The effect of haloperidol on D2 dopamine receptor subtype mRNA levels in the brain.

Chronic neuroleptic treatment induces an increase in the density of D2 dopamine receptors in the striatum. The effect of prolonged administration of haloperidol on mRNA levels of the short (D2S) and long (D2L) isoforms of the D2 dopamine receptor and the D3 dopamine receptor in different brain regions was examined. Haloperidol caused a significant rise in both D2L and D2S mRNA levels in the striatum, but had no effect on D3 mRNA levels. This rise was restricted to the striatum, showing that the effect of haloperidol on dopamine receptor mRNA is both subtype- and tissue-specific.