Age-related differences in the chronic and acute response to cocaine in the rat

Behavioral sensitization is known to occur in adult animals after the chronic intermittent administration of cocaine. Dopaminergic pathways in the brain, such as the nigrostriatal and mesoaccumbens projections play a vital role in this phenomenon. These pathways are rudimentary in the 1st week of life, indicating that the developing animal may be unable to respond to cocaine in the same manner as an adult. In the present study, we report that the acute response to cocaine is remarkably similar between week-old and adult rats. Pups do not, however, show locomotor sensitization to acute cocaine after chronic cocaine-administration as adults.