NADPH oxidase (NOX) activity in cultured astrocytes from WT and Tg mice. Astrocyte cultures from WT mice exposed to NH4Cl significantly increased NOX activity (1-fold by 24 h). Cultures from Tg mice treated with ammonia showed a lesser rise in NOX activity. *p<0.05 vs. WT control; † p<0.05 vs. WT NH4Cl. WT, wild type; Tg, transgenic; Cont, control, NH4+, NH4Cl. §p<0.05 vs. WT control. Error bars represent mean ± SEM.