title: Tuning the brain for motherhood: prolactin-like central signalling in virgin, pregnant, and lactating female mice.
abstract: Prolactin is fundamental for the expression of maternal behaviour. In virgin female rats, prolactin administered upon steroid hormone priming accelerates the onset of maternal care. By contrast, the role of prolactin in mice maternal behaviour remains unclear. This study aims at characterizing central prolactin activity patterns in female mice and their variation through pregnancy and lactation. This was revealed by immunoreactivity of phosphorylated (active) signal transducer and activator of transcription 5 (pSTAT5-ir), a key molecule in the signalling cascade of prolactin receptors. We also evaluated non-hypophyseal lactogenic activity during pregnancy by administering bromocriptine, which suppresses hypophyseal prolactin release. Late-pregnant and lactating females showed significantly increased pSTAT5-ir resulting in a widespread pattern of immunostaining with minor variations between pregnant and lactating animals, which comprises nuclei of the sociosexual and maternal brain, including telencephalic (septum, nucleus of the stria terminalis, and amygdala), hypothalamic (preoptic, paraventricular, supraoptic, and ventromedial), and midbrain (periaqueductal grey) regions. During late pregnancy, this pattern was not affected by the administration of bromocriptine, suggesting it to be elicited mostly by non-hypophyseal lactogenic agents, likely placental lactogens. Virgin females displayed, instead, a variable pattern of pSTAT5-ir restricted to a subset of the brain nuclei labelled in pregnant and lactating mice. A hormonal substitution experiment confirmed that estradiol and progesterone contribute to the variability found in virgin females. Our results reflect how the shaping of the maternal brain takes place prior to parturition and suggest that lactogenic agents are important candidates in the development of maternal behaviours already during pregnancy.
authors.affiliation: Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, Av. de Vicent Sos Baynat, s/n, 12071, Castelló de la Plana, Spain.
authors.forename: Hugo
authors.initials: H
authors.lastname: Salais-López
authors.affiliation: Departaments de Biologia Cel·lular i Biologia Funcional, Facultat de Ciències Biològiques, Universitat de València, C/ Dr. Moliner, 50, 46100, Burjassot, Spain.
authors.forename: Enrique
authors.initials: E
authors.lastname: Lanuza
authors.affiliation: Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, Av. de Vicent Sos Baynat, s/n, 12071, Castelló de la Plana, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Agustín-Pavón
authors.affiliation: Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, Av. de Vicent Sos Baynat, s/n, 12071, Castelló de la Plana, Spain. femartin@uji.es.
authors.forename: Fernando
authors.initials: F
authors.lastname: Martínez-García
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D005260:Female; D007774:Lactation; D008425:Maternal Behavior / Q000502:physiology*; D051379:Mice; D009474:Neurons / Q000378:metabolism; D010052:Ovariectomy; D010766:Phosphorylation; D011247:Pregnancy; D011388:Prolactin / Q000378:metabolism / Q000502:physiology*; D051381:Rats; D050799:STAT5 Transcription Factor / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction
chemical_list: D050799:STAT5 Transcription Factor; D011388:Prolactin
keywords: CD1 mice; Maternal aggression; Maternal care; Placental lactogens; Sociosexual brain; pSTAT5