Drug-induced home cage conspecifics' behavior can potentiate behavioral sensitization in mice

The effect of home cage conspecifics' behavior on locomotor sensitization to amphetamine (AMP) or ethanol (ETOH) were investigated. Female mice were repeatedly treated with saline or AMP (2.0 mg/kg for 13 days - Experiment 1) or saline or ETOH (1.8 g/kg for 21 days - Experiment 2) in home cages where all the animals had the same treatment (homogeneous home cages - HOM-HC) or in home cages where half of the animals were drug-treated and half of them were saline-treated (heterogeneous home cages - HET-HC). Behavioral sensitization was evaluated by the quantification of open-field locomotor activity after AMP or ETOH challenge injection, respectively. In both experiments, behavioral sensitization was potentiated in HOM-HC maintained animals. These results suggest that the behavioral sensitization phenomenon can be modified by home cage conspecifics' behavior.