Haloperidol: effect of long-term treatment on rat striatal dopamine synthesis and turnover.

The short- and long-term effects of neuroleptic drugs differ both clinically and biochemically. Short-term treatment with such a drug causes a kinetic activation of striatal tyrosine hydroxylase. Long-term treatment causes a prompt activation of the enzyme which is followed by a delayed, compensatory deactivation below control levels. Tolerance also develops to the stimulating effect of haloperidol on striatal dopamine turnover.