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 antipsychotic drugs on thalamic sites. METHOD: Nine rats were given acute doses of the typical neuroleptic haloperidol (N = 3), the atypical neuroleptic clozapine (N = 3), or a drug-free vehicle (N = 3). Cellular activation was assessed by using immunohistochemistry to determine expression of the immediate response gene c-fos. RESULTS: Both antipsychotic drugs induced increased Fos immunoreactivity, suggesting increased activity in cells of the midline nuclei of the thalamus. CONCLUSIONS: The shared clinical effects of antipsychotic drugs may be mediated in part through actions on the thalamus.