Effects of the D1 receptor agonist SKF 82958 (SKF, 0.3 mg/kg, IP) on startle reflex and prepulse inhibition (PPI), in combination with the GABA-A receptor antagonist bicuculline (1 mg/kg, IP) (A-B), and in knockout (KO) mice for GABA-A δ-subunit (C-D) and pregnane X receptor (PXR) (E-F). Data are shown as means ± SEM. The number of mice in each group is indicated. Abbreviations: WT, wildtype; VEH, vehicle.