Fig. 7. Effect of isoflurane on number of neural stem cells (NSCs) in culture. With the use of matched plates, NSCs were exposed to control conditions or isoflurane, 0.7, 1.4, or 2.8%, for 6 h. The absolute number of cells was determined 24 h after anesthesia based on the number of Hoechst staining cell nuclei. NSCs in culture proliferate over time, leading to an increase in the number of control cells at 6 and 24 h after treatment (P < 0.001). Data expressed as a percentage of end of anesthesia controls and analyzed using a one-way ANOVA (A) . Consistent with its antiproliferative effect, isoflurane decreased the number of NSCs present 24 h after treatment relative to the number of cells in control plates (P < 0.001). Data expressed as a percentage of their time-matched controls and analyzed using a one-way ANOVA. Data are expressed as mean ± SD for N = 12 wells per treatment condition (eight images per well) (B) .