Long-term effects of early diazepam exposure on social differentiation in adult male rats subjected to the diving-for-food situation.

The present study was designed to investigate the consequences of a chronic diazepam (DZ) exposure (10 mg/kg/day) during the first 3 weeks of life on social behavior of adult male rats measured in a situation of restricted access to food, the diving-for-food model. The treatment had no long-term effects on the acquisition of social roles related to feeding. However, DZ-exposed rats were less efficient than controls in carrying food from the feeder to the cage during the 1st session but were able to adapt and improve their performances during the 2nd one. In the home cage, DZ-exposed rats were more aggressive toward conspecifics than controls and compensated for their deficit of food by stealing it from the others. These results suggest that an early DZ exposure has long-term consequences on social behavior of rats, possibly reflecting a reduction of the level of emotionality.