%0 Journal Article %1 Shan_2000_334 %A Shannon, T. R. %A Ginsburg, K. S. %A Bers, D. M. %D 2000 %J Biophys. J. %K 10620297 AMP-Dependent ATPase, Action Activation, Adenosine Adrenergic Allosteric Animals, Binding, Biological Biological, Caffeine, Calcium Calcium, Calcium-Binding Cardiac, Cardiovascular, Catalytic Cell Cells, Channels, Computer Congestive, Contraction, Cultured, Cyclic Cytosol, Diastole, Dogs, Domain, Electric Enzyme Exchanger, Factors, Failure, Ferrets, Fibers, Gov't, Heart Heart, Humans, Hydrolysis, Inhibitors, Intracellular Ion Isoproterenol, Kinases, Kinetics, Knockout, Membrane Membrane, Membranes, Mice, Microsomes, Models, Muscle Mutagenesis, Myocardial Myocardium, Myocytes, Nickel, Non-U.S. P.H.S., Patch-Clamp Phosphorylation, Potentials, Protein Proteins, Rabbits, Red, Regulation, Research Reticulum, Ruthenium Sarcoplasmic Signaling, Simulation, Sodium-Calcium Stimulation, Support, Techniques, Tetracaine, Thapsigargin, Thermodynamics, Time Transport, Triphosphate, U.S. Ventricles, beta-Agonists, {C}a$^{2+}$-Transporting %N 1 %P 334--343 %T Potentiation of fractional sarcoplasmic reticulum calcium release by total and free intra-sarcoplasmic reticulum calcium concentration. %U http://www.biophysj.org/cgi/content/full/78/1/334 %V 78 %X Our aim was to measure the influence of sarcoplasmic reticulum (SR) calcium content (Ca(SRT)) and free SR Ca (Ca(SR)) on the fraction of SR calcium released during voltage clamp steps in isolated rabbit ventricular myocytes. Ca(SRT), as measured by caffeine application, was progressively increased by conditioning pulses. Sodium was absent in both the intracellular and in the extracellular solutions to block sodium/calcium exchange. Total cytosolic calcium flux during the transient was inferred from I(Ca), Ca(SRT), Ca(i), and cellular buffering characteristics. Fluxes via the calcium current (I(Ca)), the SR calcium pump, and passive leak from the SR were evaluated to determine SR calcium release flux (J(rel)). Excitation-contraction (EC) coupling was characterized with respect to both gain (integral J(rel)/integral I(Ca)) and fractional SR calcium release. Both parameters were virtually zero for a small, but measurable Ca(SRT). Gain and fractional SR calcium release increased steeply and nonlinearly with both Ca(SRT) and Ca(SR). We conclude that potentiation of EC coupling can be correlated with both Ca(SRT) and Ca(SR). While fractional SR calcium release was not linearly dependent upon Ca(SR), intra-SR calcium may play a crucial role in regulating the SR calcium release process.

@article{Shan_2000_334, abstract = {Our aim was to measure the influence of sarcoplasmic reticulum (SR) calcium content ([Ca]({SRT})) and free SR [Ca] ([Ca](SR)) on the fraction of SR calcium released during voltage clamp steps in isolated rabbit ventricular myocytes. [Ca]({SRT}), as measured by caffeine application, was progressively increased by conditioning pulses. Sodium was absent in both the intracellular and in the extracellular solutions to block sodium/calcium exchange. Total cytosolic calcium flux during the transient was inferred from I(Ca), [Ca]({SRT}), [Ca](i), and cellular buffering characteristics. Fluxes via the calcium current (I(Ca)), the SR calcium pump, and passive leak from the SR were evaluated to determine SR calcium release flux (J(rel)). Excitation-contraction (EC) coupling was characterized with respect to both gain (integral J(rel)/integral I(Ca)) and fractional SR calcium release. Both parameters were virtually zero for a small, but measurable [Ca]({SRT}). Gain and fractional SR calcium release increased steeply and nonlinearly with both [Ca]({SRT}) and [Ca](SR). We conclude that potentiation of EC coupling can be correlated with both [Ca]({SRT}) and [Ca](SR). While fractional SR calcium release was not linearly dependent upon [Ca](SR), intra-SR calcium may play a crucial role in regulating the SR calcium release process.}, added-at = {2009-06-03T11:20:58.000+0200}, author = {Shannon, T. R. and Ginsburg, K. S. and Bers, D. M.}, biburl = {https://www.bibsonomy.org/bibtex/22d07c293fa17a0469f3ca9521e4d0f99/hake}, description = {The whole bibliography file I use.}, file = {Shan_2000_334.pdf:Shan_2000_334.pdf:PDF}, interhash = {bed090769960f0ac6df3fcf4aeefb0e1}, intrahash = {2d07c293fa17a0469f3ca9521e4d0f99}, journal = {Biophys. J.}, key = 102, keywords = {10620297 AMP-Dependent ATPase, Action Activation, Adenosine Adrenergic Allosteric Animals, Binding, Biological Biological, Caffeine, Calcium Calcium, Calcium-Binding Cardiac, Cardiovascular, Catalytic Cell Cells, Channels, Computer Congestive, Contraction, Cultured, Cyclic Cytosol, Diastole, Dogs, Domain, Electric Enzyme Exchanger, Factors, Failure, Ferrets, Fibers, Gov't, Heart Heart, Humans, Hydrolysis, Inhibitors, Intracellular Ion Isoproterenol, Kinases, Kinetics, Knockout, Membrane Membrane, Membranes, Mice, Microsomes, Models, Muscle Mutagenesis, Myocardial Myocardium, Myocytes, Nickel, Non-U.S. P.H.S., Patch-Clamp Phosphorylation, Potentials, Protein Proteins, Rabbits, Red, Regulation, Research Reticulum, Ruthenium Sarcoplasmic Signaling, Simulation, Sodium-Calcium Stimulation, Support, Techniques, Tetracaine, Thapsigargin, Thermodynamics, Time Transport, Triphosphate, U.S. Ventricles, beta-Agonists, {C}a$^{2+}$-Transporting}, month = Jan, number = 1, pages = {334--343}, pmid = {10620297}, timestamp = {2009-06-03T11:21:29.000+0200}, title = {Potentiation of fractional sarcoplasmic reticulum calcium release by total and free intra-sarcoplasmic reticulum calcium concentration.}, url = {http://www.biophysj.org/cgi/content/full/78/1/334}, volume = 78, year = 2000 }