Orexin A immunoreactivity and preproorexin mRNA in the brain of Zucker and WKY rats.
The primary role of the orexins was originally believed to be appetite regulation, but is now believed to be the regulation of sleep, arousal and locomotor activity. Orexin A immunoreactivity (orexin A-IR) and prepro-orexin mRNA were measured in the CNS of obese and lean Zucker rats. There were no differences in orexin A-IR or prepro-orexin mRNA levels between obese and lean Zucker rats. The orexins are therefore unlikely to be important in this model of obesity. Levels of orexin A-IR and prepro-orexin mRNA were measured in the CNS of Wistar-Kyoto (WKY) rats, which are hypoactive and have abnormal sleep architecture. Compared to Wistar rats, WKY rats had significantly lower orexin A-IR (with differences of up to 100% in some brain regions) and prepro-orexin mRNA levels. These observations suggest that the sleep and activity phenotype of the WKY strain may be related to orexin deficiency and that this strain may be a useful model of partial orexin deficiency.
Endocrine Unit, Division of Investigative Sciences, Imperial College School of Medicine, The Hammersmith Hospital, London, UK.
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Taheri
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Gardiner
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Hafizi
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Murphy
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Dakin
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Seal
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Small
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Ghatei
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Bloom
D000818:Animals; D000906:Antibodies; D001923:Brain Chemistry / Q000502:physiology*; D002352:Carrier Proteins / Q000032:analysis* / Q000276:immunology; D004195:Disease Models, Animal; D015870:Gene Expression / Q000502:physiology; D007031:Hypothalamus / Q000737:chemistry / Q000502:physiology; D047908:Intracellular Signaling Peptides and Proteins; D008124:Locomotion; D008297:Male; D009478:Neuropeptide Y / Q000032:analysis / Q000276:immunology; D009479:Neuropeptides / Q000032:analysis* / Q000172:deficiency / Q000276:immunology; D009765:Obesity / Q000503:physiopathology; D000068797:Orexins; D011498:Protein Precursors / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D011921:Rats, Inbred WKY; D017208:Rats, Wistar; D011924:Rats, Zucker; D012890:Sleep; D013045:Species Specificity
D000906:Antibodies; D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009478:Neuropeptide Y; D009479:Neuropeptides; D000068797:Orexins; D011498:Protein Precursors; D012333:RNA, Messenger