Journal article
Spontaneous sleep and homeostatic sleep regulation in ghrelin knockout mice
American journal of physiology. Regulatory, integrative and comparative physiology, Vol.293(1), pp.R510-517
07/2007
Handle:
https://hdl.handle.net/2376/117450
PMID: 17409264
Abstract
Ghrelin is well known for its feeding and growth hormone-releasing actions. It may also be involved in sleep regulation; intracerebroventricular administration and hypothalamic microinjections of ghrelin stimulate wakefulness in rats. Hypothalamic ghrelin, together with neuropeptide Y and orexin form a food intake-regulatory circuit. We hypothesized that this circuit also promotes arousal. To further investigate the role of ghrelin in the regulation of sleep-wakefulness, we characterized spontaneous and homeostatic sleep regulation in ghrelin knockout (KO) and wild-type (WT) mice. Both groups of mice exhibited similar diurnal rhythms with more sleep and less wakefulness during the light period. In ghrelin KO mice, spontaneous wakefulness and rapid-eye-movement sleep (REMS) were slightly elevated, and non-rapid-eye-movement sleep (NREMS) was reduced. KO mice had more fragmented NREMS than WT mice, as indicated by the shorter and greater number of NREMS episodes. Six hours of sleep deprivation induced rebound increases in NREMS and REMS and biphasic changes in electroencephalographic slow-wave activity (EEG SWA) in both genotypes. Ghrelin KO mice recovered from NREMS and REMS loss faster, and the delayed reduction in EEG SWA, occurring after sleep loss-enhanced increases in EEG SWA, was shorter-lasting compared with WT mice. These findings suggest that the basic sleep-wake regulatory mechanisms in ghrelin KO mice are not impaired and they are able to mount adequate rebound sleep in response to a homeostatic challenge. It is possible that redundancy in the arousal systems of the brain or activation of compensatory mechanisms during development allow for normal sleep-wake regulation in ghrelin KO mice.
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Details
- Title
- Spontaneous sleep and homeostatic sleep regulation in ghrelin knockout mice
- Creators
- Eva Szentirmai - Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, Program in Neuroscience, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-6520, USALevente KapásYuxiang SunRoy G SmithJames M Krueger
- Publication Details
- American journal of physiology. Regulatory, integrative and comparative physiology, Vol.293(1), pp.R510-517
- Academic Unit
- Biomedical Sciences, Department of; Integrative Physiology and Neuroscience, Department of
- Publisher
- United States
- Grant note
- R01 AG 1923 / NIA NIH HHS NS 27250 / NINDS NIH HHS R01 AG 18895 / NIA NIH HHS
- Identifiers
- 99900548462301842
- Language
- English
- Resource Type
- Journal article