iNOS expression levels in WKYRs and SHRs 24 hrs after injection of 2 μg LPS. Brains slices from WKYRs (A) and SHRs (B) were stained with an anti-iNOS antibody. C (WKY) and D (SHR) represent similar micrographs counterstained with Cresyl Violet and taken at a larger magnification. Cells expressing iNOS are indicated by arrows (C) or arrow heads (neurons in 7D). Scale bar = 20 μm.