Skip to main content
. 2009 Oct;76(4):861–871. doi: 10.1124/mol.109.055863

Fig. 7.

Fig. 7.

External QX-314 does not block the wild-type skeletal muscle Na+ channel or P segment mutants. A, Q399C (○) and F1236C (□) currents are elicited by depolarizing steps from −100 to −10 mV at a rate of 0.5 Hz, and 1 mM QX-314 is applied extracellularly. There is no effect on current amplitude, decay kinetics, or voltage-dependence. The I1575C (homologous to residue Ile1760 in the rat brain IIa channel) mutant in the domain IV-S6 membrane spanning repeat is blocked by ∼30% by extracellular QX-314. B, recovery of the wild-type (○, ●) and F1236C (□, ■) from use-dependent block in the presence of 250 μM internal (○, □) and symmetrical (●, ■) QX-314. External QX-314 does not influence recovery of the wild-type channel but recovery of F1236C is slowed. C, symmetrical QX-314 does not significantly affect the recovery of any of the other P-segment mutants. Bar plot of the fractional recoveries with 250 mM internal (□) and symmetrical (■) QX-314.