Increases in cortical neuropeptide Y and somatostatin concentrations following haloperidol-depot treatment in rats.
The concentrations of neuropeptide Y (NPY) and somatostatin (SS) have been said to be altered in the brain and cerebrospinal fluid of schizophrenic patients. This alteration could result from the neuroleptic treatment. Therefore, it is of interest to evaluate effects of long-term treatment with neuroleptics on the peptide concentrations in the brain. Haloperidol (HPD) is one of the most frequently used neuroleptics for the treatment of schizophrenia. We determined regional brain levels of NPY and SS following HPD administration in the rat. A single intraperitoneal injection of HPD, at a dose of 1 mg/kg, did not affect peptide levels in the brain regions studied. Four weeks after an intramuscular deposit injection of HPD decanoate, 50 mg/kg, NPY concentrations were increased in a number of areas of the cerebral cortex. SS content was also significantly increased in the lateral prefrontal cortex and anterior cingulate cortex. Both peptide levels were decreased in the striatum. These results suggest that the reduction found in these peptides' levels in the cerebral cortex of the brain from schizophrenic patients may not be the consequence of HPD treatment and that these peptides' levels might be increased in the cerebral cortex of the brain of schizophrenic patients following the treatment with HPD.
Department of Psychiatry, Kobe University School of Medicine, Japan.
K
K
Sakai
K
K
Maeda
K
K
Chihara
H
H
Kaneda
D000818:Animals; D002540:Cerebral Cortex / Q000187:drug effects* / Q000378:metabolism; D003692:Delayed-Action Preparations; D018492:Dopamine Antagonists / Q000494:pharmacology*; D006220:Haloperidol / Q000494:pharmacology*; D008297:Male; D009478:Neuropeptide Y / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013004:Somatostatin / Q000378:metabolism*
D003692:Delayed-Action Preparations; D018492:Dopamine Antagonists; D009478:Neuropeptide Y; D013004:Somatostatin; D006220:Haloperidol