Orexins and feeding: special occasions or everyday occurrence?
Neurons expressing prepro-orexin, the precursor of orexin-A and -B, are found in the lateral hypothalamic area, a region classically implicated in driving feeding. Orexin-A induces feeding transiently when injected centrally, and food intake can be decreased when orexin action is disrupted by immunoneutralization of orexin-A, or by pharmacological blockade of orexin receptors, or by transgenic knockout of orexin. Here, we argue that orexin neurons may act to stimulate feeding in the short term, and that important regulatory signals may be a fall in plasma glucose (stimulatory), countered by satiety signals generated by eating, such as gastric distention (inhibitory).
Cai
Xue J
XJ
Department of Medicine, Diabetes and Endocrinology Research Group, University of Liverpool, L69 3GA, Liverpool, United Kingdom.
Liu
Xiao H
XH
Evans
Martyn
M
Clapham
John C
JC
Wilson
Shelagh
S
Arch
Jonathan R S
JR
Morris
Richard
R
Williams
Gareth
G
D000818:Animals; D001786:Blood Glucose / Q000502:physiology; D002352:Carrier Proteins / Q000096:biosynthesis / Q000502:physiology*; D004435:Eating / Q000502:physiology*; D006801:Humans; D006815:Hunger / Q000502:physiology; D007026:Hypothalamic Area, Lateral / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D020738:Leptin / Q000502:physiology; D009474:Neurons / Q000378:metabolism*; D009479:Neuropeptides / Q000096:biosynthesis / Q000502:physiology*; D000068797:Orexins; D012528:Satiety Response / Q000502:physiology
D001786:Blood Glucose; D002352:Carrier Proteins; C000596229:HCRT protein, human; D047908:Intracellular Signaling Peptides and Proteins; D020738:Leptin; D009479:Neuropeptides; D000068797:Orexins