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Compelling evidence demonstrates that heightened sensation seeking during adolescence, together with risk taking and reckless behaviors, is the major cause of morbidity and mortality among teenagers.It is considered that much brain development during adolescence occurs in brain regions and systems that are critically involved in the perception and evaluation of risk and reward.Though, there is substantial evidence that adolescents engage in dangerous activities, including drug abuse, despite knowing and understanding the risks involved.One explanation might be the impulsive trait that characterizes adolescence;another could be a greater incentive for rewards or a reduced sensitivity for aversive effects of drugs of abuse.In this study, we assessed motor impulsivity in juvenile rats, by comparison with adults, and compared the respective behaviors of both groups in a discrete-choice procedure in which animals had to choose between intravenous infusions of cocaine and drops of 0.2% saccharine in tap water.In the 5-choice-serial-rankingtime-task (5-CSRTT), we demonstrated that, despite similar performances in terms of accuracy, juvenile rats displayed an increased number of premature responses compared to adults confirming our original assumption.However, unexpectedly, both juvenile and adult rats exhibited the same preference for saccharine over cocaine, whether or not they had been exposed to a chronic stress during the three weeks preceding the test.Our results show that despite a heightened motor impulsivity, juvenile rats do not exhibit any vulnerability to abuse cocaine in our experimental procedure.These observations also open the discussion regarding the addictive potential of sweetened solutions, and the consequences of early exposure to soft drinks during childhood and adolescence.