http://models.cellml.org/w/hnielsen/gall_2000 en-us Cytosolic calcium plays a crucial role as a second messenger in cellular signalling. Various cell types, including hepatocytes, display Ca2+ oscillations when stimulated by an extracellular signal. However, the biological relevance of this temporal organization remains unclear. In this paper, we investigate theoretically the e!ect of Ca2+ oscillations on a particular example of cell regulation: the phosphorylation/dephosphorylation cycle controlling the activation of glycogen phosphorylase in hepatocytes. By modelling periodic sinusoidal variations in the intracellular Ca2+ concentration, we show that Ca2+ oscillations reduce the threshold for the activation of the enzyme. Furthermore, as the activation of a given enzyme depends on the kinetics of its phosphorylation/dephosphorylation cycle, speciality can be encoded by the oscillation frequency. Finally, using a model for signal-induced Ca2+ oscillations based on Ca2+-induced Ca2+ release, we show that realistic Ca2+ oscillations can potentiate the response to a hormonal stimulation. These results indicate that Ca2+ oscillations in hepatocytes could contribute to increase the efficiency and speciality of cellular signalling, as shown experimentally for gene expression in lymphocytes (Dolmetsch et al., 1998). http://models.cellml.org/w/hnielsen/gall_2000/@@file/fbd835be20e34bd948fa541c37b3d58d2bd3aa05 Removed error in html Hanne Nielsen <hnie010@aucklanduni.ac.nz> 2011-11-11 13:25 +1300 http://models.cellml.org/w/hnielsen/gall_2000/@@file/7039a8d600dfd3fe770adbb4e877bb92eecfde53 Fixed link in html file Hanne Nielsen <hnie010@aucklanduni.ac.nz> 2011-11-11 13:04 +1300 http://models.cellml.org/w/hnielsen/gall_2000/@@file/3cfed6c7c5e9f5aa8bc43c9244f7b4291d4b08f7 Added metadata to cellML files Hanne Nielsen <hnie010@aucklanduni.ac.nz> 2011-11-11 13:04 +1300 http://models.cellml.org/w/hnielsen/gall_2000/@@file/943cdd037f59fd7e0ffa0be0e544f1343d403425 Added tagged images in ai svg and png format. Both models now have cliackable SVG sessions Hanne Nielsen <hnie010@aucklanduni.ac.nz> 2011-09-12 15:08 +1200 http://models.cellml.org/w/hnielsen/gall_2000/@@file/b79d84b900dfc3389a028b01a25efe0b8049a21f Added HTML file, xul and clickable session for the first cellML model. Traces still to be matched and added for second sesison file with both Pha and Z Hanne Nielsen <hnie010@aucklanduni.ac.nz> 2011-08-23 10:59 +1200 http://models.cellml.org/w/hnielsen/gall_2000/@@file/c05f1aa1bb6b3367275062552f5797d8b7ff689d Removed previous CellML files from workspace Hanne Nielsen <hnie010@aucklanduni.ac.nz> 2011-08-18 14:19 +1200 http://models.cellml.org/w/hnielsen/gall_2000/@@file/757a09639fcf4277510d6a56a7a09e758d68a77f Added new cellML files for a and b. a now reproduces results but b oscillates differently. Added session files without SVG image. To be added. Hanne Nielsen <hnie010@aucklanduni.ac.nz> 2011-08-18 14:16 +1200 http://models.cellml.org/w/hnielsen/gall_2000/@@file/4b072cdab55150d9b132212ac891e33c1ed58801 Added cellML files again after looking at equations. Still do not reproduce published results Hanne Nielsen <hnie010@aucklanduni.ac.nz> 2011-08-16 11:03 +1200 http://models.cellml.org/w/hnielsen/gall_2000/@@file/b06f1ceb829bc7be90d0c11b5863266752fb89c6 Added images in ai svg and png format. CellML files based on equations 1-3 (a) and 4-8 (b). HTML file also added. Does not reproduce published figure ut does run in OpenCell. Hanne Nielsen <hnie010@aucklanduni.ac.nz> 2011-08-08 16:02 +1200 http://models.cellml.org/w/hnielsen/gall_2000/@@file/5cb55f954586da37e83d3cb535aa444b4303f7a6 Added images and HTML file to workspace Hanne Nielsen <hnie010@aucklanduni.ac.nz> 2011-08-08 14:45 +1200