Effect of stress and lipopolysaccharide in astroglia in the substantia nigra. (A) Coronal section showing glial fibrillary acidic protein (GFAP) immunoreactivity in a vehicle-injected nonstressed animal (arrow points to injection site). A limited alteration restricted to the needle tract is observed. (B) High-magnification image of the area within the box in (A). (C) GFAP immunoreactivity in a lipopolysaccharide (LPS)-injected nonstressed animal. There is an area lacking GFAP immunoreactivity around the injection track (dotted encircled area). (D) High-magnification image of the square box in (C); the arrow shows the injection site. (E) GFAP immunoreactivity in a LPS-injected stressed animal. The area lacking GFAP immunoreactivity is bigger (dotted encircled area). (F) High magnification of the square box in panel E showing hypertrophic astrocytes surrounding the injection site. Scale bars: (A), (C) and (E), 500 μm; (B), (D) and (F), 100 μm. Abbreviations: V, vehicle; S, stress; L, lipopolysaccharide; SL, lipopolysaccharide injected into stressed animals; SLR, lipopolysaccharide injected into stressed animals treated with RU486 (mifepristone (11β-[p-(dimethylamino)phenyl]-17β-hydroxy-17-(1-propynyl)estra-4,9-dien-3-one)). (G) Quantification of the areas lacking GFAP immunoreactivity on the substantia nigra at the end of the treatments. Results are mean ± SD of at least four independent experiments expressed in millimetres squared. P < 0.001 by analysis of variance followed by least significant difference post hoc test for multiple comparisons. a, compared with vehicle (V); b, compared with stress (S); c, compared with lipopolysaccharide (L). SL, stressed animals injected with lipopolysaccharide; SLR, lipopolysaccharide injected into stressed animals treated with RU486.