Influence of previous housing history on the toxicity of amphetamine in aggregate mice

The lethality of d-amphetamine was studied in isolated and aggregated mice with and without previous habituation to the physical or to the physical and social environment of chronically aggregated social condition under which the toxic effects of d-amphetamine were tested. In animals without previous habituation to such environments, d-amphetamine's toxicity was greatly enhanced by social aggregation, as reported by several authors in the literature. It was found that mortality in the dose range from 5 to 90 mg/kg is mainly determined by the stimulation due to aggregation. Above 90 mg/kg, the mortalities in single and aggregated mice vary in parallel. Up from this dose, lethality is independent of the external stimulation. Previous experience with house sharing in aggregated conditions reduces aggregation mortality in proportion to the duration of the previous house sharing period.