title: Increased body weight in mice lacking mu-opioid receptors.
abstract: Opioids have been suggested to affect feeding behaviour. To clarify the role of mu-opioid receptors in feeding, we measured several parameters relating to food intake in mu-opioid receptor knockout mice. Here, we show that the knockout mice had increased body weight in adulthood, although the intake amount of standard food was similar between the wild-type and knockout littermates. Serum markers for energy homeostasis were not significantly altered in the knockout mice. Hypothalamic neuropeptide Y mRNA, however, was higher in knockouts than in wild-type mice. Our results suggest that the up-regulated expression of neuropeptide Y mRNA might contribute to the increased weights of adult mu-opioid receptor knockout mice.
authors.affiliation: Division of Psychobiology, Tokyo Institute of Psychiatry, Kamikitazawa, Tokyo, Japan.
authors.forename: Wenhua
authors.initials: W
authors.lastname: Han
authors.forename: Harumi
authors.initials: H
authors.lastname: Hata
authors.forename: Hiroki
authors.initials: H
authors.lastname: Imbe
authors.forename: Qing-Rong
authors.initials: QR
authors.lastname: Liu
authors.forename: Yukio
authors.initials: Y
authors.lastname: Takamatsu
authors.forename: Miwako
authors.initials: M
authors.lastname: Koizumi
authors.forename: Niall P
authors.initials: NP
authors.lastname: Murphy
authors.forename: Emiko
authors.initials: E
authors.lastname: Senba
authors.forename: George R
authors.initials: GR
authors.lastname: Uhl
authors.forename: Ichiro
authors.initials: I
authors.lastname: Sora
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Ikeda
mesh_terms: D045784:Abietanes / Q000097:blood; D000818:Animals; D001835:Body Weight / Q000235:genetics*; D004435:Eating / Q000235:genetics; D005951:Glucose Tolerance Test / Q000379:methods; D017403:In Situ Hybridization / Q000379:methods; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009478:Neuropeptide Y / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D017450:Receptors, Opioid, mu / Q000172:deficiency* / Q000502:physiology; D013997:Time Factors; D015854:Up-Regulation / Q000235:genetics
chemical_list: D045784:Abietanes; D009478:Neuropeptide Y; D012333:RNA, Messenger; D017450:Receptors, Opioid, mu; C045490:horminone