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. 2016 Jul 13;36(28):7511–7522. doi: 10.1523/JNEUROSCI.0462-16.2016

Figure 3.

Figure 3.

Ala1632Gly increases the number of spontaneously firing small DRG neurons and reduces current threshold for evoked firing. A, Representative recording of a spontaneously firing small DRG neuron expressing Ala1632Gly. The trace is a record of activity over 30 s without current injection. Bar graph represents a 3.2-fold increase in the proportion of spontaneously firing DRG neurons expressing Ala1632Gly (orange) compared with WT hNav1.7 channels (blue). B, Current threshold was significantly reduced in neurons expressing Ala1632Gly channels. C, Responses of a current-clamped small DRG neuron transfected with WT hNav1.7 channels to a series of subthreshold (180–190 pA) and suprathreshold depolarizing current steps (195 and 200 pA). Starting at a subthreshold stimulus, the current amplitude was increased in 5 pA increments to stimulus strength above threshold. The current threshold was 195 pA for this neuron. D, The same threshold protocol was applied to a small DRG neuron transfected with hNav1.7-A1632G channel. The current threshold was 105 pA for this neuron. Arrows indicate the current amplitude used to elicit the labeled response. Inset, Superimposed action potential waveforms of WT (blue) and Ala1632Gly expressing neurons (orange). Error bars indicate SEM. *p < 0.05.