Fig. 5. In the presence of picrotoxin, isoflurane does not block long-term potentiation (LTP) induction. Pooled data of eight experiments. Same experiment as in figure 4, except that picrotoxin (50 μm) was present during the whole experiment. To prevent epileptic discharges of field excitatory postsynaptic potentials (fEPSPs), field responses were evoked using test pulses of intermediate intensity. The arrow indicates the time of tetanic stimulation. Data points have been calculated as in figure 3. ISO = isoflurane.