Figure 2

Effects of changes in the subcellular Na⁺ channel expression on action potential (AP) morphology and conduction velocity (CV). (A) AP propagation observed in the myocardial strand model with a spatially-homogeneous reduction in Na⁺ channel conductance in the lateral membrane (LM) of 100%g_Na,LM (a), 35%g_Na,LM (b), 7%g_Na,LM (c), and 0%g_Na,LM (d). (B) AP morphological changes (a), I_Na at the LM, I_Na,LM (b), I_to (c), I_CaL (d), I_NaK (e), I_Ks (f), I_Kr (g), and I_K1 (h) at the LM. (C) Schematic diagram of a intercellular junction part in the myocardial strand model (a), the post-junctional (I_m,post-JM) and pre-junctional transmembrane currents (I_m,pre-JM) (b), the transmembrane current (I_m,LM) and I_Na in the LM segments (c), the I_Na,JM of the pre-junctional membrane (pre-JM) in the 150th myocyte and of the post-junctional membrane (post-JM) in the 151st myocyte (d), the extracellular cleft potential (V_j) between the 150th and 151st myocytes (e), the intracellular potential (V_i) of the LM and pre-JM in 150th myocyte and of the post-JM in 151st myocyte (f), and the gap junctional current (I_g) between the 150th and 151st myocytes (g). The APs and ion currents were recorded in a myocyte located at the middle of the myocardial strand (cell #150). Each AP morphology corresponds to the waveforms in panel (A) indicated by red, cyan, blue, and green lines. CVs at 100%g_Na,LM, 35%g_Na,LM, 7%g_Na,LM and 0%g_Na,LM were 71.4, 53.6, 33.3, and 25.0 cm/s, respectively (see Table 1).