Ethoexperimental analysis of the impact of chlordiazepoxide (CDP) on social interactions in three strains of mice.

Categories of male C57BL/10, BALB/c and Swiss mice were injected s.c. with saline or 2.5, 5 or 10 mg/kg of CDP in saline 15 min prior to encounters with peripherally anosmic Swiss male 'standard opponents'. The 10-min encounters were videotaped and subsequently analysed using a microprocessor for the times allocated to 11 broad ethological categories of behaviour. The animal's genotype had a profound effect on its response to CDP, effects being evident on attack, threat, avoidance-flee, defensive-submissive behaviour, social investigation, non-social investigation, digging and exploration-from-a-distance. Only body care and immobility showed no clear strain effect. A dose-effect of CDP was only evident on defense-submission - indeed the drug progressively increased the incidence of this behaviour in all strains.