The effect of chlordiazepoxide on measures of activity and anxiety in Swiss-Webster mice in the triple test

The effects of the anxiolytic drug chlordiazepoxide (CDZ) on general activity and anxiety-related behaviour of male and female Swiss-Webster mice were investigated in the triple test, which combines the open field (OF), elevated-plus maze (EPM) and the light-dark box (LDB). Mice were injected with saline or CDZ (1.0, 7.5 or 15.0 mg/kg) and their behaviour was observed for 15 min in the triple test on each of two days. On day 1, increasing doses of CDZ increased open arm exploration and total distance travelled, and decreased risk assessments in the EPM. In the LDB, CDZ increased time in the light compartment and number of transitions between compartments. In spite of habituation to the apparatus, CDZ increased the number of transitions in the LDB, increased percent time in the open arms and total distance travelled in the EPM on day 2. Thus, there was a significant effect of CDZ in the triple test on both days, even though there was habituation to the apparatus after day 1. These results show that the drug effect was independent of the day effect and that there was no one-trial tolerance effect in the triple test of anxiety.

► The triple test combines the open field, elevated-plus maze and light-dark box. ► Mice received one of four doses of chlordiazepoxide and tested on two trials. ► Chlordiazepoxide had a significant effects in the triple test on both days. ► This effect was independent of the day effect and we found no tolerance effect.