Document Type
Article
Publication Date
October 2019
Publication Title
Physiological Reports
Volume
7
Issue Number
20
DOI
10.14814/phy2.14271
Keywords
Diet‐induced obesity, electrophysiology, Hoffmann’s reflex, rate dependent depression
Disciplines
Biology | Life Sciences
Abstract
Obesity is associated with balance and motor control deficits. We have recently shown that Group Ia muscle spindle afferents, the sensory arm of the muscle stretch reflex, are less responsive in mice fed a high-fat diet. Here we test the hypothesis that reflex excitability to sensory information from Group Ia muscle spindle afferents is altered in a mouse model of diet-induced obesity. We measured the anesthetized Hoffmann’s or H-reflex, the electrical analog of the muscle stretch reflex. Adult mice of both sexes were fed a control diet (CD; 10% kcal from fat) or a high-fat diet (HFD; 60% kcal from fat) for 5, 10, or 15 weeks. We used three quantitative measures of H-reflex excitability: (1) H-reflex latency; (2) the percentage of motor neurons recruited from electrical stimulation of Group Ia muscle spindle afferents (Hmax/Mmax); and (3) rate-dependent depression (RDD), the decrease in H-reflex amplitude to high frequency stimulation (20 stimuli at 5 Hz). A HFD did not significantly alter H latency (P = 0.16) or Hmax/Mmax ratios (P = 0.06), but RDD was significantly lower in HFD compared to CD groups (P < 0.001). Interestingly, HFD males exhibited decreased RDD compared to controls only after 5 and 10 weeks of feeding, but females showed progressive decreases in RDD that were only significant at 10 and 15 weeks on the HFD. These results suggest that high-fat feeding increases H-reflex excitability. Future studies are needed to determine whether these changes alter muscle stretch reflex strength and/or balance and to determine the underlying mechanism(s).
Recommended Citation
Gerard Nguyen, Shea Putnam, Mulatwa Haile, Zahra Raza, Martina Bremer, and Katherine Wilkinson. "Diet‐induced obesity decreases rate‐dependent depression in the Hoffmann’s reflex in adult mice" Physiological Reports (2019). https://doi.org/10.14814/phy2.14271
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Comments
© 2019 The Authors. This article appears in Physiological Reports, volume 7, issue 20, 2019, published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society. The article can be found online by following this link: https://doi.org/10.14814/phy2.14271
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.