Fig. 3. Effect of isoflurane on lactate dehydrogenase (LDH) release. With the use of matched plates, neural stem cells were exposed to control conditions or isoflurane, 0.7, 1.4, or 2.8%, for 6 h. LDH was assayed in the media by colorimetric assay at the end of treatment or 6 or 24 h later. There was no effect of 0.7% isoflurane on LDH release (P = 0.55) (A) . Similarly, there was no effect of isoflurane, 1.4%, on LDH release (P = 0.72) (B) . In contrast, 24 h after treatment with isoflurane, 2.8%, LDH was reduced (P = 0.006) (C) . Data at each concentration were analyzed by two-way ANOVA, using treatment condition and time after treatment as the variables. Data are expressed as a percentage of matched control (mean ± SD) for N = 12 wells per treatment condition per time; *P < 0.01.