The effect of benzodiazepines and atropine on exploratory behaviour and motor activity of mice.

1. Male albino mice were watched in red light on a tunnel board to test exploration and their motor activity was assessed in an open cage, 30 min after intraperitoneal injection of drugs.2. Atropine and methylatropine 5 or 10 mg/kg did not alter the motor activity of the mice, while chlordiazepoxide 25 or 50 mg/kg and diazepam 10 or 20 mg/kg increased the activity, especially at the lower of the two doses used.3. All the compounds used except methylatropine adversely affected the exploratory behaviour.4. When atropine 10 mg/kg was given with the benzodiazepines, the activity of the mice was reduced and exploratory behaviour was further impaired. Methylatropine did not have this effect.