UMMS Affiliation

Department of Neurobiology; Weaver Lab

Publication Date

2018-06-14

Document Type

Article Postprint

Disciplines

Neuroscience and Neurobiology

Abstract

Daily torpor is used by small mammals to reduce daily energy expenditure in response to energetic challenges. Optimizing the timing of daily torpor allows mammals to maximize its energetic benefits and, accordingly, torpor typically occurs in the late night and early morning in most species. The regulatory mechanisms underlying such temporal regulation have however not been elucidated. Direct control by the circadian clock and indirect control through the timing of food intake have both been suggested as possible mechanisms. Here, feeding cycles outside of the circadian range and brain-specific mutations of circadian clock genes (Vgat-Cre(+)CK1delta(fl/fl)(fl/+); Vgat-Cre(+)Bmal1(fl/fl) ) were used to separate the roles of the circadian clock and food timing in controlling the timing of daily torpor in mice. These experiments revealed that the timing of daily torpor is transiently inhibited by feeding, while the circadian clock is the major determinant of the timing of torpor. Torpor never occurred during the early part of the circadian active phase, but is preferentially initiated late in the subjective night. Food intake disrupted torpor in the first 4-6 h after feeding by preventing or interrupting torpor bouts. Following interruption, re-initiation of torpor was unlikely until after the next circadian active phase. Overall, these results demonstrate that feeding transiently inhibits torpor while the central circadian clock gates the timing of daily torpor in response to energetic challenges by restricting the initiation of torpor to a specific circadian phase.

Keywords

Body temperature, Circadian rhythm, Clock mutant, Energetic savings, Metabolism, Suprachiasmatic nucleus

Rights and Permissions

© 2018. Published by The Company of Biologists Ltd. Accepted manuscript posted after 12 months as allowed by the publisher's license at http://www.biologists.com/user-licence-1-1/.

DOI of Published Version

10.1242/jeb.179812

Source

J Exp Biol. 2018 Jun 14. pii: jeb.179812. doi: 10.1242/jeb.179812. [Epub ahead of print] Link to article on publisher's site

Journal/Book/Conference Title

The Journal of experimental biology

Related Resources

Link to Article in PubMed

PubMed ID

29903839

Available for download on Friday, June 14, 2019

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