The effects of aggregation on the lethality of phencyclidine in mice

The lethal effects of d-amphetamine and phencyclidine (PCP) were compared when adult male mice were placed into isolated or aggregated (12 mice/cage) conditions. The LD50 of d-amphetamine decreased approx. 30-fold between isolated (87.9 mg/kg) and aggregated (2.8 mg/kg) conditions. In contrast, PCP showed only a 1.3-fold increase in toxicity between isolated (64.5 mg/kg) and aggregated (48.4 mg/kg) conditions. These results suggest different mechanisms for the acute lethal effects of d-amphetamine and PCP in mice.