![Figure 4. Simulation of calcium sparks with different parameters of the RyR and CRU models not related to the RyR activation site. (A) Typical simulations for cytosolic [Ca2+] of 0.05 (top row) and 0.4 µM (bottom row) for (left to right) a threefold decrease of KO00, a threefold increase of KI, and a threefold decrease of trp. (B–G) The calcium dependence of the frequency of triggered sparks (ΔϕSpark; B), the increase of the average number of open RyRs in triggered sparks (Δn−O; C), spontaneous spark frequency (ϕSpark; D), calcium sensitivity of spontaneous spark frequency (∂CaϕSpark; E), average number of open RyRs in spontaneous sparks (n−O; F), and calcium sensitivity of the average number of open RyRs in spontaneous sparks (∂Can−O; G) for control conditions (black symbols) and for decreased (red symbols) and increased (blue symbols) parameters KO00, KI, and trp. The parameters were changed to 33 and 300% of control. Theoretical predictions (D–G) and predictions of multiple linear regression (B and C) are shown by solid lines. Theoretical values and data from simulations at calcium concentrations used in the experiment (Lukyanenko and Gyorke, 1999) shown in Fig. 1 are shown as open and closed symbols, respectively. Error bars represent mean ± SEM.](https://cdn.rupress.org/rup/content_public/journal/jgp/145/6/10.1085_jgp.201411281/5/jgp_201411281_fig4.jpeg?Expires=1767758749&Signature=yMcmZt5GTESa-h8S5zv8x4XqKM4UVks--tsPYk3iDPsg0GMKOoQC31tXWCETZak~aUT05a~xV1dNAinsm4jz-Te8FbuNbSA~3EN7aUD9caVANje4cGxJM~YQGozMwio7kdCRV4Gz5J4pfNqYt-k467FiAyu~fzByGE72MtS9XW352OHdH8YVfbYcPFAKP6sGDGCC3NEMnTO9paAfRiPdcisYeyYw6em0trQGWwYeFdpykXMu1JyrDeNlaDPHJZHVhxvGFhPt7hptd03u~HrYs4Qicdk1rRqvo2eaebZ28jVjDBHqOPEJOsQuDBxEqrWsaIPoAaGuG-7wsPEvYovmKA__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
Simulation of calcium sparks with different parameters of the RyR and CRU models not related to the RyR activation site. (A) Typical simulations for cytosolic [Ca2+] of 0.05 (top row) and 0.4 µM (bottom row) for (left to right) a threefold decrease of KO00, a threefold increase of KI, and a threefold decrease of trp. (B–G) The calcium dependence of the frequency of triggered sparks (ΔϕSpark; B), the increase of the average number of open RyRs in triggered sparks C), spontaneous spark frequency (ϕSpark; D), calcium sensitivity of spontaneous spark frequency (∂CaϕSpark; E), average number of open RyRs in spontaneous sparks F), and calcium sensitivity of the average number of open RyRs in spontaneous sparks G) for control conditions (black symbols) and for decreased (red symbols) and increased (blue symbols) parameters KO00, KI, and trp. The parameters were changed to 33 and 300% of control. Theoretical predictions (D–G) and predictions of multiple linear regression (B and C) are shown by solid lines. Theoretical values and data from simulations at calcium concentrations used in the experiment (Lukyanenko and Gyorke, 1999) shown in Fig. 1 are shown as open and closed symbols, respectively. Error bars represent mean ± SEM.
