%0 Journal Article %1 Mich_2001_614 %A Michailova, A. %A McCulloch, A. %D 2001 %J Biophys J %K Adenosine Biological; Buffers; Calcium, Cells, Conductivity; Cultured; Diphosphate, Electric Ion Kinetics; Magnesium, Models, Myocardium, Patch-Clamp Potassium, Pumps, Sodium, Techniques; Transport; Triphosphate, cytology/metabolism; metabolism metabolism; %N 2 %P 614--629 %R 10.1016/S0006-3495(01)75727-X %T Model study of ATP and ADP buffering, transport of Ca(2+) and Mg(2+), and regulation of ion pumps in ventricular myocyte. %U http://dx.doi.org/10.1016/S0006-3495(01)75727-X %V 81 %X We extended the model of the ventricular myocyte by Winslow et al. (Circ. Res 1999, 84:571-586) by incorporating equations for Ca(2+) and Mg(2+) buffering and transport by ATP and ADP and equations for MgATP regulation of ion transporters (Na(+)-K(+) pump, sarcolemmal and sarcoplasmic Ca(2+) pumps). The results indicate that, under normal conditions, Ca(2+) binding by low-affinity ATP and diffusion of CaATP may affect the amplitude and time course of intracellular Ca(2+) signals. The model also suggests that a fall in ATP/ADP ratio significantly reduces sarcoplasmic Ca(2+) content, increases diastolic Ca(2+), lowers systolic Ca(2+), increases Ca(2+) influx through L-type channels, and decreases the efficiency of the Na(+)/Ca(2+) exchanger in extruding Ca(2+) during periodic voltage-clamp stimulation. The analysis suggests that the most important reason for these changes during metabolic inhibition is the down-regulation of the sarcoplasmic Ca(2+)-ATPase pump by reduced diastolic MgATP levels. High Ca(2+) concentrations developed near the membrane might have a greater influence on Mg(2+), ATP, and ADP concentrations than that of the lower Ca(2+) concentrations in the bulk myoplasm. The model predictions are in general agreement with experimental observations measured under normal and pathological conditions.

@article{Mich_2001_614, abstract = {We extended the model of the ventricular myocyte by Winslow et al. (Circ. Res 1999, 84:571-586) by incorporating equations for Ca(2+) and Mg(2+) buffering and transport by ATP and ADP and equations for MgATP regulation of ion transporters (Na(+)-K(+) pump, sarcolemmal and sarcoplasmic Ca(2+) pumps). The results indicate that, under normal conditions, Ca(2+) binding by low-affinity ATP and diffusion of CaATP may affect the amplitude and time course of intracellular Ca(2+) signals. The model also suggests that a fall in ATP/ADP ratio significantly reduces sarcoplasmic Ca(2+) content, increases diastolic Ca(2+), lowers systolic Ca(2+), increases Ca(2+) influx through L-type channels, and decreases the efficiency of the Na(+)/Ca(2+) exchanger in extruding Ca(2+) during periodic voltage-clamp stimulation. The analysis suggests that the most important reason for these changes during metabolic inhibition is the down-regulation of the sarcoplasmic Ca(2+)-ATPase pump by reduced diastolic MgATP levels. High Ca(2+) concentrations developed near the membrane might have a greater influence on Mg(2+), ATP, and ADP concentrations than that of the lower Ca(2+) concentrations in the bulk myoplasm. The model predictions are in general agreement with experimental observations measured under normal and pathological conditions.}, added-at = {2009-06-03T11:20:58.000+0200}, author = {Michailova, A. and McCulloch, A.}, biburl = {https://www.bibsonomy.org/bibtex/2af2a37f19548887bce7c6d6568e78f5d/hake}, description = {The whole bibliography file I use.}, doi = {10.1016/S0006-3495(01)75727-X}, institution = {U CA San Diego, La Jolla}, interhash = {9c9c6205057e0e049a005aafb45f3a2a}, intrahash = {af2a37f19548887bce7c6d6568e78f5d}, journal = {Biophys J}, keywords = {Adenosine Biological; Buffers; Calcium, Cells, Conductivity; Cultured; Diphosphate, Electric Ion Kinetics; Magnesium, Models, Myocardium, Patch-Clamp Potassium, Pumps, Sodium, Techniques; Transport; Triphosphate, cytology/metabolism; metabolism metabolism;}, month = Aug, number = 2, pages = {614--629}, pii = {S0006-3495(01)75727-X}, pmid = {11463611}, timestamp = {2009-06-03T11:21:23.000+0200}, title = {Model study of ATP and ADP buffering, transport of Ca(2+) and Mg(2+), and regulation of ion pumps in ventricular myocyte.}, url = {http://dx.doi.org/10.1016/S0006-3495(01)75727-X}, volume = 81, year = 2001 }