Figure 6From: Mutations at opposite ends of the DIII/S4-S5 linker of sodium channel NaV1.7 produce distinct pain disorders Excitability is increased in DRG neurons transfected with the P1308L or V1298F mutant channels. A, Responses of DRG neurons expressing WT, P1308L, or V1298F channels to a series of current stimuli with 5-pA increment. DRG neurons expressing P1308L channels showed a lower action potential threshold (P1308L: 122 ± 10 pA, n = 50, p < 0.001 vs WT: 188 ± 14 pA, n = 38), while expression of V1298F did not significantly change the action potential threshold (V1298F: 154 ± 18 pA, n = 27, p = 0.215 vs WT). B, The mean firing frequency of DRG neurons expressing WT, P1308L, or V1298F channels in response to a series of 1-s current injections ranging from 25 to 500 pA with 25-pA increments. Both P1308L and V1298F elevated firing frequency of transfected DRG neurons. * indicates p < 0.05 for P1308L vs WT channels, * indicates p < 0.05 for V1298F vs WT channels. C, Representative traces showing responses to current stimuli approximately 1.5× (top) and 2× (bottom) action potential threshold, recorded from DRG neurons expressing WT, P1308L, or V1298F channels from (A).Back to article page