We have studied the effects of the neuroleptic haloperidol and the non-benzodiazepine anxiolytics buspirone and lesopitron on the expression of c-Fos immunoreactivity in the rat forebrain. Haloperidol and buspirone administration resulted in a significant quantitative increase in the number of Fos-immunoreactive neurons in the lateral striatum and a presumable qualitative increase in the nucleus accumbens. In contrast, lesopitron did not lead to a significant increase in the c-Fos expression in the striatum. The induction of c-Fos immunoreactivity by buspirone is compatible with an interaction of this compound with D2 dopamine receptors, as documented for haloperidol. The lack of effects after lesopitron administration suggests that, in contrast with buspirone, this compound has no dopaminergic blocking activity.