Differential effect of acute and chronic haloperidol administration on dopamine turnover in rat nigrostriatal and retinal dopaminergic neurons.

Haloperidol-induced increases in DOPAC and HVA declined in the striatum but remained unchanged in the retina after chronic pretreatment with haloperidol (1-4 weeks). DA concentrations were unaffected in the striatum but decreased in the retina after acute or chronic haloperidol administration. Light stimulation increased both retinal DA and DOPAC. The findings indicate that acute and chronic haloperidol affect nigrostriatal and retinal DA neurons differentially. In addition, DA neurons in retina respond differently to activations by haloperidol and light.