Dopamine D2-receptor mRNA level in rat striatum after chronic haloperidol treatment.

Chronic treatment with haloperidol, a D2-receptor antagonist and a neuroleptic, increases the number of D2-receptors in rat striatum. However, there have been inconsistent reports on the D2-receptor mRNA level, one showing the increase in the mRNA level and another detecting no changes. Furthermore, they did not distinguish the two isoforms of D2-receptor, D2A and D2B. In the present work, both D2- and DeA-receptor mRNA levels in rat striatum were estimated after chronic administration of haloperidol. There was, within the sensitivity of the assay, no significant increase in either of them between 3 and 24 h after the last administration. This suggests that chronic haloperidol treatment does not affect the transcriptional regulation of the D2-receptor gene or the alternative splicing process of its transcripts.