Homovanillic acid in caudate and pre-frontal cortex following acute and chronic neuroleptic administration.

Homovanillic acid (HVA) was measured in rat caudate and pre-frontal cortex after single and repeated doses of several types of neuroleptic drugs. Twice daily administration of low or high doses of haloperidol, fluphenazine, or (-) sulpiride resulted in greater tolerance to the initial HVA increase in caudate compared to prefrontal cortex.