Increased mesolimbic dopamine binding following chronic haloperidol treatment.

It is well documented that chronic neuroleptic treatment creates a dopamine receptor supersensitivity in the striatum. The present study examined the effect of chronic neuroleptic treatment on mesolimbic dopamine receptor binding. Rats received either 0.5 mg/kg of haloperidol, 50 mg/kg of sodium phenobarbital, or 0.9% saline daily for 21 days. One week following the last injection, the rats were sacrificed and the septi were removed for the 3H-dopamine binding assay. Haloperidol treatment resulted in a 52% increase in 3H-dopamine binding in the septum, whereas phenobarbital treatment caused no significant change.