An analysis of drug effects in mice exposed to a simple novel environment

The effects of orally administered drugs on the ambulatory activity of mice placed into a novel environment were investigated. Chlordiazepoxide or diazepam increased ambulatory activity; this effect occurred during the initial minutes of testing but in later minutes activity was reduced. Amylobarbitone, meprobamate or high doses of atropine produced more sustained increases in activity. Ambulatory activity was not increased by chlordiazepoxide or amylobarbitone in mice familiar with the test situation; in these conditions activity was increased by meprobamate and atropine. The observed differences between drugs were discussed in terms of habituation and interactions with environmental novelty.