Effects of the PDE2 inhibitors Bay 60-7550 (BAY) and ND7001 on behavior in the elevated plus-maze in stressed (a) and nonstressed (b) mice. Increases in percentages open-arm entries and time indicate an anxiolytic effect, whereas decreases in these measures indicate an anxiogenic effect. Values are expressed as means ± S.E.M. (n = 6–8). #, p < 0.05 and ##, p < 0.01 compared with vehicle (VEH). **, p < 0.01 compared with restraint stress (RS). DZP, diazepam. Doses shown parenthetically are milligrams per kilogram intraperitoneally.