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.