Changes in anxiety levels are followed by changes in behavioral strategy in mice subjected to stress and in the extent of stress-induced analgesia.

The experiments reported here demonstrated that corasol increased the extent of analgesia induced by stress and decreased the duration of immobility in mice in a forced swimming test in cold water. Administration of diazepam led to the opposite changes and counteracted the actions of the anxiogen. The effects of the anxiolytic were more apparent in NMRI than mongrel mice, while in mongrel mice the effects of the anxiogen were more marked. Changes in measures following administration of agents were reciprocal in nature. These results lead to the conclusion that that these changes are determined by the level of anxiety, and that the strain differences between mongrel and NMRI mice are also linked with this factor.