THE THALAMUS AS A SITE OF ACTION OF ANTIPSYCHOTIC-DRUGS

Objective: Because recent data suggest that there are abnormalities of the thalamus in schizophrenia, the authors tested the effects of anti psychotic drugs on thalamic sites. Method. Nine rats were given acute doses of the typical neuroleptic haloperidol (N=3), the atypical neuro leptic clozapine (N=3), or a drug-free vehicle (N=3). Cellular activat ion was assessed by using immunohistochemistry to determine expression of the immediate response gene c-fos. Results: Both antipsychotic dru gs induced increased Fos immunoreactivity, suggesting increased activi ty in cells of the midline nuclei of the thalamus. Conclusions: The sh ared clinical effects of antipsychotic drugs may be mediated in part t hrough actions on the thalamus.