Fig. 1. Time course of the effect of etomidate and sham (saline) injections on locomotor activity. (  A ) Effect of etomidate (10 mg/kg intraperitoneal) on exploratory and grooming behavior. The 25- to 30-min postinjection period (  gray bar ) was chosen as an appropriate time window for further experiments. (  B ) Effect of saline injection on exploratory and grooming behavior in the control (sham-injected) group. (  C ) Levels of exploratory behavior did not differ significantly in etomidate-  versus sham-injected animals during the 30-min preinjection period (  P > 0.05, unpaired  t test), but locomotor activity was significantly reduced during the 25- to 30-min postinjection period (n = 11 for etomidate and n = 10 for sham-injected animals; **  P < 0.001, unpaired  t test). IP = intraperitoneal; n.s. = not significant.