Effect of -NAME on NOx levels and NORT performance in WT mice. -NAME (10, 25, or 50 mg/kg; i.p.) was administered 30 min before vehicle (10 ml/kg, i.p.) or D. alfa (25 μg/kg i.p.). NORT was performed 3 h after D. alfa treatment, and then hippocampi were subjected to measurement of NOx levels. (a) Dose-dependent inhibition of D. alfa (25 μg/kg, i.p.)-induced increases in nitrate and nitrite (NOx) levels in the hippocampus of wild-type mice by -NAME. NOx levels (μM/mg (protein)) are shown in the bar graph as mean±SEM. V; vehicle (10 ml/kg, i.p.); Darbepoetin alfa, D. alfa (25 μg/kg, i.p.), V/−: N=5, V/+: N=6, 10 mg/+: N=5, 25 mg/+: N=6, 50 mg/+: N=5. One-way ANOVA with Newman-Keuls test, *p<0.05. (b) Object exploration time in the sample phase. Each bar represents the mean±SEM. Animals that received vehicle or -NAME spent equivalent amounts of time exploring objects during sample phase. (c) Discrimination ratio (d2) during the choice phase for animals injected with vehicle (10 ml/kg, i.p.) or -NAME (10, 25, or 50 mg/kg; i.p.). Each bar graph represents the mean±SEM. There were no significant differences between groups that received vehicle (10 ml/kg, i.p.) or -NAME (10, 25, or 50 mg/kg; i.p.), one-way ANOVA. (d) Percent time spent exploring the novel object during the choice phase. Each bar graph represents the mean±SEM. V; vehicle (10 ml/kg); Darbepoetin alfa, D. alfa (25 μg/kg), V/−: N=5, V/+: N=6, 10 mg/+: N=5, 25 mg/+: N=6, 50 mg/+: N=5. There were no statistically significant differences among the groups, one-way ANOVA.