THE EFFECTS OF ANTIPSYCHOTIC-DRUGS ON THE MESSENGER-RNA LEVELS OF SEROTONIN 5HT(2A) AND 5HT(2C) RECEPTORS

We have looked for both global and regional changes in rat brain mRNA levels encoding serotonin 5HT(2A) and 5HT(2C) receptors following acut e and chronic administration of antipsychotic drugs. In whole brain cl ozapine (30 mg/kg/day) elicited a transient rise in 5HT(2C) mRNA level s after 4 days and chlorpromazine (15 mg/kg/day) elicited a decrease o f 20% in 5HT(2A) mRNA levels after 32 days. Regionally, 32 days treatm ent with haloperidol (3 mg/kg/day), sulpiride (100 mg/kg/day) or cloza pine (10 mg/kg/day) resulted in a drop of approximate to 30-40% in 5HT (2C) mRNA levels in both cortex and cerebellum, and decreases (or non- significant trends) of 15-40% in 5HT(2A) mRNA levels in hippocampus, b rainstem and mid brain. 4 days treatment with clozapine resulted in a 40% rise of 5HT(2C) mRNA in the mid brain and a 24% rise of 5HT(2A) mR NA in the nucleus accumbens which were not found after 32 days of trea tment. These results demonstrate common chronic effects of typical and atypical drugs but unique short term effects of clozapine. (C) 1997 E lsevier Science B.V.