Figure 1

LPS increases microglial nitrite production. Rat microglia cells were incubated in the presence (▲) or absence (○) of LPS (1 ng/ml) for indicated times. NO production was assessed (A) indirectly by measuring nitrite levels in the incubation medium; or (B) directly by the oxidation of H₂DCF added to the cells at the end of the experiment. For DCF studies, in each experimental group NOS2 activity was inhibited in parallel samples by preincubating cells 20 min with the selective NOS2 inhibitor, 2-amino-dihydro-6-methyl-4H-1,3-thiazine (AMT, 100 μM). Data are means ± s.e.m. of 3 different experiments. *** and *, P < 0.001 and 0.05 versus control; two-way ANOVA followed by Bonferroni's post hoc test.