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3022. Alterations of NO synthase isoforms in brain and kidney of rats with genetic and salt hypertension
- Creator:
- Silvie Hojná, Jaroslav Kuneš, and Jan Zicha
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, ledviny, kidneys, brainstem, diencephalon, NO synthase, genetic hypertension, 14, and 612
- Language:
- English
- Description:
- Both brain and peripheral nitric oxide (NO) play a role in the control of blood pressure and circ ulatory 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 salt- induced 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 decrea sed 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 ex pression was associated with increased blood pressure due to enhanced sympathetic tone., S. Hojná, J. Kuneš, J. Zicha., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3023. Altered Balance of Vasoactive Systems in Experimental Hypertension: The Role of Relative NO Deficiency
- Creator:
- Kuneš, J., Hojná, S., Kadlecová, M., Dobešová, Z., Rauchová, H., Vokurková, M., Loukotová, J., Pecháňová, O., and Zicha, J.
- Type:
- article, model:article, and TEXT
- Subject:
- Nitric oxide, Sympathetic nervous system, Reactive oxygen species, Vasoactive system balance, nifedipinesensitive BP component, and Calcium influx
- Language:
- English
- Description:
- This review summarizes our findings concerning the altered balance of vasoactive systems (namely sympathetic nervous system and nitric oxide) in various forms of experimental hypertension – genetic hypertension (SHR, HTG rats), salt hypertension (Dahl rats) and NO-deficient hypertension (L-NAME-treated rats). An attempt is made to define relative NO deficiency (compared to the existing level of sympathetic vasoconstriction), to describe its possible causes and to evaluate particular indicators of its extent. A special attention is paid to reactive oxygen species, their interaction with NO metabolism, cell Ca2+ handling and blood pressure regulation. Our current effort is focused on the investigation of abnormal regulation of cytosolic Ca2+ levels in smooth muscle and endothelium of hypertensive animals. Such a research should cl arify the mechanisms by which genetic and/or environmental factors could chronically modify blood pressure level.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3024. Altered blood-brain barrier permeability and its effect on the distribution of Evans blue and sodium fluorescein in the rat brain applied by intracarotid injection
- Creator:
- Petr Kozler and Pokorný, J.
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, hematoencefalická bariéra, fluorescenční mikroskopie, blood-brain barrier, fluorescence microscopy, cellular edema, intravital dyes, 14, and 612
- Language:
- English
- Description:
- The aim was to study the blood-brain permeability according to the distribution in the rat brain of Evans blue (EB) and sodium fluorescein (NaFl) administered by an intracarotid injection. Eighteen animals were divided into six groups according to the state of the blood-brain barrier (BBB) at the moment when the dyes were being applied. In the first two groups, the BBB was intact, in groups 3 and 4 the barrier had been opened osmotically prior to the application of the dyes, and in groups 5 and 6 a cellular edema was induced by hyperhydration before administration of the dyes. The intracellular and extracellular distribution of the dyes was studied by fluorescence microscopy. The histological picture thus represented the morphological correlate of the way BBB permeability had been changed before the application of the dyes., P. Kozler, J. Pokorný., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3025. Altered expression of ORAI and STIM isoforms in activated human cardiac fibroblasts
- Creator:
- Čendula, Róbert, Chomaničová, Nikola, Adamičková, Adriana, Gažová, Andrea, Kyselovič, Ján, and Máťuš, Marek
- Format:
- počítač and online zdroj
- Type:
- model:article and TEXT
- Subject:
- fyziologie člověka, kardiologie, human physiology, cardiology, Human cardiac fibroblast (HCF), SOCE (Store-operated calcium entry), Orai, STIM, 14, and 612
- Language:
- English
- Description:
- Cardiac fibrotization is a well-known process characteristic of many cardiac pathological conditions. The key element is excessive activation of cardiac fibroblasts, their transdifferentiation into myofibroblasts, increased production, and accumulation of extracellular matrix proteins, resulting in cardiac stiffness. The exact cellular mechanisms and molecular components involved in the process are not fully elucidated, but the SOCE mechanism could play an important role. Its key molecules are the molecular sensor of calcium in ER/SR - STIM and the highly selective calcium channels Orai located in the plasma membrane. This study aims to evaluate selected SOCEassociated genes in the activation of HCF cell culture by several known substances (phenylephrine, isoprenaline) that represent cardiovascular overload. After cell cultivation, cell medium was collected to measure the soluble collagen content. From the harvested cells, qRT-PCR was performed to determine the mRNA levels of the corresponding genes. The activation of cells was based on changes in the relative expression of collagen genes as well as the collagen content in the medium of the cell culture. We detected an increase in the expression of the Orai2 isoform, a change in the Orai1/Orai3 ratio and also an increase in the expression of the STIM2 isoform. These results suggest an increased activation of the SOCE mechanism under stress conditions of fibroblasts, which supports the hypothesis of fibroblast activation in pathological processes by altering calcium homeostasis through the SOCE mechanism., Róbert Čendula, Nikola Chomaničová, Adriana Adamičková, Andrea Gažová, Ján Kyselovič, Marek Máťuš., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3026. Altered neural and vascular mechanisms in hypertension
- Creator:
- Mária Pintérová, Jaroslav Kuneš, and Jiří Zicha
- Format:
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, bílkoviny, sympatický nervový systém, krevní tlak, proteins, sympathetic nervous system, blood pressure, spontaneously hypertensive rats, alpha- and beta-adrenoceptors, G proteins, L-type voltage-dependent calcium channels, calcium influx, potassium channels, PhoA/Rho-kinase pathway, calcium sensitization, 14, and 612
- Language:
- English
- Description:
- b1_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 th e 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., b2_ there is considerable information on th e complex neural and vascular alterations in rats with established hypertension, the detailed description of their appearance during the induction of hypertension is still missing., M. Pintérová, J. Kuneš, J. Zicha., and Obsahuje bibliografii a bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3027. Altered pulmonary vasoreactivity in the chronically hypoxic lung
- Creator:
- Shimoda, L. A., Sham, J. S. K., and Sylvester, J. T.
