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1
Content available remote

Changes in intracellular calcium concentration influence beat-to-beat variability of action potential duration in canine ventricular myocytes

100%
Kistamas K., Szentandrassy, Hegyi B., Vaczi K., Ruzsnavszki F., Horvath B., Banyasz T., Nanasi P. P., Magyar J.
Journal of Physiology and Pharmacology
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2015
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tom 66
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nr 1
2

Asynchronic and independent secretion of elastic fiber components

100%
Hinek A., Czarnowska E., Barcew B., Kawiak J.
Folia Histochemica et Cytobiologica
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1984
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tom 22
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nr 2
3

Role of immunohistochemical and histochemical profiling in H and E-based diagnosis of scrotal leiomyosarcoma of dartos muscle

100%
Wincewicz A., Lewitowicz P., Sulkowska U., Sulkowski S., Horecka-Lewitowicz A., Koziel D., Gluszek S.
Folia Histochemica et Cytobiologica
|
2013
|
tom 51
|
nr 4
4
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Content available

Myocytes isolated from porcine coronary arteries: reduction of currents through L-type Ca-channels by verapamil-type Ca-antagonists

100%
Klockner U., Isenberg G.
Journal of Physiology and Pharmacology
|
1991
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tom 42
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nr 2
Myocytes were enzymatically isolated from large epicardial arteries of the pig. In the cell attached configuration, we studied currents through L-type Ca-channels. At 22°C, open channel conductance was 9 pS with 110 mM Ba²⁺ and 24 pS with 110 mM Ba²⁺ as charge carrier. According to the life time of the open state, 2 ’modes’ of gating are distinguished; mode 1 contributed time constants shorter than 1 ms, mode 2 those longer than 6 ms to the open time distribution. Mode 2 openings appeared spontaneously, more frequently with Ba²⁺ than with Ca²⁺ as charge carrier. The Ca-agonist Bay K 8644 (0.5 pM) facilitated the appearance of mode 2. Bath application of the phenylalkylamine D600 (1 µM) did not change the gating modes, but it reduced the channel openness by increasing the percentage of blank records. With whole cell recordings, we studied reduction of Ica by 1 µM D 600 at 3.6 mM [Ca²⁺] and 35°C. At a holding potential of -45 mV, D600 induced an ’initial block’ of 35% (10% at -65 mV). Upon repetitive 1 Hz pulsing (170 ms to 0 mV) an additional, ’use-dependent’ block developed with time. More negative holding potentials attenuated reduction of Ica by D600, hyperpolarizations to -100 mV had an ’unblocking’ effect. In regard to reduction of Ica, we compared the partially uncharged D 600 (membrane permeable) with the completely charged compound D890 (membrane impermeable). When applied with the bath, 1 or 10 pM D 600 reduced Ica dose-dependently whereas D 890 was ineffective. When D890 was applied via the patch electrode to the cytosol, it reduced Ica. We discuss that D 600 enters the cell in the uncharged lipid soluble form and reaches form the inside its receptor associated with the Ca-channel.
5
Content available remote

Voltage dependent activation of tonic contraction in cardiac myocytes

100%
Mackiewicz U., Emanuel K., Lewartowski B.
Journal of Physiology and Pharmacology
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2003
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tom 54
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nr 3
Contractions of isolated single myocytes of guinea pig heart stimulated by rectangular depolarizing pulses consist of a phasic component and a voltage dependent tonic component. In this study we analyzed the mechanism of activation of the graded, sustained contractions elicited by slow ramp depolarization and their relation to the components of contractions elicited by rectangular depolarizing pulses. Experiments were performed at 37°C in ventricular myocytes of guinea pig heart. Voltage-clamped myocytes were stimulated by the pulses from the holding potential of -40 to +5 mV or by ramp depolarization shifting voltage within this range within 6 s. [Ca2+]i was monitored as fluorescence of Indo 1-AM and contractions were recorded with the TV edge-tracking system. Myocytes responded to the ramp depolarization between -25 and -6 mV by the slow, sustained increase in [Ca2+]i and shortening, the maximal amplitude of which was in each cell similar to that of the tonic component of Ca2+ transient and contraction. The contractile responses to ramp depolarization were blocked by 200 µM ryanodine and Ca2+-free solution, but were not blocked by 20 µM nifedipine or 100 - 200 µM Cd2+ and potentiated by 5 mM Ni2+. The responses to ramp depolarization were with this respect similar to the tonic but not to the phasic component of contraction: both components were blocked by 200 µM ryanodine, and were not blocked by Cd2+ or Ni2+ despite complete inhibition of the phasic Ca2+ current. However, the phasic component but not the tonic component of contraction in cells superfused with Ni2+ was inhibited by nifedipine. Both components of contraction were inhibited by Ca2+-free solution superfused 15 s prior to stimulation. Conclusions: In myocytes of guinea pig heart the contractile response to ramp depolarization is equivalent to the tonic component of contraction. It is activated by Ca2+ released from the sarcoplasmic reticulum by the ryanodine receptors. Their activation and inactivation is voltage dependent and it does not depend on the Ca2+ influx by the Ca2+ channels or reverse mode Na+/Ca2+ exchange, however, it may depend on Ca2+ influx by some other, not yet defined route.
6

