title: Melanin-concentrating hormone in the medial preoptic area reduces active components of maternal behavior in rats.
abstract: Melanin-concentrating hormone (MCH) is an inhibitory neuropeptide mainly synthesized in neurons of the lateral hypothalamus and incerto-hypothalamic area of mammals that has been implicated in behavioral functions related to motivation. During lactation, this neuropeptide is also expressed in the medial preoptic area (mPOA), a key region of the maternal behavior circuitry. Notably, whereas MCH expression in the mPOA progressively increases during lactation, maternal behavior naturally declines, suggesting that elevated MCHergic activity in the mPOA inhibit maternal behavior in the late postpartum period. To explore this idea, we assessed the maternal behavior of early postpartum females following bilateral microinfusions of either MCH (50 and 100 ng/0.2 μl/side) or the same volume of vehicle into the mPOA. As expected, females receiving 100 ng MCH into the mPOA exhibited significant deficits in the active components of maternal behavior, including retrieving and nest building. In contrast, nursing, as well as other behaviors, including locomotor activity, exploration, and anxiety-like behavior, were not affected by intra-mPOA MCH infusion. The present results, together with previous findings showing elevated expression of this neuropeptide toward the end of the postpartum period, suggest that modulation of mPOA function by MCH may contribute to the weaning of maternal responsiveness characteristic of the late postpartum period.
authors.affiliation: Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay.
authors.forename: Luciana
authors.initials: L
authors.lastname: Benedetto
authors.affiliation: Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, NJ, USA.
authors.forename: Mariana
authors.initials: M
authors.lastname: Pereira
authors.affiliation: Sección de Fisiología y Nutrición, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay. Electronic address: anna@fcien.edu.uy.
authors.forename: Annabel
authors.initials: A
authors.lastname: Ferreira
authors.affiliation: Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay.
authors.forename: Pablo
authors.initials: P
authors.lastname: Torterolo
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D005260:Female; D007028:Hypothalamic Hormones / Q000494:pharmacology*; D007774:Lactation / Q000187:drug effects; D008425:Maternal Behavior / Q000187:drug effects*; D008543:Melanins / Q000494:pharmacology*; D010907:Pituitary Hormones / Q000494:pharmacology*; D011301:Preoptic Area; D051381:Rats; D017208:Rats, Wistar
chemical_list: D007028:Hypothalamic Hormones; D008543:Melanins; D010907:Pituitary Hormones; C019463:melanin-concentrating hormone
keywords: Lactation; MCH; Motivation; mPOA