Fig. 4. (  A ) Dose- and time-dependent sedative effects of intraperitoneal bolus administration of (1) 5 mg/kg AM 251 combined with ED⁵⁰arachidonyl-2-chloroethylamide (ACEA), (2) ED⁵⁰ACEA combined with ED⁵⁰etomidate (Eto), and (3) 5 mg/kg AM 251 combined with ED⁵⁰ACEA and ED⁵⁰etomidate. The cannabinoid¹receptor antagonist AM 251 reversed the sedative component of ACEA both when ACEA was administered alone and in combination with etomidate. (  B ) Dose- and time-dependent sedative effects of (1) 5 mg/kg AM 251 combined with 0.2 mg/kg lipid emulsion, (2) vehicle combined with ED⁵⁰etomidate, and (3) 5 mg/kg AM 251 combined with ED⁵⁰etomidate. Thus, the cannabinoid¹receptor antagonist had no effect on etomidate-induced sedation. Time on the Rota-Rod (in seconds) (Rota-Rod; Ugo Basile, Comerio, Italy) is shown from −10 min to 90 min after administration. AM 251 and vehicle control were administered at t =−10 min, and ACEA, etomidate, and lipid emulsion at t = 0. Each  data point provided represents the mean of six to eight animals, including the respective SEM indicated by the  whiskers .