Arterial angioplasty. Thrombosis and restenosis

100%
Badimon L., Chesebro J. H., Badimon J. J., Fuster V.
Journal of Physiology and Pharmacology. Supplement
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1993
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tom 44
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nr 2
7
Content available remote

Protecting the cellular energy state during contractions: role of AMP deaminase

84%
Hancock C. R., Brault J. J., Terjung R. L.
Journal of Physiology and Pharmacology. Supplement
|
2006
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tom 57
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nr 10
17-29
AMP deaminase activity (AMPIMP+NH3) is the entry reaction to the purine nucleotide cycle. In skeletal muscle, excessive energy demands during contractions leads to a net production of ADP, because ATP hydrolysis exceeds ADP rephosphorylation. Elevations in ADP increase AMP, via the myokinase reaction. This accumulation of ATP hydrolysis products should lead to a catastrophic reduction in the energy state of the myocyte. The removal of AMP to IMP in times of excessively high energy demands have been hypothesized as essential to protect the energy state of the cell. While AMP deamination leads to a net loss of adenine nucleotides (principally, as ATP), the viability of the myocyte is preserved. Following these demanding contraction conditions, the concentration of IMP of fast-twitch muscle is rapidly reduced, typically with the return of the muscle adenine nucleotide content (ATP + ADP + AMP) to pre-contraction levels. While these observations are generally observed for fast-twitch skeletal muscle and consistent with the hypothesis, there has been no direct experimental evaluation. In the AK1-/- mouse, there is a markedly reduced accumulation of AMP, during conditions of excessive contractile activity. Rather, there is a high ADP concentration, approaching 1.5 mM, that remains unbound 'free' within the muscle. This contributes to an inordinate reduction in the ATP/ADP ratio. At the same time, PCr hydrolysis is nearly complete leading to a large increase in orthophosphate. In combination, this leads to an exceptional decline in the free energy of ATP hydrolysis. This is projected to impair Ca2+ handling by the sarcoplasmic reticulum and slow cross-bridge cycling rate. The outcome should be slowed contraction characteristics and possible contracture. While some contractile changes were observed, there was a remarkable ability of the muscle to function under these challenging energetic conditions. Thus, it is not essential that the AMP deaminase reaction be operating during intense contraction conditions. This helps explain why patients deficient in AMP deaminase do not always exhibit an impaired muscle function.
8
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The effect of menadione on sarcoplasmic reticulum Ca2plus and contractions of single guinea-pig cardiomyocytes

84%
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

Detection of cyclic nucleotide phosphodiesterase mRNA in mouse skeletal muscle tissue and primary cultured myocytes

84%
Gu J. N., Chen W., Yu T. Q., Lu P., Mu X., Xu J. Q.
Journal of Animal and Feed Sciences
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2007
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tom 16
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nr 4
696-705
10
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

84%
Mackiewicz U., Lewartowski B.
Journal of Physiology and Pharmacology
|
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.
11
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Content available

Properties of ventricular myocytes isolated from the hypertrophied and failing hearts of spontaneously hypertensive rats

84%
Emanuel K., Mackiewicz U., Pytkowski B., Lewartowski B.
Journal of Physiology and Pharmacology
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1999
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tom 50
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nr 2
12
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

84%
Lewartowski B., Wolska B.
Journal of Physiology and Pharmacology
|
1993
|
tom 44
|
nr 3
13
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

