The reactivity of dopaminergic (DA) terminals in the nucleus accumbens was investigated in male rats submitted to tail-pinch or various social interactions. The DA activity was assessed by measurement of the presynaptic metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) by using differential pulse voltammetry in free moving preparations. Tail-pinch lasting 5 min or 10 min was followed by increases in DA activity of 25% and 35%, respectively. Three types of social interaction were used: interaction with an aggressive male congener, interaction with a non-aggressive male congener or interaction with a female congener. The greatest increase in dopaminergic activity (40%) was observed after the aggressive interaction. The reactivity of the DA neurons within the nucleus accumbens is, therefore, dependent on the characteristics of the behavioral situation.