Fig. 4. Dose-response of isoflurane effects on nitrite production. The mouse C8-B4 microglial cells were incubated with 10 ng/ml lipopolysaccharide (LPS) and 10 U/ml of interferon γ (IFNγ) for 24 h. Cells were exposed to 1, 2, or 3% isoflurane for 1 h immediately after the initiation of the lipopolysaccharide and IFNγ stimulation. The culture medium was collected for nitrite measurement. Results are mean ± SD (n = 15). * P < 0.05 compared to control. ˆ P < 0.05 compared to lipopolysaccharide plus IFNγ only.