84%
Mackiewicz U., Emanuel K., Lewartowski B.
Journal of Physiology and Pharmacology
|
2001
|
tom 52
|
nr 3
14

Requirements for the localization of p130 Cas to Z-lines in cardiac myocytes

84%
Kovacic-Milivojevic B., Damsky C. C., Gardner D. G., Ilic D.
Cellular and Molecular Biology Letters
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2002
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tom 07
|
nr 2
The vertebrate heart responds to hemodynamic load with the enlargement of postmitotic, terminally differentiated cardiac myocytes. Such hypertrophic changes are characterized by alterations in sarcomeric organization and gene expression. Previously, we established a role for a nonreceptor tyrosine kinase, focal adhesion kinase, in signaling the changes in cytoskeletal organization associated with hypertrophy [1], Here, we report on data supporting a key role for p130Cas in this process. In neonatal cardiac myocytes FAK, Cas and paxillin are located in sarcomeric Z-lines, suggesting that the Z-line is an important signaling locus in these cells. The expression of different Cas mutants results in a nearly complete loss of sarcomeric organization in these myocytes. Moreover, expression of the C-terminal focal adhesion-targeting domain of FAK both disrupted sarcomeric organization and interfered with the localization of endogenous Cas to Z-lines. These findings suggest that the association of FAK and Cas and the preservation of multiple protein-interaction motifs of Cas are required for the correct assembly of sarcomeres in cardiac myocytes.
15

Cloning and expression of a new inositol 1,4,5-trisphosphate receptor type 1 splice variant in adult rat atrial myocytes

67%
Subedi K. P., Singh T. D., Kim J.-C., Woo S.-H.
Cellular and Molecular Biology Letters
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2012
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tom 17
|
nr 1
Inositol 1,4,5-trisphosphate receptor type 1 (IP3R1) is already known to be highly expressed in the brain, and is found in many other tissues, including the atrium of the heart. Although the complete primary structure of IP3R1 in the rat brain has been reported, the complete sequence of an IP3R1 clone from atrial myocytes has not been reported. We isolated an IP3R1 complementary DNA (cDNA) clone from isolated adult rat atrial myocytes, and found a new splice variant of IP3R1 that was different from a previously reported IP3R1 cDNA clone obtained from a rat brain (NCBI GenBank accession number: NM_001007235). Our clone had 99% similarity with the rat brain IP3R1 sequence; the exceptions were 39 amino acid deletions at the position of 1693–1731, and the deletion of phenylalanine at position 1372 that lay in the regulatory region. Compared with the rat brain IP3R1, in our clone proline was replaced with serine at residue 2439, and alanine was substituted for valine at residue 2445. These changes lie adjacent to or within the fifth transmembrane domain (2440–2462). Although such changes in the amino acid sequences were different from the rat brain IP3R1 clone, they were conserved in human or mouse IP3R1. We produced a plasmid construct expressing the atrial IP3R1 together with green fluorescent protein (GFP), and successfully overexpressed the atrial IP3R1 in the adult atrial cell line HL-1. Further investigation is needed on the physiological significance of the new splice variant in atrial cell function.
16

Mesenchymal stem cells: characteristics and clinical applications

67%
Bobis S., Jarocha D., Majka M.
Folia Histochemica et Cytobiologica
|
2006
|
tom 44
|
nr 4
17
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

Effects of mibefradil, a blocker of T-type Ca2plus channels, in single myocytes and intact muscle of guinea-pig heart

67%
Emanuel K., Mackiewicz U., Pytkowski B., Lewartowski B.
Journal of Physiology and Pharmacology
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1998
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tom 49
|
nr 4
18
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

Effect of Na current on excitation-contraction coupling in ventricular myocytes of guinea pig heart

67%
Janiak R., Lewartowski B.
Journal of Physiology and Pharmacology
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1997
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tom 48
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nr 2
19

Effect of estradiol and progesterone on growth of porcine myometrial smooth muscle cells and phospholipase C and adenylate cyclase signalling systems in vitro

67%
Kisielewska J., Zezula-Szpyra A., Bilinska B., Flint A. P. F., Ziecik A. J.
Folia Histochemica et Cytobiologica
|
1997
|
tom 35
|
nr 3
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