Laasmaa M, Karro N, Birkedal R, Vendelin M.
PeerJ. 2019 Mar 29;7:e6652
PMID: 30956900
Full text: https://doi.org/10.7717/peerj.6652
Abstract
Analysis of calcium
sparks in cardiomyocytes can provide valuable information about
functional changes of calcium handling in health and disease. As a part
of the calcium sparks analysis, sparks detection and characterization is
necessary. Here, we describe a new open-source platform for automatic
calcium sparks detection from line ...
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Papers
Revealing calcium fluxes by analyzing inhibition dynamics in action potential clamp
Laasmaa M, Birkedal R, Vendelin M
J. Mol. Cell. Cardiol. Volume 100, November 2016, Pages 93–108
PMID: 27702573
Full text: http://doi.org/10.1016/j.yjmcc.2016.08.015
Abstract
In cardiac excitation-contraction coupling (ECC), calcium enters the cytosol via L-type Ca2+ channels (LTCC) and reverse Na+/Ca2+-exchange (NCXrev), or is released from the sarcoplasmic reticulum (SR) by Ca2+-induced Ca2+-release (CICR). The magnitude of Ca2+ influx via the different pathways varies with the ...
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Metabolic compartmentation in rainbow trout cardiomyocytes: coupling of hexokinase but not creatine kinase to mitochondrial respiration
Karro N, Sepp M, Jugai S, Laasmaa M, Vendelin M, Birkedal R
J. Comp. Physiol. B, Biochem. Syst. Environ. Physiol. 2016 Aug;
PMID: 27522222
Full text: http://doi.org/10.1007/s00360-016-1025-x
Abstract
Rainbow trout (Oncorhynchus mykiss) cardiomyocytes have a simple morphology with fewer membrane structures such as sarcoplasmic reticulum and t-tubules penetrating the cytosol. Despite this, intracellular ADP diffusion is restricted. Intriguingly, although diffusion is restricted, trout cardiom...
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Restricted ADP movement in cardiomyocytes: Cytosolic diffusion obstacles are complemented with a small number of open mitochondrial voltage-dependent anion channels
Simson P, Jepihhina N, Laasmaa M, Peterson P, Birkedal R, Vendelin M
J. Mol. Cell. Cardiol. Volume 97, August 2016, Pages 197–203;
PMID: 27261153
Full text: http://doi.org/10.1016/j.yjmcc.2016.04.012
Abstract
Adequate intracellular energy transfer is crucial for proper cardiac function. In energy starved failing hearts, partial restoration of energy transfer can rescue mechanical performance. There are two types of diffusion obstacles that interfere with energy transfer from mit...
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Cross-Bridge Group Ensembles Describing Cooperativity in Thermodynamically Consistent Way
Kalda M, Peterson P, Vendelin M
PLoS ONE 2015;10(9):e0137438
PMID: 26361396
Full text: http://doi.org/10.1371/journal.pone.0137438
Abstract
The aim of this work is to incorporate cooperativity into Huxley-type cross-bridge model in thermodynamically consistent way. While the Huxley-type models assume that cross-bridges act independently from each other, we take into account that each cross-bridge is influenced by its neighbors and cooperativity is induced by tropomyosin movement. For that...
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The location of energetic compartments affects energetic communication in cardiomyocytes
Birkedal R, Laasmaa M, Vendelin M
Front Physiol 2014;5:376
PMID: 25324784
Full text: http://dx.doi.org/10.3389/fphys.2014.00376
Abstract
The heart relies on accurate regulation of mitochondrial energy supply to match energy demand. The main regulators are Ca(2+) and feedback of ADP and Pi. Regulation via feedback has intrigued for decades. First, the heart exhibits a remarkable metabolic stability. Second, diffusion of ADP and other molecules is restricted specifically in heart an...
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Tight coupling of Na+/K+-ATPase with glycolysis demonstrated in permeabilized rat cardiomyocytes
Sepp M, Sokolova N, Jugai S, Mandel M, Peterson P, Vendelin M
PLoS ONE 2014;9(6):e99413
PMID: 24932585
Abstract
The effective integrated organization of processes in cardiac cells is achieved, in part, by the functional compartmentation of energy transfer processes. Earlier, using permeabilized cardiomyocytes, we demonstrated the existence of tight coupling between some of cardiomyocyte ATPases and glycolysis in rat. In this work, we studied contribution of two membrane ATPases and w...
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ADP protects cardiac mitochondria under severe oxidative stress
Sokolova N, Pan S, Provazza S, Beutner G, Vendelin M, Birkedal R, Sheu SS
PLoS ONE 2013;8(12):e83214
PMID: 24349464
Abstract
ADP is not only a key substrate for ATP generation, but also a potent inhibitor of mitochondrial permeability transition pore (mPTP). In this study, we assessed how oxidative stress affects the potency of ADP as an mPTP inhibitor and whether its reduction of reactive oxygen species (ROS) production might be involved. We determined quantitatively the effects of ...
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Unchanged mitochondrial organization and compartmentation of high-energy phosphates in creatine-deficient GAMT-/- mouse hearts
Branovets J, Sepp M, Kotlyarova S, Jepihhina N, Sokolova N, Aksentijevic D, Lygate CA, Neubauer S, Vendelin M, Birkedal R
Am. J. Physiol. Heart Circ. Physiol. 2013 Aug;305(4):H506-20
PMID: 23792673
Abstract
Disruption of the creatine kinase (CK) system in hearts of CK-deficient mice leads to changes in the ultrastructure and regulation of mitochondrial respiration. We expected to see similar changes in creatine-deficient mice, which lack the enzyme guanidinoacetate methyltr...
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Real-time determination of sarcomere length of a single cardiomyocyte during contraction
Peterson P, Kalda M, Vendelin M
Am. J. Physiol., Cell Physiol. 2013 Mar;304(6):C519-31
PMID: 23255581
Abstract
Sarcomere length of a cardiomyocyte is an important control parameter for physiology studies on a single cell level; for instance, its accurate determination in real time is essential for performing single cardiomyocyte contraction experiments. The aim of this work is to develop an efficient and accurate method for estimating a mean sarcomere length of a contracting cardiomy...
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