DIFFERENTIAL-EFFECTS OF HALOPERIDOL AND 2 ANXIOLYTIC DRUGS, BUSPIRONEAND LESOPITRON, ON C-FOS EXPRESSION IN THE RAT STRIATUM AND NUCLEUS-ACCUMBENS

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 buspi rone 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 contras t, lesopitron did not lead to a significant increase in the c-Fos expr ession in the striatum. The induction of c-Fos immunoreactivity by bus pirone is compatible with an interaction of this compound with D-2 dop amine receptors, as documented for haloperidol. The lack of effects af ter lesopitron administration suggests that, in contrast with buspiron e, this compound has no dopaminergic blocking activity.