title: Effects of risperidone treatment on the expression of hypothalamic neuropeptide in appetite regulation in Wistar rats.
abstract: Although the use of atypical antipsychotic drugs has been successful in the treatment of schizophrenia, they can cause some complications in the long-term use, including weight gain. Patients using these drugs tend to disrupt treatment primarily due to side effects. The atypical antipsychotic mechanism of action regulates a number of highly disrupted neurotransmitter pathways in the brains of psychotic patients but may also cause impairment of neurohormonal pathways in different brain areas. In this study, we investigated the circulating levels of hypothalamic neurohormones, which are related to appetite regulation; neuropeptide Y (NPY); alpha melanocyte stimulating hormone (α-MSH); cocaine and amphetamine regulated transcript (CART); agouti-related peptide (AgRP); and leptin in male Wistar rats, which were treated with risperidone, a serotonin antagonist, for four weeks. Alterations in the mRNA expression levels of these candidate genes in the hypothalamus were also analyzed. We hypothesized that risperidone treatment might alter both hypothalamic and circulating levels of neuropeptides through serotonergic antagonism, resulting in weight gain. Gene expression studies revealed that the mRNA expression levels of proopiomelanocortin (POMC), AgRP, and NPY decreased as well as their plasma levels, except for NPY. Unexpectedly, CART mRNA levels increased when their plasma levels decreased. Because POMC neurons express the serotonin receptor (5HT2C), the serotonergic antagonism of risperidone on POMC neurons may cause an increase in appetite and thus increase food consumption even in a short-term trial in rats.
authors.affiliation: Middle East Technical University, Department of Biological Sciences, Ankara, Turkey. Electronic address: ckursungoz@gmail.com.
authors.forename: Canan
authors.initials: C
authors.lastname: Kursungoz
authors.affiliation: Department of Psychiatry, Gulhane School of Medicine, Ankara, Turkey. Electronic address: drmehmetak@gmail.com.
authors.forename: Mehmet
authors.initials: M
authors.lastname: Ak
authors.affiliation: Middle East Technical University, Department of Biological Sciences, Ankara, Turkey. Electronic address: tyanik@metu.edu.tr.
authors.forename: Tulin
authors.initials: T
authors.lastname: Yanik
mesh_terms: D054369:Agouti-Related Protein / Q000235:genetics / Q000378:metabolism; D000818:Animals; D014150:Antipsychotic Agents / Q000494:pharmacology*; D001066:Appetite / Q000187:drug effects*; D004435:Eating / Q000187:drug effects; D004797:Enzyme-Linked Immunosorbent Assay; D005786:Gene Expression Regulation / Q000187:drug effects*; D007031:Hypothalamus / Q000187:drug effects* / Q000378:metabolism; D020738:Leptin / Q000097:blood; D008297:Male; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009478:Neuropeptide Y / Q000235:genetics / Q000378:metabolism; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism*; D011333:Pro-Opiomelanocortin / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D044405:Receptor, Serotonin, 5-HT2C / Q000235:genetics / Q000378:metabolism; D018967:Risperidone / Q000494:pharmacology*; D018709:Statistics, Nonparametric; D000521:alpha-MSH; D000098882:Cocaine- and Amphetamine-Regulated Transcript Protein
chemical_list: C515197:AGRP protein, rat; D054369:Agouti-Related Protein; D014150:Antipsychotic Agents; D020738:Leptin; D009419:Nerve Tissue Proteins; D009478:Neuropeptide Y; D009479:Neuropeptides; D044405:Receptor, Serotonin, 5-HT2C; D000098882:Cocaine- and Amphetamine-Regulated Transcript Protein; D000521:alpha-MSH; D011333:Pro-Opiomelanocortin; D018967:Risperidone
keywords: Atypical antipsychotics; Hypothalamic neuropeptides; Obesity; Risperidone