Neuregulin-1 blocks DFP-induced microglia activation in the hippocampus. Labeling of adjacent sections from the dentate gyrus of the hippocampus showed that in DFP intoxicated animals, ED-1 immunoreactivity (A; arrows) coincided with regions of FJB stained neurons (C). In contrast, in DFP intoxicated animals pretreated with NRG-1, virtually no ED-1 immunoreactivity (B) or FJB staining (D) was observed. H, hilus; GL, granule cell layer. Stereotaxic coordinate = bregma −3; Scale bar = 50 μm.