Fig. 2.

Distance traveled in the open field reveals no hypoactivity or lack of mobility in α_2A-AR-KO mice compared with WT mice but a sedative effect of imipramine in both genotypes. WT (open symbols) or α_2A-AR-KO (filled symbols) mice were injected with either saline (circles) or imipramine (squares) (see Materials and Methods) and placed in the open field mobility chambers for 20 min sessions. Distance traveled in centimeters was recorded in each of four 5 min blocks across the session (mean ± SEM, n = 11–16 mice per group). Genotype effect,F_(1,49) = 0.324, p= 0.5715. Drug effect, F_(1,49) = 5.48,p = 0.0233. Time block effect,F_(3,147) = 16.5, p< 0.0001. The interaction effects were not significant.