Comparison of Simulated and Measured Calcium Sparks in Intact Skeletal Muscle Fibers of the Frog
This model is coded according to the description in the publication but is not able to reproduce the published results.
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The activation of Ca2+ sparks is an essential step in cardiac excitation-contraction coupling. A Ca2+ spark arises when sarcoplasmic reticulum (SR) Ca2+-release channels (ryanodine receptors, or RyRs) open, allowing Ca2+ to diffuse out of the intracellular store, down its electrochemical gradient into the cytoplasm. The increase in intracellular calcium concentration ([Ca2+]i) is recognised as a Ca2+ spark. After release, Ca2+ diffuses through the cytoplasm and binds to buffers such as troponin, ATP, parvalbumin and the SR Ca2+ pump.
In their 2002 paper, S.M. Baylor, S. Hollingworth and W.K. Chandler model Ca2+ sparks in frog intact skeletal muscle fibers. The model calculates changes in the concentration of free Ca2+ and of Ca2+ bound to the buffers and to the Ca2+ indicator fluo-3 (see the figure below).
The complete original paper reference is cited below:
Comparison of Simulated and Measured Calcium Sparks in Intact Skeletal Muscle Fibers of the Frog, S.M. Baylor, S. Hollingworth and W.K. Chandler, 2002, Journal of General Physiology , 120, 349-368. (Full text and PDF versions of the article are available to subscribers on the Journal of General Physiology website.) PubMed ID: 12198091
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|Schematic diagrams of the Ca2+ binding reactions for various buffers and indicators: A The reaction of Ca2+ with ATP in the presence of free Mg2+, B Reaction of Ca2+ with protein (Pr) and fluo-3 (Fluo), C Competitive reaction of Ca2+ and Mg2+ with parvalbumin (Parv), D Binding reaction of Ca2+ binding and transport by the sarcoplasmic reticulum Ca2+ pump (E), E One-step reaction of Ca2+ with Troponin (Trop), and F Two-step reaction of Ca2+ with Troponin (Trop).|