Fig. 6.

Effect of 30 nM and 100 nM VX-548 on action potential firing. (A) Example of a neuron testing successive application of 10 nM, 30 nM, and 100 nM VX-548 on firing evoked by a 1-s current pulse. (B) The beginning of the record on a faster time scale, showing the earlier firing of the second spike in 10 nM, 30 nM, and 100 nM VX-548. (C) Number of action potentials evoked by 1-s current injections of different magnitudes in this neuron. Note increased firing for current injections below 500 pA. (D) Collected data for the maximum number of action potentials evoked by a series of 1-s current injections in 8 neurons in which concentrations of 10 nM, 30 nM, and 100 nM VX-548 were applied successively. Dashed line drawn at 1 action potential.