(A) Nitrite was measured 24 hours after 90-minute incubations under the designated conditions. ZnCl2, 30 μM; aminoguanidine (AG), 1 mM; PJ-34, 400 nM; LPS, 50 ng/ml. n = 4; * p < 0.05. (B) Western blot shows F4/80 expression at 160 kD (top) and β-actin loading control (bottom). Vertical lines denote independently prepared blots. Cultures were prepared from wild-type, PARP-1−/−, or p47phox−/− microglia, after treatment as denoted on the bar graph. Abbreviations as in (A). Graph indicates quantified data from n =3, normalized to expression in control, wild-type cells. * p < 0.05 versus wild-type control.