title: The effect of intracerebroventricular infusions of ghrelin or short fasting on the gene expression and immunoreactivity of neuropeptide Y in the hypothalamic neurons in prepubertal female lambs: a morphofunctional study.
abstract: The role of exogenous ghrelin in the regulation of neuropeptide Y (NPY) neuronal system in the hypothalamus of intact lambs has not been yet determined. The aim of present study was to investigate the effects of intracerebroventricular infusion of ghrelin or short fasting on the secretory activity of the NPY neurons in the hypothalamus of prepubertal female sheep. Animals (n=30) were randomly divided into three groups, two groups were fed standard diet and one group was fasted for 72h. One group fed standard diet and fasted group were infused to the 3rd ventricle of the brain with vehicle, while the remaining group fed standard diet was infused with ghrelin (25μg/120μl/h) for 6h during three consecutive days. Immediately after the treatment, tissues were collected. Parts of the brains were fixed in situ for further immunohistochemical analysis, and remaining parts were frozen for RT-PCR analysis. Both, fasting and ghrelin infusion elicited the same kind of changes in the mRNA and intra-neuronal levels of the NPY hypothalamic neurons. Namely, the expression of NPY mRNA in the medial basal hypothalamus and immunoreactivity of NPY in the arcuate and periventricular nuclei increased in fasted and standard fed with ghrelin's infusion groups compared to standard fed sheep (P<0.05). These data demonstrate that ghrelin takes part in the mechanisms linking the nutritional status with an activity of the hypothalamic NPY at the level of the central nervous system by stimulating NPY secretion in sheep.
authors.affiliation: The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Jabłonna, Poland. j.polkowska@ifzz.pan.pl
authors.forename: Jolanta
authors.initials: J
authors.lastname: Polkowska
authors.forename: Alina
authors.initials: A
authors.lastname: Gajewska
authors.forename: Marta
authors.initials: M
authors.lastname: Wańkowska
authors.forename: Tomasz
authors.initials: T
authors.lastname: Misztal
authors.forename: Anna
authors.initials: A
authors.lastname: Wójcik-Gładysz
mesh_terms: D000367:Age Factors; D000818:Animals; D005215:Fasting / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation; D054439:Ghrelin / Q000008:administration & dosage*; D007031:Hypothalamus / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D057967:Infusions, Intraventricular; D009474:Neurons / Q000737:chemistry / Q000378:metabolism*; D009478:Neuropeptide Y / Q000096:biosynthesis*; D011897:Random Allocation; D034561:Sheep, Domestic; D013997:Time Factors; D016896:Treatment Outcome; D015854:Up-Regulation / Q000502:physiology
chemical_list: D054439:Ghrelin; D009478:Neuropeptide Y