Figure 2.

FGF13 isoforms affect fast inactivation. (A,B) Currents were recorded from tsA201 cells transiently co-transfected with Nav1.5 and either pIRES-GFP or FGF13 isoforms (FGF13S, FGF13U and FGF13VY). Comparison normalized sample current traces recorded at −20 mV illustrating slowed inactivation of FGF13 isoforms co-expression groups as compared with control group. (C) Fast inactivation time constants were obtained by fitting the fast component of current decay with single exponential equation among each groups. Solid line are exponential fits to the mean time constants (Color stars indicate respective groups, *P < 0.05, compared to control). (D) Representative TTX-subtracted, whole-cell currents were recorded. Persistent current was measured in response to a 200-ms voltage step to −20 mV from a holding potential of −120 mV, and each trace was normalized to the peak sodium current. Insert (box) shows magnification of the persistent currents. Summarized data showed there were no different for persistent currents in each groups (insert).