Fig. 3. Preserved inhibitory activity in long-term propofol-treated slice cultures. The existence of a functional inhibitory network is tested by comparing excitatory field potentials recorded in the stratum pyramidale of the CA1 region before and after application of 20 μm bicuculline, a GABAAreceptor antagonist. (A ) Representative responses recorded in control cultures. (B ) Representative responses recorded in a slice culture treated for 7 days with 100 μg/ml propofol. Similar results were obtained in five other experiments (n = 6).