Figure 6.

HP microglia isolated 1 h after behavioral experience express exaggerated IL-1β mRNA in NI rats compared with controls, but only following learning. Rats treated with PBS or E. coli on P4 were injected as adults with SAL or LPS, and received Fear Conditioning or Shock only 24 h later. Microglia were rapidly isolated 1 h later using myelin depletion and CD11b⁺ selection as described above in Figure 4. Isolated microglia were immediately lysed and total RNA isolated for RT-PCR. Relative IL-1β gene expression to GAPDH is shown. a, IL-1β mRNA expression was higher overall in NI rats (*p = 0.04) and higher in response to LPS in both groups (^#p = 0.02) (n = 6–7/group). b, There were no group differences 1 h following Shock alone (p > 0.05; n = 4–5/group). c, IL-1β mRNA was undetectable in CD11b⁻ cells collected from a separate group of rats in each condition that also received fear conditioning (n = 2/group). d, GFAP and fractalkine/CX3CL1 were robustly expressed in CD11b⁻ cells, indicating this population contained astrocytes and neurons, and was viable and responsive to LPS. Error bars indicate SEM.