Fig. 4.
Voltage-dependence relationships of steady-state activation, inactivation, and decay. INa was measured from cells transiently expressing SCN5A, PMCA4b, and nNOS without SNTA1 (squares), with WT-SNTA1 (circles), A390V-SNTA1 (triangles), and A390V-SNTA1 plus the nNOS blocker l-NMMA (inverted triangles). (a) A390V-SNTA1 did not affect steady-state activation. (b) A390V-SNTA1 shifted steady-state inactivation by +6 mV. (c) The peak-current activation data from a are replotted as a conductance curve with inactivation relationships from b to show that A390V-SNTA1 increases the overlap of these relationships. Lines represent fits to Boltzmann equations with parameters of the fit and n numbers in Table 1.