; 21:075602. [PMID: 21817332 DOI: 10.1088/0953-8984/21/7/075602] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The LDA+DMFT (local density approximation combined with dynamical mean-field theory) computation scheme has been used to calculate spectral properties of LaFeAsO-the parent compound of the new high-T(c) iron oxypnictides. The average Coulomb repulsion [Formula: see text] and Hund's exchange J parameters for iron 3d electrons were calculated using the first-principles constrained density functional theory scheme in the Wannier functions formalism. Resulting values strongly depend on the number of states taken into account in the calculations: when the full set of O-2p, As-4p and Fe-3d orbitals and the corresponding bands are included, the interaction parameters [Formula: see text] eV and J = 0.8 eV are obtained. In contrast, when the basis set is restricted to the Fe-3d orbitals and bands only, the calculation gives much smaller values of [Formula: see text] eV, J = 0.5 eV. Nevertheless, DMFT calculations with both parameter sets and the corresponding basis sets result in a weakly correlated electronic structure that is in agreement with the experimental x-ray and photoemission spectra.
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Affiliation(s)
- V I Anisimov
- Institute of Metal Physics, Russian Academy of Sciences, 620041 Yekaterinburg GSP-170, Russia
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35
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Hubáček JA, Adámková V, Vrablík M, Kadlecová M, Zicha J, Kuneš J, Piťha J, Suchánek P, Poledne R. Apolipoprotein A5 in health and disease. Physiol Res 2009; 58 Suppl 2:S101-S110. [DOI: 10.33549/physiolres.931911] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
High plasma levels of triglycerides (TG) are an independent risk
factor in the development of cardiovascular disease, with about
50 % of the final levels being determined genetically.
Apolipoprotein A5 (APOA5) is the last discovered member of the
apolipoprotein APOA1/C3/A4 gene cluster, found by comparative
sequencing analysis. The importance of APOA5 gene for
determination of plasma triglyceride levels has been suggested
after development of transgenic and knock-out mice (transgenic
mice displayed significantly reduced TG, whereas knock-out mice
had high TG). In Czech population, alleles C-1131 and Trp19 are
associated with elevated levels of plasma TG and higher risk of
myocardial infarction development. These alleles also play some
role in nutrigenetics and actigenetics of lifestyle interventions
leading to the plasma cholesterol changes as well as in the
pharmacogenetics of statin treatment. On the contrary, APOA5
mutations detected in Czech population did not show strict effect
on plasma TG levels. Val153 → Met variant exhibit the sexspecific effect of HDL-cholesterol levels. The suggested roles of
APOA5 variants in determination of the plasma remnant particles,
plasma concentrations of C-reactive protein or some
anthropometrical parameters were excluded.
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Čačányiová S, Kristek F, Kuneš J, Zicha J. The effects of pertussis toxin-treatment on integrated vasoactive response of vascular system in spontaneously hypertensive rats. Physiol Res 2008; 57:137-139. [DOI: 10.33549/physiolres.931576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
We investigated the effect of pertussis toxin (PTX) on
hypotensive response induced by acetylcholine (ACh) and
bradykinin (BK) and on noradrenaline (NA)-induced pressor
response in spontaneously hypertensive rats (SHR). Fifteenweek-old Wistar rats and age-matched SHR were used. Half of SHR received PTX (10 µg/kg/i.v.) and the experiments were performed 48 h later. After the anesthesia the right carotid artery
was cannulated in order to record blood pressure (BP). The
hypotensive response to ACh was enhanced in SHR compared to
Wistar rats. After pretreatment of SHR with PTX the hypotensive
response to ACh was reduced compared to untreated SHR and it
was also diminished in comparison to Wistar rats. Similarly, the
hypotensive response to BK was also decreased after PTX
pretreatment. The pressor response to NA was increased in SHR
compared to Wistar rats. NA-induced pressor response was
considerably decreased after PTX pretreatment compared to
untreated SHR. In conclusion, the enhancement of hypotensive
and pressor responses in SHR was abolished after PTX
pretreatment. Our results suggested that the activation of PTXsensitive inhibitory Gi proteins is involved in the regulation of
integrated vasoactive responses in SHR and PTX pretreatment
could be effectively used for modification of BP regulation in this
type of experimental hypertension.
