FIG. 4.

Effects of sodium channel inhibitors on depolarization-induced action potentials in neuron-like cells differentiated from neural stem cell–like cells. (A) The depolarization-induced action potentials were inhibited by 3.5 mM lidocaine. Notice that the inhibition reversed after washing with control saline [(artificial cerebrospinal fluid (aCSF)]. (B) Tetrodotoxin (TTX, 1 μM) had little effect on the action potential or the steady-state currents, suggesting that the spikes are generated by TTX-resistant voltage-gated sodium channels. Resting membrane potential (mV) is indicated to the left of the voltage recordings. Recordings are representative examples.