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1

A 2D-IR study of heat- and [13 C]urea-induced denaturation of sarcoplasmic reticulum Ca2plus -ATPase

100%
Iloro I., Goni F. M., Arrondo J. L. R.
Acta Biochimica Polonica
|
2005
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tom 52
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nr 2
Two-dimensional infrared correlation spectroscopy (2D-IR) was applied to the study of urea- and heat-induced unfolding denaturation of sarcoplasmic reticulum Ca2+-ATPase (SR ATPase). Urea at 2–3 M causes reversible loss of SR ATPase activity, while higher concentrations induce irreversible denaturation. Heat-induced denaturation is a non-two-state process, with an “intermediate state” (at t ≈ 45oC) characterized by the presence of protein monomers, instead of the native oligomers. 2D-IR reveals that urea denaturation causes loss of the structural transition to the “intermediate state”. Whenever the urea effect can be reversed, the transition to the “intermediate state” is re-established.
2
Content available remote

Temperature dependent contribution of Ca2+ transporters to relaxation in cardiac myocytes: important role of sarcolemmal Ca2+ -ATPase

100%
Mackiewicz U., Lewartowski B.
Journal of Physiology and Pharmacology
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2006
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tom 57
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nr 1
Activities of Ca2+-ATPase of sarcoplasmic reticulum (SERCA) and Na+/Ca2+ exchanger (NCX) involved in cellular Ca2+ turnover greatly change in hypertrophied and failing hearts. Unfortunately, contribution of these proteins as well as of the sarcolemmal Ca2+-ATPase (PMCA) to cellular Ca2+ turnover has been investigated almost exclusively at room temperature. PMCA is of particular interest since it may affect activity of calcineurin and nNOS. Therefore the objective of this study was to reinvestigate contribution of SERCA, NCX and PMCA to cell relaxation and the effect of PMCA on cell contraction at 37°C. Myocytes isolated from the ventricles of guinea pig and rat hearts and incubated with Indo-1 were field stimulated at the rate of 60/min. Contribution of SERCA, NCX and PMCA was calculated from the rate constants of the decaying components of electrically stimulated Ca2+ transients or of the transients initiated by caffeine dissolved in normal Tyrode or in 0Na, 0Ca Tyrode. Increase in temperature from 24 to 37°C increased the relative contribution of NCX from 6.1% to 7.5% in rat and from 21.3 to 51.9 % in guinea pig at the expense of SERCA. The contribution of the PMCA to relaxation in both species increased upon rise in temperature from 24 % to 37°C from negligible values to 3.7 %. In both species amplitude of Ca2+ transients was at 24°C nearly twice as high as at 37°C. It was nearly doubled by carboxyeosine (CE), a PMCA blocker at 37°C but was hardly affected at 24°C. The effects of CE were concentration-dependent and conformed with the degree of inhibition of activity of PMCA. Conclusions: PMCA plays an important role in regulation of myocardial contraction despite its small contribution to relaxation. In guinea pig but not in rat relative contribution of SERCA and NCX to relaxation is highly temperature dependent.
3

Thapsigargin: potent inhibitor of Ca2 transport ATP-ases of endoplasmic and sarcoplasmic reticulum

86%
Sabala P., Czarny M., Woronczak J. P., Baranska J.
Acta Biochimica Polonica
|
1993
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tom 40
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nr 3
4
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

Excitation-contraction coupling in cardiac muscle revisited

86%
Lewartowski B.
Journal of Physiology and Pharmacology
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2000
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tom 51
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nr 3
5
Content available remote

Effects of thapsigargin on stimulation frequency - dependent changes in mitochondrial calcium in rat cardiac myocytes

86%
Pytkowski B., Lewartowski B.
Journal of Physiology and Pharmacology
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2002
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tom 53
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nr 4,2
We investigated in the single myocytes of rat heart the effect of blocking of ATP-ase of sarcoplasmic reticulum (SR) on mitochondrial Ca2+ uptake and release. Mitochondrial Ca2+ content was investigated as Mn2+ - resistant fluorescence of Indo 1 - AM loaded into cells. SR ATP-ase was blocked with 10-6 M thapsigargin (Tg). Tg blocked almost completely stimulation Œdependent mitochondrial Ca2+ uptake and slowed down its release despite that the maximal cytosolic Ca2+ concentration was not decreased. We propose that mitochondrial stimulation -dependent Ca2+ uptake is greatly enhanced by [Ca2+ ] built by SR in microdomains adjacent to these organelle.
6
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The source of contracticle calcium in guinea-pig cardiac myocytes treated with thapsigargin

86%
Janiak R., Lewartowski B.
Journal of Physiology and Pharmacology
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1996
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tom 47
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nr 3
7

Cardiomyocyte marker expression in dogs with left atrial enlargement due to dilated cardiomyopathy or myxomatous mitral valve disease

72%
Janus I., Kandefer-Gola M., Ciaputa R., Noszczyk-Nowak A., Paslawska U., Tursi M., Nowak M.
Folia Histochemica et Cytobiologica
|
2017
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tom 55
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nr 2
8
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Content available

