Figure 1. Chronic CTZ-treatment induces robust epileptiform activity in hippocampal cultures.

Aa and b, a representative current-clamp recording showing that chronic treatment with vehicle (0.01% DMSO) did not induce any epileptiform activity in cultured hippocampal neurons. Most of the action potentials are clearly separated, as shown in the expanded trace (Ab). Ba and b, a typical recording showing recurrent epileptiform bursts after chronic pretreatment with CTZ (5 μm, 48 h) in a pyramidal neuron. One of the epileptiform bursts in Ba was expanded in Bb, showing a train of action potentials overlaying a large depolarization shift. Ca and b, representative epileptiform burst activities induced by pretreatment (5 μm, 48 h) with kainic acid (KA), with an expanded trace shown in Cb. D, bar graphs showing the percentage of neurons manifesting epileptiform activity after pretreatment with CTZ (84.6%) and KA (60.9%). E, bar graphs showing the frequency of epileptiform bursts after pretreatment with CTZ (0.11 ± 0.01 Hz, n = 33) and KA (0.044 ± 0.012 Hz, n = 14; ***P < 0.001, Student's t test).