Fig. 1. The D1 receptor agonist chloro-APB decreases time to emergence from isoflurane anesthesia. A , Rats inhaled isoflurane (1.5%) and received normal saline, chloro-APB (3 mg/kg IV), or the D2 receptor agonist quinpirole (5 mg/kg IV) after 40 min (solid arrow ). Five minutes later, the animals were removed from the anesthetizing chamber (dashed arrow ). Time to emergence was defined as the time from termination of isoflurane to return of righting (i.e. , all four paws touching the floor). B , Scatter plot of time to emergence for rats that received normal saline, chloro-APB, and quinpirole (n = 6 each). The lines represent the medians. **P < 0.01.