Increased body weight in mice lacking mu-opioid receptors.
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.
Han
Wenhua
W
Division of Psychobiology, Tokyo Institute of Psychiatry, Kamikitazawa, Tokyo, Japan.
Hata
Harumi
H
Imbe
Hiroki
H
Liu
Qing-Rong
QR
Takamatsu
Yukio
Y
Koizumi
Miwako
M
Murphy
Niall P
NP
Senba
Emiko
E
Uhl
George R
GR
Sora
Ichiro
I
Ikeda
Kazutaka
K
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
D045784:Abietanes; D009478:Neuropeptide Y; D012333:RNA, Messenger; D017450:Receptors, Opioid, mu; C045490:horminone