Figure 1.

Time to return of the righting reflex in mice anesthetized with the α2 agonist xylazine, in combination with ketamine, after intraperitoneal administration of either of the α2 antagonists atipamezole (1 mg/kg IP) and yohimbine (1.5 mg/kg IP) or saline (control). At these dosages, atipamezole (mean ± 1 SD, 10.3 ± 6.5 min) resulted in the most rapid recovery of the mice to sternal recumbency, allowing for prompt return of the mice to the home cage after anesthesia, compared with yohimbine (21.3 ± 5.6 min) and saline (38.2 ± 7.5 min). The 3 data points designated by triangles indicate a technical error, in which the antagonist was given at 10 min, rather than 15 min, after the anesthetic combination.