Figure 3.
α1-receptor blockade prevents MPH-induced improvement in sustained attention. Animals were treated with either: 1) 2.0 mg/kg MPH; 2) 0.5 mg/kg of the α1-receptor antagonist, prazosin; 3) 0.5 mg/kg prazosin + 2.0 mg/kg MPH. Shown are values for d′, expressed as a change from baseline. 2.0 mg/kg MPH improved performance in this task, similar to that seen in Figure 1. Treatment with prazosin had no effect on sustained attention performance. In contrast, this dose of prazosin completely blocked the facilitating effects of MPH on sustained attention. **P < 0.01 vs. baseline; +P < 0.05 vs. vehicle.