Fig. 3. Rats were subjected to 10 min of severe forebrain ischemia while anesthetized with fentanyl–nitrous oxide (F/N) or isoflurane (ISOF) and were allowed to survive for 5 days, 3 weeks, or 3 months. Percent alive hippocampal CA1 neurons, as assessed with acid fuchsin–celestine blue staining, are shown for the respective recovery intervals. A difference was present between anesthetic groups at 5 days after ischemia (P = 0.011). There was no difference between groups at 3 weeks or 3 months. Horizontal bars = group mean values; open circles = values for individual rats.