Figure 9.

(a) Spontaneous activity in a current clamped cell superfused with 10 μM picrotoxinin (horizontal bar). Note the selective, progressive block of IPSPs (downward deflections) and the increased incidence of spiking/burst firing in the treated cell. (b) One of these bursts at higher resolution: these paroxysmal depolarizing shifts are typical features of disinhibition in the cultured cortical cells. (c) 10 μM12,14-Cl₂DHA (bar) did not evoke this type of epileptiform activity. In all cells examined the compound blocked all synaptic currents and spontaneous spiking (after transient periods of hyperexcitation). (d) Faster sweeps (from the cell depicted in c) demonstrating spontaneous synaptic events and action potentials pretreatment (upper trace) and the lack of physiological activity after prolonged exposure to 12,14-Cl₂DHA.