The effect of menadione on sarcoplasmic reticulum Ca2plus and contractions of single guinea-pig cardiomyocytes

72%
Lewartowski B., Zdanowski K., Wolska B. M.
Journal of Physiology and Pharmacology
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1991
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tom 42
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nr 2
We investigated the effect of 2-methyl-1,4-naphtoquinone (Menadione) on sarcoplasmic reticulum (SR) Ca2²⁺ content and electrically stimulated contractions (ESCs) of single isolated myocytes of guinea-pig ventricular myocardium. The contractures initiated by means of microinjections of caffeine into the close vicinity of the cell were used as an indirect index of the SR Ca²⁺ content. Superfusion of the cells for 45 min with Menadione resulted in gradual disappearance of contractile respones to caffeine, prolongation of time to peak amplitude of ESCs by 48±15% and complete inhibition of postrest and postextrasystolic potentiation. These results are consistent with those of Floreani and Caipenedo (7) who found that Menadione strongly inhibits the SR Ca²⁺ ATPase. Despite depletion of the SR Ca²⁺ the amplitude of ESCs did not change which suggests that contractions were initiated in the cells treated with Menadione by Ca²⁺ derived from the sources other than the SR.
9
Content available remote

Training induced decrease in oxygen cost of cycling is accompanied by down-regulation of SERCA expression in human vastus lateralis muscle

72%
Majerczak J., Karasinski J., Zoladz J. A.
Journal of Physiology and Pharmacology
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2008
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tom 59
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nr 3
589-602
We have examined the effect of 5 week cycling endurance training program on the sarco(endo)plasmic reticulum Ca2+ ATPase isoforms (SERCA1 and 2) and myosin heavy chain (MyHC) in the vastus lateralis muscle as well as on the oxygen uptake to power output ratio (VO2/PO) during incremental cycling. Fifteen untrained men performed an incremental cycling exercise until exhaustion before and after moderate intensity training. Muscle biopsies were taken from vastus lateralis before and after training program. Training resulted in higher (P = 0.048) maximal oxygen uptake (VO2max) as well as in higher power output reached at VO2max (P = 0.0001). Moreover, lower (P = 0.02) VO2/PO ratio determined during incremental moderate intensity cycling (i.e. 30-120 W) as well as lower (P = 0.003) VO2/PO ratio reached at VO2max were observed after the training. A significant down regulation of SERCA2 protein (P = 0.03) and tendency (P = 0.055) to lower SERCA1 content accompanied by lower (P<10-4) plasma thyroid hormone concentration, with no changes (P = 0.67) in MyHC composition in vastus lateralis muscle were found after training. We have concluded that the increase in mechanical efficiency of cycling occurring during first weeks of endurance training is not related to changes in MyHC composition but it may be due to down-regulation of SERCA pumps.
10

The network of calcium regulation in muscle

72%
Martonosi A. N., Pikula S.
Acta Biochimica Polonica
|
2003
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tom 50
|
nr 1
In this review the molecular characteristics and reaction mechanisms of different Ca2+ transport systems associated with various membranes in muscle cells will be summarized. The following topics will be discussed in detail: a brief history of early observations concerning maintenance and regulation of cellular Ca2+ homeostasis, characterization of the Ca2+ pumps residing in plasma membranes and sarco(endo)plasmic reticulum, mitochondrial Ca2+ transport, Ca2+ -binding proteins, coordinated expression of Ca2+ transport systems, a general background of muscle excitation-contraction coupling with emphasis to the calcium release channels of plasma membrane and sarcoplasmic reticulum, the structure and function of dihydropyridine and ryanodine receptors of skeletal and cardiac muscles, and finally their disposition in various types of muscles.
11
Content available remote

The effect of sarcoplasmic reticulum Ca2+ leak on contractile activity of guinea pig heart myocytes depends on activity of sarcoplasmic reticulum Ca2+-ATPase and Na+/Ca2+ exchanger

72%
Mackiewicz U., Lewartowski B.
Journal of Physiology and Pharmacology
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2008
|
tom 59
|
nr 2
Decreased expression of sarcoplasmic reticulum (SR) Ca2+-ATPase (SERCA), overexpression of Na+/Ca2+ exchanger (NCX) and diastolic SR Ca2+ leak from the ryanodine receptors (RyRs) are believed to contribute to the decrease of myocyte contraction in failing heart. In this work we induced Ca2+ leak through RyRs in isolated myocytes of guinea pig hearts by 20µM FK-506. The SR Ca2+ leak resulted in (1) decreased amplitude of cell shortening and of Ca2+ transients, (2) decreased rate of Ca2+ transients decay (3) enhanced diastolic Ca2+ loss. The effect of FK-506 on amplitude of cell shortening was reversed and that on diastolic Ca2+ loss blocked by partial inhibition of NCX due to lowering Na+ concentration in superfusion solution from 144 mM to 100 mM. The amplitude of cell shortening and Ca2+ transients decreased by FK-506 was significantly increased by 10-7 M thapsigargin. In conclusion, the effect of SR Ca2+ leak induced by FK-506 on myocyte contraction is strictly dependent on activity of SERCA and NCX.
12

