Abstract
At the annual Iditarod Race, Alaskan Huskies repeatedly run for up to 8 hours at 16 km/h to complete 1600 km. We previously demonstrated high rates of mitochondrial protein synthesis in Alaskan Huskies, which we suspected allowed rapid remodeling of mitochondrial proteins in response to energetic stress. The purpose of this study was to examine mitochondrial respiration in permeabilized skeletal muscle fibers of Alaskan Huskies in the offseason (Non-raced) and following the 1600 km Iditarod Sled Dog Race (Raced). We hypothesized that compared to Non-raced Huskies, raced Huskies that completed a 1600 km race would have greater mitochondrial respiratory capacities, and improvements in capacities of oxidative phosphorylation (OXPHOS) based on NADH-generating substrates as compared to fatty acids. Using high-resolution respirometry (HRR) we investigated the respiration of permeabilized muscle fibers from Alaskan Huskies. Maximum capacities were 254±26 pmol.s-1.mg-1 for OXPHOS (coupled, P) and 254±37 pmol.s-1.mg-1 for the electron transfer system (ETS; non-coupled, E). After racing respiratory capacities from NADH-linked substrates, but not fat-derived substrates increased. Finally, the OXPHOS to ETS capacity ratio (P/E) increased after racing from 0.90±0.03 to 0.97±0.02. From our previous studies and the current study, we conclude that Alaskan Huskies maintain high mitochondrial protein turnover to facilitate rapid adaptation to environmental extremes and energetic challenges.
Highlights
At the annual Iditarod Race, winning sled dog teams can cover 1600 km in less than nine days
Addition of ADP to achieve oxidative phosphorylation (OXPHOS) capacity with fatty acid substrate (FAOP) resulted in FAOP that was lower in Raced (59±19) compared to Non-raced (83±6 pmol.s-1.mg-1) dogs (p = 0.01)
Uncoupling of the respiratory system with subsequent titration of Carbonyl cyanide m-chloro phenyl hydrazone (CCCP) (CI&CII&fatty acid oxidation (FAO))E increased oxygen flux above coupled respiration in both the Raced (253±26) and Non-raced (254±42, pmol.s-1.mg-1) dogs (p = 0.49), as reflected in the P/E ratio that was higher in Raced (0.97±0.02) compared to Non-raced (0.90±0.03) (p < 0.005) (Fig 3)
Summary
At the annual Iditarod Race, winning sled dog teams can cover 1600 km in less than nine days. The dogs repeatedly complete runs of up to 8 hours at 16 km/h. Instruments provided salary and travel funds for these authors, as well as several “loaner” instruments that were used in addition to instruments owned by other authors for sample analysis, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
