Effects of COX-1 deficiency on LPS-induced activation of microglia. (A-P) Representative photomicrographs of CD11b (A-D), CD45 (E-H), FcγRII/III (I-L), and SRA (M-P) immunohistochemistry in the hippocampus for COX-1+/+ and COX-1−/− mice that received icv injection of LPS or vehicle 24 h before sacrifice. The insets of A-H, J, L, N, and P show morphology of microglia at higher magnification. Scale bar, 100 μm (A-P).