Additive effects of olanzapine and melanin-concentrating hormone agonism on energy balance.
Atypical antipsychotic drugs (AAPDs) induce hyperphagia and body weight gain as a deleterious side effect. However, the mechanism whereby these drugs affect the neuronal pathways regulating energy balance has yet to be fully elucidated. The present study was conducted to investigate the respective and interaction effects of olanzapine and agonism of the melanin-concentrating hormone (MCH) receptor (MCHR1) on body weight, food intake, adiposity and expressions of genes liable of being involved in the anabolic action of AAPDs and MCH agonism. MCH is a hypothalamic neuropeptide, which exerts stimulating effects on food intake and body weight gain. Male Wistar rats received olanzapine (1 mg/kg of rat/day per os) and/or an intracerebroventricular (ICV) infusion of a MCHR1 agonist (30 microg/rat/day) during 13 days. Food intake and body weight were recorded daily, whereas adipose tissue depots were weighed at day 13. At the end of the experiment, we also measured brain levels of the messengers RNAs (mRNAs) encoding for MCH, MCHR1, neuropeptides-Y (NPY) and agouti-related peptide (AgRP) using in situ hybridization. The 13-day treatments combining olanzapine and the MCHR1 agonist exerted additive effects in enhancing food intake and adiposity. Consistently, each treatment differently affected brain expression of genes influencing energy balance. While the MCHR1 agonist treatment increased NPY mRNA expression in the hypothalamic arcuate nucleus, olanzapine treatment specifically increased MCHR1 mRNA expression in the nucleus accumbens shell (NAcSh). AAPDs and MCH agonism exert additive effects on energy balance and selective effects on the brain expression of energy balance-related genes.
Centre de recherche de l'Institut de cardiologie et de pneumologie de Québec (Hôpital Laval) et Centre de recherche sur le métabolisme énergétique de l'Université Laval, 2725 chemin Sainte-Foy, Québec, Canada.
Benjamin
B
Guesdon
Raphaël G P
RG
Denis
Denis
D
Richard
D050154:Adiposity / Q000187:drug effects*; D054369:Agouti-Related Protein / Q000235:genetics / Q000378:metabolism; D000704:Analysis of Variance; D000818:Animals; D014150:Antipsychotic Agents / Q000494:pharmacology; D001111:Arcuate Nucleus of Hypothalamus / Q000378:metabolism; D001569:Benzodiazepines / Q000494:pharmacology*; D001835:Body Weight / Q000187:drug effects*; D004435:Eating / Q000187:drug effects*; D004734:Energy Metabolism / Q000187:drug effects*; D007028:Hypothalamic Hormones / Q000235:genetics / Q000378:metabolism; D017403:In Situ Hybridization; D015918:Infusion Pumps, Implantable; D008297:Male; D008543:Melanins / Q000235:genetics / Q000378:metabolism; D009478:Neuropeptide Y / Q000235:genetics / Q000378:metabolism; D009714:Nucleus Accumbens / Q000378:metabolism; D000077152:Olanzapine; D010907:Pituitary Hormones / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011979:Receptors, Pituitary Hormone / Q000819:agonists* / Q000235:genetics / Q000378:metabolism; D013997:Time Factors
D054369:Agouti-Related Protein; D014150:Antipsychotic Agents; D007028:Hypothalamic Hormones; D008543:Melanins; D009478:Neuropeptide Y; D010907:Pituitary Hormones; D012333:RNA, Messenger; D011979:Receptors, Pituitary Hormone; C092274:melanin-concentrating hormone receptor; D001569:Benzodiazepines; C019463:melanin-concentrating hormone; D000077152:Olanzapine