Fig 6. Homeostatic response of increasing SERCA uptake with normal and low RyR channel conductivity.
Panel (1): Dependence of pre-systolic values of free calcium concentrations in the SR and in the cytosol at steady state with maximum uptake of SERCA pump vup in the rabbit model. On the right, the relative increase of calcium during the calcium transient as a function of the maximum SERCA uptake νup. We take 100% to be the transient with the standard νup = 0.5 μM/ms. Panel (2): We present the same graphs as in the first panel but for a cell where the single channel conductivity of the RyR has been reduced. In this situation, the calcium transient is always lower than before and it does not improve as the uptake of SERCA is larger.