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Cacányiová S, Cebová M, Kuneš J, Kristek F. Comparison of vascular function and structure of iliac artery in spontaneously hypertensive and hereditary hypertriglyceridemic rats. Physiol Res 2007; 55 Suppl 1:S73-S80. [PMID: 17177628 DOI: 10.33549/physiolres.930000.55.s1.73] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The aim of this study was to compare the vascular reactivity and morphology of iliac artery (IA) in adult spontaneously hypertensive rats (SHR) and hereditary hypertriglyceridemic (hHTG) rats. The isolated rings of iliac artery (IA) from Wistar rats (controls), SHR and hHTG rats were used for measurement of relaxant responses to acetylcholine (ACh) and contractile responses to noradrenaline (NA). Morphological changes of IA were measured using light microscopy. Systolic blood pressure (BP) measured by plethysmographic method was increased in SHR approximately by 88 % and in hHTG rats by 44 % compared to controls. BP increase was accompanied by cardiac hypertrophy. In both SHR and hHTG groups (experimental groups) reduced relaxation to ACh and enhanced maximal contraction and sensitivity to adrenergic stimuli were observed. The sensitivity to NA in SHR was higher also in comparison with hHTG. Geometry of IA in both experimental groups revealed increased wall thickness and wall cross-sectional area, in SHR even in comparison with hHTG. Inner diameter was decreased in both experimental groups. Thus, independently of etiology, hypertension in both models was connected with impaired endothelial function accompanied by structural alterations of IA. A degree of BP elevation was associated with arterial wall hypertrophy and increased contractile sensitivity.
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Affiliation(s)
- S Cacányiová
- Institute of Normal and Pathological Physiology, Slovak Academy of Sciences, Bratislava, Slovak Republic.
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Líšková S, Kuneš J, Zicha J. Nifedipine-sensitive vascular reactivity of femoral arteries in WKY: the effect of pertussis toxin pretreatment and endothelium removal. Physiol Res 2007; 56:663-666. [DOI: 10.33549/physiolres.931367] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Maintenance of norepinephrine (NE)-induced contraction is dependent on Ca(2+) influx through L-type voltage-dependent Ca(2+) channels (VDCC), which is opposed by nitric oxide. Adrenergic receptors are coupled with different G proteins, including inhibitory G proteins (Gi) that can be inactivated by pertussis toxin (PTX). Our study was aimed to investigate the effects of endothelium removal, PTX pretreatment and acute VDCC blockade by nifedipine on the contractions of femoral arteries stimulated by norepinephrine. We used 12-week-old male WKY, half of the rats being injected with PTX (10 microg/kg i.v., 48 h before the experiment), which considerably reduced their blood pressure (BP). Contractions of isolated arteries were measured using Mulvany-Halpern myograph. NE dose-response curves determined in femoral arteries from PTX-treated WKY rats were shifted to the right compared to those from control WKY. On the contrary, removal of endothelium augmented NE dose-response curves shifting them to the left. Acute VDCC blockade by nifedipine (10(-7) M) abolished all differences in NE dose-response curves which were dependent on the presence of either intact endothelium or functional Gi proteins because all NE dose-response curves were identical to the curve seen in vessels with intact endothelium from PTX-treated animals. We can conclude that BP reduction after PTX injection is accompanied by the attenuation of NE-induced contraction of femoral arteries irrespective of endothelium presence. Moreover, our data indicate that both vasodilator action of endothelium and Gi-dependent vasoconstrictor effect of norepinephrine operate via the control of Ca(2+) influx through VDCC.
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Čejka J, Železná B, Velek J, Zicha J, Kuneš J. LVV-hemorphin-7 lowers blood pressure in spontaneously hypertensive rats: radiotelemetry study. Physiol Res 2006. [DOI: 10.33549/physiolres.930728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023] Open
Abstract
Cardiovascular effects of LVV-hemorphin-7, a member of the family of fragments from beta-chain of human or bovine hemoglobin, were studied in conscious spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats by radiotelemetry. Intraperitoneal injection of hemorphin in a dose of 100 microg/kg significantly decreased blood pressure in SHR, whereas negligible effect was seen in normotensive WKY rats. Blood pressure changes were accompanied by reduction of heart rate. In conclusion, a direct effect of LVV-hemorphin-7 on blood pressure was demonstrated in SHR. These biologically active peptides could be involved in blood pressure regulation especially in hypertensive rats, but the precise mechanism should be elucidated.
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Císař P, Nobilis M, Vybíralová Z, Holčapek M, Kolářová L, Pour M, Kuneš J, Klimeš J. Corrigendum to “Disposition study of a new potential antineoplastic agent dimefluron in rats using high-performance liquid chromatography with ultraviolet and mass spectrometric detection” [J. Pharm. Biomed. Anal. 37 (2005) 1059–1071]. J Pharm Biomed Anal 2005. [DOI: 10.1016/j.jpba.2005.07.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Hojná S, Kadlecová M, Zicha J, Kuneš J. Polymorphism in Nos2 gene is absent in Prague colony of Dahl/Rapp salt-sensitive and salt-resistant rats. Physiol Res 2005. [DOI: 10.33549/physiolres.930000.54.201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
We have searched for polymorphism of inducible nitric oxide synthase gene (Nos2 gene) in the Prague colony of salt-sensitive and salt-resistant Dahl/Rapp rats. Specific primers were used to confirm previously described Nos2 gene polymorphism because this gene was suggested to be a potential candidate gene for genetic hypertension. Phenotyping (blood pressure, organ weight, plasma lipids) have confirmed the data known from other colonies of Dahl/Rapp rats. However, in our colony we were not able to find any Nos2 gene polymorphism between salt-sensitive and salt-resistant rats, which was previously described in animals from Harlan colony. Moreover, the genetic homogeneity of our salt-sensitive and salt-resistant rats in terms of Nos2 gene was the same as in the original Brookhaven colony of Dahl rats. This is surprising because our colony has been established from breeding pairs kindly provided by Prof. J.P. Rapp more than 15 years ago. It seems that the polymorphism found in Harlan colony could be the result of previous contamination or genetic drift during the breeding conditions specific for this colony.
