Figure 4.

Locomotor sensitization in mice pre-exposed to cocaine during adolescence and adulthood. Distance traveled in response to challenge injections of 0 mg/kg (a), 10 mg/kg (b), and 20 mg/kg (c) of cocaine following pre-exposure to cocaine or saline during adolescence or adulthood. Mice pre-exposed to cocaine during adolescence showed an enhanced response to 10 and 20 mg/kg doses of cocaine during the first 15 min of the test session compared with mice exposed to cocaine during adulthood (*p < 0.05). Values are means ±SEM.