Naturalistic behavioral assessment of anxiolytic properties of benzodiazepines and ethanol in mice.

Effects of chlordiazepoxide (CDZ), flurazepam (FLU) and diazepam (DZP) were assessed in mice by observation of digging behavior in an escape task. Reliable effects on escape latencies and number of exploratory head pokes were detected at 2 mg/kg for CDZ and FLU. DZP produced dose-dependent effects at 0.2, 0.4 and 0.6 mg/kg. Ro 15-1788 antagonized the effects of DZP (0.6 mg/kg). Ethanol (0.75 and 1.5 g/kg) produced effects similar to those of the benzodiazepines. The dynamics of this naturalistic behavior avoid the need for direct aversive stimulation or food/water deprivation to set up an approach-avoidance or conflict test. Combined with a multivariate (discriminant) analysis, the approach provides a sensitive assessment of anxiolytic drug activity.