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Kuneš J, Zicha J, Jelínek J. The role of chloride in deoxycorticosterone hypertension: selective sodium loading by diet or drinking fluid. Physiol Res 2004. [DOI: 10.33549/physiolres.930000.53.149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
To evaluate the role of chloride in the pathogenesis of salt-dependent deoxycorticosterone (DOC) hypertension, we studied young Wistar rats chronically loaded with sodium bicarbonate (NaHCO(3)) or sodium chloride (NaCl) which were administered either in the diet or in the drinking fluid. Selective sodium loading (without chloride) increased blood pressure (BP) in DOC-treated animals only if NaHCO(3) was provided in the diet. In contrast, no significant blood pressure changes were induced by DOC treatment in rats drinking NaHCO(3) solution. Hypernatremia and high plasma osmolality occurred only in rats drinking NaCl or NaHCO(3) solutions. Compared to great volume expansion in NaCl-loaded DOC-treated rats, the degree of extracellular fluid volume expansion (namely of its interstitial fraction) was substantially lower in both NaHCO(3)-loaded groups in which significant hypokalemia was observed. NaHCO(3)-drinking rats without significant blood pressure response to DOC treatment represented the only experimental group in which blood volume was not expanded. In conclusion, our data confirm previous observations that NaHCO(3) loading is less potent in eliciting DOC hypertension than NaCl loading, but blood pressure rise in rats fed NaHCO(3) diet clearly demonstrated that selective sodium loading could potentiate the development of DOC hypertension if NaHCO(3) is offered within the appropriate dietary regimen. The reasons for the failure of NaHCO(3)-drinking rats to elevate blood pressure in response to chronic mineralocorticoid treatment are not obvious. However, the absence of a significant plasma volume expansion together with hypernatremia and increased plasma osmolality suggest a considerable degree of dehydration in these animals which fail to increase their fluid consumption compared to water drinking rats.
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Kadlecová M, Čejka J, Zicha J, Kuneš J. Does Cd36 gene play a key role in disturbed glucose and fatty acid metabolism in Prague hypertensive hypertriglyceridemic rats? Physiol Res 2004. [DOI: 10.33549/physiolres.930000.53.265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Close links between hypertension, hypertriglyceridemia, insulin resistance and other symptoms of metabolic syndrome was demonstrated in humans and experimental animals. Quantitative trait loci for defects in glucose and fatty acid metabolism, hypertriglyceridemia and hypertension were mapped in spontaneously hypertensive rats (SHR) on chromosome 4 and defective Cd36 gene was identified in this region. Here we investigated the polymorphism of Cd36 gene in Prague hereditary hypertriglyceridemic (HTG) rats, which represent another model of genetic hypertension and metabolic syndrome. These animals were compared with NIH-derived SHR and two different normotensive control strains (WKY, LEW). In spite of the fact that HTG and SHR rats had similar metabolic disturbances, genotype analysis of PCR products has shown that Cd36 mutation was not present in HTG rats. In conclusion, we have revealed that defective Cd36 is probably a candidate gene for disorded fatty-acid metabolism, glucose intolerance and insulin resistance in NIH-derived SHR, but other genes might play a role in pathogenesis of metabolic syndrome in Prague hereditary hypertriglyceridemic rats. This is in accordance with the absence of defective Cd36 gene in original SHR from Japan.
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Kuneš J, Zicha J, Dobešová Z. ALTERED BALANCE OF SYMPATHETIC VASOCONSTRICTION AND NITRIC OXIDE-DEPENDENT VASODILATION IN SALT HYPERTENSION OF DAHL RATS. J Hypertens 2000. [DOI: 10.1097/00004872-200006001-00702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Vrána A, Kazdová L, Dobešová Z, Matějčková M, Kuneš J. Clustering and altered glucoregulation, hypertension, and lipoperoxidation in hereditary hypertriglyceridemic rats. Atherosclerosis 1995. [DOI: 10.1016/0021-9150(95)96501-i] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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