Neurochemical effects of chronic co-administration of ritanserin and haloperidol: comparison with clozapine effects.
The effects of chronic treatment with clozapine (20 mg/kg per day), ritanserin (0.5 mg/kg per day), haloperidol (0.5 mg/kg per day), or the combination of haloperidol and ritanserin, on dopamine (DA) and serotonin (5-HT) metabolism were studied. Chronic haloperidol treatment decreased DA metabolism in nucleus caudatus. Chronic ritanserin treatment failed to alter striatal or mesolimbic DA metabolism but decreased the concentrations of 5-HT and 5-hydroxyindoleacetic acid in the nucleus raphe dorsalis. The effects of chronic haloperidol were not altered by concomitant ritanserin administration. In comparison, chronic clozapine treatment affected neither DA nor 5-HT metabolism. These results show that the biochemical effects of chronic haloperidol treatment on the major ascending DA neurons cannot be modulated by concomitant 5-HT2 receptor blockade.
Lappalainen
J
J
Department of Pharmacology, University of Turku, Finland.
Hietala
J
J
Koulu
M
M
Syvälahti
E
E
D000818:Animals; D003024:Clozapine / Q000008:administration & dosage / Q000494:pharmacology*; D004298:Dopamine / Q000378:metabolism*; D004338:Drug Combinations; D006220:Haloperidol / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D009714:Nucleus Accumbens / Q000378:metabolism; D010880:Piperidines / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D016713:Ritanserin; D012701:Serotonin / Q000378:metabolism*; D013378:Substantia Nigra / Q000378:metabolism; D013997:Time Factors
D004338:Drug Combinations; D010880:Piperidines; D016713:Ritanserin; D012701:Serotonin; D003024:Clozapine; D006220:Haloperidol; D004298:Dopamine