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  • Ca2+ pump  (2)
  • Analytical Chemistry and Spectroscopy  (1)
  • Na+/Ca2+ exchange  (1)
  • cardiomyopathy  (1)
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Years
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Oxygen free radicals and calcium homeostasis in the heart (1994)
    Springer
    Molecular and cellular biochemistry 139 (1994), S. 91-100 
    Details
    ISSN: 1573-4919
    Keywords: sarcolemma ; myofibrils, Na+/Ca2+ exchange ; sarcoplasmic reticulum ; cardiac contraction ; Ca2+ pump
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Many experiments have been done to clarify the effects of oxygen free radicals on Ca2+ homeostasis in the hearts. A burst of oxygen free radicals occurs immediately after reperfusion, but we have to be reminded that the exact levels of oxygen free radicals in the hearts are yet unknown in both physiological and pathophysiological conditions. Therefore, we should give careful consideration to this point when we perform the experiments and analyze the results. It is, however, evident that Ca2+ overload occurs when the hearts are exposed to an excess amount of oxygen free radicals. Though ATP-independent Ca2+ binding is increased, Ca2+ influx through Ca2+ channel does not increase in the presence of oxygen free radicals. Another possible pathway through which Ca2+ can enter the myocytes is Na+−Ca2+ exchanger. Although, the activities of Na+−K+ ATPase and Na+−H+ exchange are inhibited by oxygen free radicals, it is not known whether intracellular Na+ level increases under oxidative stress or not. The question has to be solved for the understanding of the importance of Na+−Ca2+ exchange in Ca2+ influx process from extracellular space. Another question is ‘which way does Na+−Ca2+ exchange work under oxidative stress? Net influx or efflux of Ca2+?’ Membrane permeability for Ca2+ may be maintained in a relatively early phase of free radical injury. Since sarcolemmal Ca2+-pump ATPase activity is depressed by oxygen free radicals, Ca2+ extrusion from cytosol to extracellular space is considered to be reduced. It has also been shown that oxygen free radicals promote Ca2+ release from sarcoplasmic reticulum and inhibit Ca2+ sequestration to sarcoplasmic reticulum. Thus, these changes in Ca2+ handling systems could cause the Ca2+ overload due to oxygen free radicals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00944207
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Verapamil induced reduction of the myocardial β-adrenoceptor density in BIO 14.6 cardiomyopathic Syrian hamsters (1993)
    Springer
    Molecular and cellular biochemistry 121 (1993), S. 59-65 
    Details
    ISSN: 1573-4919
    Keywords: cardiomyopathy ; upregulation ; downregulation ; norepinephrine ; β-adrenoceptor density
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract In general, it is recognized that prolonged exposure to catecholamine leads to a reduction in the β-adrenoceptor density (downregulation). However, it has been previously reported that the myocardial β-adrenoceptor densities and norepinephrine levels significantly increase in the hearts of BIO 14.6 cardiomyopathic hamsters in the early stage. The mechanism of the increased β-adrenoceptor density is not clearly elucidated, and it can not be excluded that this phenomenon may be a secondary effect. The purpose of this study was to assess the effect of verapamil on the density of β-adrenoceptors in the heart of BIO 14.6 cardiomyopathic hamsters. The total number of β-adrenoceptors in untreated BIO 14.6 hamsters was significantly higher at 90 days of age (30.4±2.2 v.s. 25.9±1.4 fmol/mg protein, p〈0.05). BIO 14.6 hamsters received daily intraperitoneal injections of 5 mg/kg verapamil for 70 days, from an age of 20 days. Verapamil protected against progressive myocardial damage (total damage; 8.2±0.7 v.s. 0.4±0.2%/area, p〈0.05) and the myocardial β-adrenoceptor density returned to that of the normal control group (26.9±3.0 fmol/mg protein). Conversely, verapamil did not have an effect on the number of myocardial β-adrenoceptors in normal golden hamsters. This study showed that verapamil protected against progressive myocardial damage and myocardial β-adrenoceptor density returned to those of normal hamsters. These results suggest that an increased number of β-adrenoceptors in the early stage of BIO 14.6 cardiomyopathic hamsters may be involved in the secondary pathogenesis of cardiomyopathy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00928700
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Oxygen free radicals and calcium homeostasis in the heart (1994)
    Springer
    Molecular and cellular biochemistry 135 (1994), S. 99-108 
    Details
    ISSN: 1573-4919
    Keywords: sarcolemma ; myofibrils ; Na+/Ca2+ exchange ; sarcoplasmic reticulum ; cardiac contraction ; Ca2+ pump
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Many experiments have been done to clarify the effects of oxygen free radicals on Ca2+ homeostasis in the hearts. A burst of oxygen free radicals occurs immediately after reperfusion, but we have to be reminded that the exact levels of oxygen free radicals in the hearts are yet unknown in both physiological and pathophysiological conditions. Therefore, we should give careful consideration to this point when we perform the experiments and analayze the results. It is, however, evident that Ca2+ overload occurs when the hearts are exposed to an excess amount of oxygen free radicals. Though ATP-independent Ca2+ binding is increased, Ca2+ influx through Ca2+ channel does not increase in the presence of oxygen free radicals. Another possible pathway through which Ca2+ can enter the myocytes is Na+−Ca2+ exchanger. Although, the activities of Na+−K+ ATPase and Na+−Ca2+ exchanger. Although, the activities of Na+−H+ exchange are inhibited by oxygen free radicals, it is not known whether intracellular Na+ level increases under oxidative stress or not. The question has to be solved for the understanding of the importance of Na+−Ca2+ exchange in Ca2+ influx process from extracellular space. Another question is ‘which way does Na+−Ca2+ exchange work under oxidative stress? Net influx or efflux of Ca2+?’ Membrane permeability for Ca2+ may be maintained in a relatively early phase of free radical injury. Since sarcolemmal Ca2+-pump ATPase activity is depressed by oxygen free radicals, Ca2+ extrusion from cytosol to extracellular space is considered to be reduced. It has also been shown that oxygen free radicals promote Ca2+ release from sarcoplasmic reticulum and inhibit Ca2+ sequestration to sarcoplasmic reticulum. Thus, these changes in Ca2+ handling systems could cause the Ca2+ overload due to oxygen free radicals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00925965
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Conformational analysis of a synthetic carboxylic ionophore in solution by 1H NMR spectroscopyStudies on Synthetic Ionophores, V. For Part IV. see Ref. 1. (1986)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 24 (1986), S. 961-964 
    Details
    ISSN: 0749-1581
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 1H NMR spectra of the potassium salt of a synthetic polyether carboxylic ionophore, HO[CH2CH2O(1,2-C6H4)O]4CH2 (1,2-C6H4)COOH (1), in CDCl3 were assigned by two-dimensional NMR methods (2D chemical shift correlation and 2D NOE). The gauche conformer about the C - C bond of the 1,2-dioxyethylene groups of the potassium salt of 1 were found to be predominant from the analysis of the proton-proton vicinal coupling constants. Based on rotamer population analysis, together with nuclear Overhauser effect data, the preferred conformation of the potassium salt of 1 in the solution was estimated.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260241107
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
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