An optimized method for measuring hypocretin-1 peptide in the mouse brain reveals differential circadian regulation of hypocretin-1 levels rostral and caudal to the hypothalamus.

Autor: Justinussen JL; Molecular Sleep Lab, Department of Clinical Biochemistry, Rigshospitalet, Glostrup, Denmark., Holm A; Molecular Sleep Lab, Department of Clinical Biochemistry, Rigshospitalet, Glostrup, Denmark., Kornum BR; Molecular Sleep Lab, Department of Clinical Biochemistry, Rigshospitalet, Glostrup, Denmark; Danish Center for Sleep Medicine, Department of Clinical Neurophysiology, Rigshospitalet, Glostrup, Denmark.
Jazyk: angličtina
Zdroj: Neuroscience [Neuroscience] 2015 Dec 03; Vol. 310, pp. 354-61. Date of Electronic Publication: 2015 Sep 28.
DOI: 10.1016/j.neuroscience.2015.09.050
Abstrakt: The hypocretin/orexin system regulates, among other things, sleep and energy homeostasis. The system is likely regulated by both homeostatic and circadian mechanisms. Little is known about local differences in the regulation of hypocretin activity. The aim of this study was to establish an optimized peptide quantification method for hypocretin-1 extracted from different mouse brain areas and use this method for investigating circadian fluctuations of hypocretin-1 levels in these areas. The results show that hypocretin-1 peptide can be extracted from small pieces of intact tissue, with sufficient yield for measurements in a standard radioimmunoassay. Utilizing the optimized method, it was found that prepro-hypocretin mRNA and peptide show circadian fluctuations in the mouse brain. This study further demonstrates that the hypocretin-1 peptide level in the frontal brain peaks during dark as does prepro-hypocretin mRNA in the hypothalamus. However, in midbrain and brainstem tissue caudal to the hypothalamus, there was less circadian fluctuation and a tendency for higher levels during the light phase. These data suggest that regulation of the hypocretin system differs between brain areas.
(Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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