An intrastriatal injection of the D2 quinpirole agonist facilitates learning about the task of labyrinthe radial win-stay (Packard and White, 1991). Three experiments are carried out to investigate further the involvement of D2 dopaminergic receptors in this type of learning and also to check the impact of this effect on the expression of the proto-oncogen c-fos. In the first study we manage to replicate the enabling effect of quinpirole, but it has weaknesses and we repeat the procedure in a second study. In this second study, an additional group is previously injected i.p. by antagonist D2 sulpiride. The results show that quinpirole injection does not improve performance and that the group previously receiving sulpiride injection surprisingly improves performance. A third study is repeated. Again, the facilitating effect of quinpirole is not observed and the sulpiride leads to an insignificant improvement in performance. The impact of these procedures on the expression of c-fos was not carried out because it had failed to control the desired effect. The discussion focuses on identifying the possible reasons for these difficulties in observing the facilitating effect of quinpirole.