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, oxid dusnatý, plicní hypertenze, nitric oxide, pulmonary hypertension, contraction, endothelin-1, angiotensin II, membrane potential, 14, and 612
- Language:
- English
- Description:
- Prolonged exposure to alveolar hypoxia induces physiological changes in the pulmonary vasculature that result in the development of pulmonary hypertension. A hallmark of hypoxic pulmonary hypertension is an increase in vasomotor tone. In vivo, pulmonary arterial smooth muscle cell contraction is influenced by vasoconstrictor and vasodilator factors secreted from the endothelium, lung parenchyma and in the circulation. During chronic hypoxia, production of vasoconstrictors such as endothelin-1and angiotensin II is enhanced locally in the lung, while synthesis of vasodilators may be reduced. Altered reactivity to these vasoactive agonists is another physiological consequence of chronic exposure to hypoxia. Enhanced contraction in response to endothelin-1 and angiotensin II, as well as depressed vasodilation in response to endothelium-derived vasodilators, has been documented in models of hypoxic pulmonary hypertension. Chronic hypoxia may also have direct effects on pulmonary vascular smooth muscle cells, modulating receptor population, ion channel activity or signal transduction pathways. Following prolonged hypoxic exposure, pulmonary vascular smooth muscle exhibits alterations in K+ current, membrane depolarization, elevation in resting cytosolic calcium and changes in signal transduction pathways. These changes in the electrophysiological parameters of pulmonary vascular smooth muscle cells are likely associated with an increase in basal tone. Thus, hypoxia-induced modifications in pulmonary arterial myocyte function, changes in synthesis of vasoactive factors and altered vasoresponsiveness to these agents may shift the environment in the lung to one of contraction instead of relaxation, resulting in increased pulmonary vascular resistance and elevated pulmonary arterial pressure., L. A. Shimoda, J. S. K. Sham, J. T. Sylvester., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3028. Alternative characterisations of Lorentz-Karamata spaces
- Creator:
- Edmunds;, David Eric and Opic, Bohumír
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Lorentz-Karamata spaces, equivalent quasi-norms, weighted norm inequalities, fractional maximal operators, and Riesz potentials
- Language:
- English
- Description:
- We present new formulae providing equivalent quasi-norms on Lorentz-Karamata spaces. Our results are based on properties of certain averaging operators on the cone of non-negative and non-increasing functions in convenient weighted Lebesgue spaces. We also illustrate connections between our results and mapping properties of such classical operators as the fractional maximal operator and the Riesz potential (and their variants) on the Lorentz-Karamata spaces.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
3029. Alternative culture in a socialist city: Punkers and long-haired people in Prague in the 1980s' /
- Creator:
- Pixová, Michaela
- Type:
- text and studie
- Subject:
- Sociologie kultury. Kulturní život, města, punk, kultura alternativní, totalita, společnost socialistická, represe komunistické, Československo 1969-1989, and mládež, studenti a jejich organizace
- Language:
- English
- Description:
- Alternativní kultura v socialistickém městě: Punkeři a máničky v Praze v 80. letech 20. století.
- Rights:
- unknown
3030. Alternative foods for the multicoloured Asian lady beetle Harmonia axyridis (Coleoptera: Coccinellidae)
- Creator:
- Berkvens, Nick, Landuyt, Carmen, Deforce, Koen, Berkvens, Dirk, Tirry, Luc, and de Clercq, Patrick
- Type:
- article, model:article, and TEXT
- Subject:
- Coccinellidae, Harmonia axyridis, invasive species, development, frugivory, fungivory, pollinivory, and reproduction
- Language:
- English
- Description:
- The multicoloured Asian lady beetle Harmonia axyridis (Coleoptera: Coccinellidae) may potentially exploit a range of "alternative" food sources. The nutritional value of three common non-prey food groups, i.e. fruit, fungi and pollen, is examined in this study. Development, reproduction and survival of the species were assessed in the laboratory on diets of apple, pear and raspberries and the fungi Oidium lycopersicum, Botrytis cinerea, Sclerotinia sclerotiorum and Rhizoctonia solani. When fed exclusively on these foods this ladybird failed to complete its development or reproduce. However, larval and adult survival was prolonged by 4 to 8 days and 55 to 67 days, respectively, when fruit was offered compared with only water. During a field study H. axyridis adults were collected monthly from March to October at two locations near Ghent, Belgium. Gut analysis demonstrated that, despite the continued presence of aphids, over 90% of all the adults collected contained pollen throughout the year. The pollen belonged to 53 different pollen types. Monthly average numbers of pollen grains in the gut varied from 5 to 233 grains. In contrast, there were about 35,000 grains in the guts of H. axyridis females that successfully developed and reproduced in the laboratory on diet that consisted of only pollen. This suggests that in the field in the majority of cases pollinivory mainly only provided complementary nutrients for this coccinellid. The use of alternative non-prey foods like pollen and fruit may play a role in sustaining populations of this coccinellid at times when the optimal prey is absent.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public