ABSTRACT
We used electrocardiogram (ECG) telemeters to measure the heart rate of hibernating Ictidomys tridecemlineatus (thirteen-lined ground squirrel). An increase in heart rate from 2.2 to 5 beats min–1 accurately identified arousal from torpor before any change in body temperature was detected. Variability in raw heart rate data was significantly reduced by a forward–backward Butterworth low-pass filter, allowing for discrete differential analysis. A decrease in filtered heart rate to 70% of maximum values in interbout euthermia (from approximately 312 to 235 beats min–1) accurately detected entrance into torpor bouts. At this point, body temperature had fallen from 36.1°C to only 34.7°C, much higher than the 30°C typically used to identify entrance. Using these heart rate criteria allowed advanced detection of entrance and arousal (detected 51.9 and 76 min earlier, respectively), compared with traditional body temperature criteria. This method will improve our ability to detect biochemical and molecular markers underlying these transition periods, during which many physiological changes occur.
FOOTNOTES
Competing interests
The authors declare no competing or financial interests.
Author contributions
Conceptualization: J.F.S.; Methodology: A.D.V.M., E.C.J., K.E.M., J.F.S.; Formal analysis: A.D.V.M., E.C.J., K.E.M.; Writing - original draft: A.D.V.M., E.C.J., K.E.M., J.F.S.; Writing - review & editing: A.D.V.M., E.C.J., K.E.M., J.F.S.; Supervision: J.F.S.; Funding acquisition: J.F.S.
Funding
This research was supported by a Discovery Grant from the Natural Sciences and Engineering Research Council of Canada (RGPIN-2014-04860) and the Faculty of Science, University of Western Ontario (Western University; grant number R3061A08).
Supplementary information
Supplementary information available online at http://jeb.biologists.org/lookup/doi/10.1242/jeb.174508.supplemental
- Received November 16, 2017.
- Accepted January 10, 2018.
- © 2018. Published by The Company of Biologists Ltd
Article navigation
Related articles
Cited by...
More in this TOC section
Similar articles
Other journals from The Company of Biologists
JEB and COVID-19
We are aware that the COVID-19 pandemic is having an unprecedented impact on researchers worldwide. The Editors of all The Company of Biologists’ journals have been considering ways in which we can alleviate concerns that members of our community may have around publishing activities during this time. Read about the actions we are taking at this time.
Please don’t hesitate to contact the Editorial Office if you have any questions or concerns.
Announcing JEB's 2019 Outstanding Paper Prize
Congratulations to all of the authors whose papers were shortlisted for the 2019 JEB Outstanding Paper Prize. This year we had a great selection of papers and the final winners were Kephra Beckett and Anne Roberts, from the University of British Columbia, Canada, for their work on spittlebug breathing in xylem sap foam.
The Biology Open transfer option
JEB authors have the option to transfer their submission to our sister journal Biology Open. An online Open Access journal, BiO also welcomes direct submissions and focuses on the swift publication of high-quality, sound research. Recent comparative physiology highlights in BiO include the current cover article from Okuyama et al., who show that Green sea turtles have an immediate cardiac response to exercise during submergence. Find out more about how to transfer.
Mantis shrimp pull punches in air for self-preservation
In their new Short Communication, Feller et al. demonstrate that punches by mantis shrimp in air are slower and only one tenth of the power than in thick water.
What determines systemic blood flow in vertebrates?
To understand how systemic blood flow is regulated, Tobias Wang and William Joyce look at factors beyond the heart in their new Review.
JEB appoints new Editor-in-Chief
We are delighted to announce that Craig Franklin (University of Queensland, Australia) has been appointed as the next EiC of JEB, starting on 1 August. With research interests in animal ecophysiology and conservation physiology, Craig is already familiar with the journal, having been a Monitoring Editor since 2011. We are looking forward to welcoming him in his new role.