Effect of Ca²⁺ Efflux Pathway Distribution and Exogenous Ca²⁺ Buffers on Intracellular Ca²⁺ Dynamics in the Rat Ventricular Myocyte: A Simulation Study

Figure 5

Effect of EGTA (a) and BAPTA (b) on the amount of Ca²⁺ (𝑛_Ca) transferred through 𝐼_NaCa, 𝐼_pCa, 𝐽_up, and 𝐼_Ca, the peak value of Ca²⁺ transients in the t-tubular dyadic space ([Ca²⁺]_dt,peak) and in the cytosol ([Ca²⁺]_c,peak), the end-diastolic level of Ca²⁺ concentration in NSR ([Ca²⁺]_NSR,end), and APD₅₀ during a steady-state cycle at 1 Hz. All values are expressed as a percentage relative to those obtained in control conditions. Positive values of Δ𝑛_Ca related to 𝐼_NaCa, 𝐼_pCa, and 𝐽_up indicate an increase of Ca²⁺ extrusion while positive values related to 𝐼_Ca indicate increased Ca²⁺ entry. Buffer concentrations were 0.3, 1, 5, and 10 mM.

(a)

(b)