Localization of glucose-6-phosphatase activity in the rat cardiac muscle by cobalt-based cytochemistry

72%
Zinchuk V. S.
Folia Histochemica et Cytobiologica
|
1993
|
tom 31
|
nr 4
13

Calcium uptake by sarcoplasmic reticulum in the presence of methylparathion

72%
Blasiak J.
Biophysics of Membrane Transport
|
1994
|
tom 12
|
nr 2
14
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

The effect of thapsigargin on sarcoplasmic reticulum Ca2 content and contractions of single myocytes of rat ventricular myocardium

72%
Lewartowski B., Wolska B.
Journal of Physiology and Pharmacology
|
1993
|
tom 44
|
nr 3
15

Animal electricity, Ca2plus and muscle contraction. A brief history of muscle research

72%
Martonosi A. N.
Acta Biochimica Polonica
|
2000
|
tom 47
|
nr 3
This brief review attempts to summarize some of the major phases of muscle research from Leeuwenhoek's description of sarcomeres in 1674, through Galvani's observation of animal electricity in 1791, to the discovery of Ca2+ as the key messenger in the coupling of nerve excitation to muscle contraction. The emerging molecular mechanism of the contraction process is one of the great achievements of biology, reflecting the intimate links between physics, chemistry and the life Sciences in the solution of biological problems.
16
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

Agonist of dihydropyridine receptors, BayK8644 depresses excitation-contraction coupling in myocytes of guinea pig heart

72%
Mackiewicz U., Emanuel K., Lewartowski B.
Journal of Physiology and Pharmacology
|
2001
|
tom 52
|
nr 3
17
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

Thapsigargin inhibits the effects of noradrenaline and high [Ca2]0 on kinetics but not on amplitude of contraction in the single myocytes of guinea pig heart

72%
Janiak R., Lewartowski B.
Journal of Physiology and Pharmacology
|
1995
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tom 46
|
nr 1
18

Calcium uptake by sarcoplasmic reticulum in the presence of the organophosphorus insecticide methylparathion

72%
Blasiak J.
Polish Journal of Environmental Studies
|
1995
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tom 04
|
nr 1
Using an isotope labelling technique it has been shown that an organophosphorus insecticide methylparathion (0,0-diethyl 0-4-nitrophenyl phosphorothioate) depressed calcium uptake by sarcoplasmic reticulum isolated from rabbit hind leg muscle. The effect was significant for insecticide concentrations of 50 and 100 µM and was dose-dependent The insecticide exerted a more pronounced effect on calcium uptake in the presence of ATP in the reticulum environment than in the absence of ATP. The inhibitory action of methylparathion on Ca2+ accumulation by sarcoplasmic reticulum can cause a rise in myoplasmic free Ca2+, the essential prerequisite for contracture activation. Because methylparathion, as well as other organophosphorus insecticides, is primarily neurotoxic, evidence of non-specific effect could be important for assessing its environmental safety.
19

The slow sarco-endoplasmic reticulum Ca2plus-ATPase declines independently of slow myosin in soleus muscle of diabetic rats

58%
Racz G., Szabo A., Ver A., Zador E.
Acta Biochimica Polonica
|
2009
|
tom 56
|
nr 3
487-493
 The sarcoplasmic reticulum Ca2+-ATPase (SERCA) isoforms are normally expressed in coordination with the corresponding myosin heavy chain (MyHC) isoforms in the fibers of skeletal muscle but this coordination is often disrupted in pathological conditions. In the streptozotocin-induced diabetes of rats (stz-rats), the soleus muscle showed peripheral neuropathy and the SERCA2a level decreased in type I (slow-oxidative) fibers compared to the control muscles, whereas the expression of the corresponding slow MyHC1 did not change. No difference was found at the mRNA and protein levels of SERCA and MyHC isoforms in the whole soleus, except that the level of the SERCA2a protein specifically declined in stz-rats compared to the controls. This shows that the coordinated expression of SERCA2a and MyHC1 is disrupted at the SERCA2a protein level in the diabetic soleus. The results are in line with previous observations that regulators of the Ca-homeostasis may adapt faster to type I diabetes than the contractile elements.
20

The structure of the Ca2plus -ATPase of sarcoplasmic reticulum

58%
Martonosi A. N., Pikula S.
Acta Biochimica Polonica
|
2003
|
tom 50
|
nr 2
In this article the morphology of sarcoplasmic reticulum, classification of Ca2+ -ATPase (SERCA) isoenzymes presented in this membrane system, as well as their topology will be reviewed. The focus is on the structure and interactions of Ca2+ -ATPase determined by electron and X-ray crystallog2r+aphy, lamellar X-ray and neutron diffraction analysis of the profile structure of Ca2+ -ATPase in sarcoplasmic reticulum multilayers. In addition, targeting of the Ca2+ -ATPase to the sarcoplasmic reticulum is discussed.
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