Figure 4.
Changes in the electrical activity of the Fabbri–Severi model cell at normal beating rate (normal autonomic tone) due to loss-of-function (reduced gNa and shifts in the steady-state activation and inactivation curves) and gain-of-function (Ipst) effects as observed for the 1795insD mutation in SCN5A. (A) Membrane potential (Vm). (B) Net membrane current (Inet). (C) Fast sodium current (INa). Effect of the loss-of-function effects per se (blue traces), the gain-of-function effects per se (red traces), and the combined effect (dashed green traces). In the model, INa is split into a wild-type and a mutant component, thus representing the effect of a heterozygous mutation.