LPS-induced changes in levels of mRNA related to inflammation in the hippocampus. Time-dependent changes in mRNA expression levels for IL-1β, TNF-α, iNOS, and COX-2 in hippocampus after LPS injection are shown in figures (A), (B), (C), and (D), respectively. LPS (30 μg/mouse, i.c.v.) or saline was injected into the lateral ventricle of each mouse. The mice were sacrificed 1.5, 3, 6, 9, or 24 hr after LPS injection. Their mRNA levels were assessed by real-time RT-PCR. Each mRNA level was normalized to the mRNA level of β-actin as an endogenous control. Values are shown as the mean ± S.E.M. for 3-5 mice, as shown in parentheses. Significance levels: *p < 0.05, **p < 0.01 vs. corresponding sham control (unpaired t-test).