Fig. 8.
Effects of S-LPS and ivabradine on pacemaker activity of a sinoatrial cell model.
A rabbit sinoatrial pacemaker cell model was used to investigate S-LPS-induced V1/2 shift of − 14 mV and ivabradine-induced If reduction (66% and 35% in control and S-LPS-treated cells, respectively). (A) I–V relationships of If using the computational model: If was voltage clamped from − 40 to − 140 mV in 10 mV steps of 3 s duration for indicated conditions (1) control, (2) ivabradine, (3) S-LPS, (4) S-LPS and ivabradine. (B) Time course of spontaneous action potentials computed for indicated conditions (1) to (4). (C) Changes in cycle length (CL) are represented as a function of (i) reduction in If conductance (If scaling factor) and (ii) If–V1/2 shift to more negative membrane potentials. The arrows indicate the specific parameter setting (1) to (4).