Effect of intermittent high-frequency stimulation on muscle velocity recovery cycle recordings.

Hochstrasser, Annie; Rodriguez, Belén; Söll, Nicole; Bostock, Hugh; Z'Graggen, Werner J. (2021). Effect of intermittent high-frequency stimulation on muscle velocity recovery cycle recordings. Journal of neurophysiology, 126(3), pp. 736-742. American Physiological Society 10.1152/jn.00213.2021

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The technique of multifiber muscle velocity recovery cycle recordings was developed as a diagnostic tool to assess muscle membrane potential changes and ion channel function in vivo. This study was undertaken to assess the impact of intermittent high-frequency stimulation on muscle velocity recovery cycle components and to study whether the changes can be modified by endurance training. We recorded muscle velocity recovery cycles with 1 and 2 conditioning stimuli in the left tibialis anterior muscle in 15 healthy subjects during intermittent 37-Hz stimulation and analyzed its effects on the different phases of supernormality. Recordings were conducted before and after 2-wk endurance training. Training effect was assessed by measuring the difference in endurance time, peak force, and limb circumference. Muscle velocity recovery cycle recordings during intermittent high-frequency stimulation were successfully recorded in 12 subjects. Supernormality for interstimulus intervals shorter than 15 ms (early supernormality) was maximally reduced at the beginning of repetitive stimulation and recovered during stimulation. Supernormality for interstimulus intervals between 50 and 150 ms (late supernormality) showed a delayed decrease and stayed significantly reduced after high-frequency stimulation. Training had no significant effect on any of the measured parameters, but we found that training induced changes in peak force correlated positively with baseline changes of early supernormality. Our results support the hypothesis that early supernormality represents membrane potential, which depolarizes in the beginning of high-frequency stimulation. Late supernormality probably reflects transverse tubular function and shows progressive changes during high-frequency stimulation with delayed normalization.NEW & NOTEWORTHY A conditioning impulse in human muscle fibers induces a prolonged phase of increased velocity (also called supernormality) with two phases related to an early and late afterpotential. We investigated the effects of intermittent 37-Hz stimulation on muscle fiber supernormality and found that the early and late phases of supernormality changed differently, and that the late phase may reflect the ionic interactions responsible for the counter-regulation of muscle fatigue.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Department of Head Organs and Neurology (DKNS) > Clinic of Neurology
04 Faculty of Medicine > Department of Head Organs and Neurology (DKNS) > Clinic of Neurosurgery

UniBE Contributor:

Rodriguez Galdin, Belén, Soell, Nicole, Z'Graggen, Werner Josef

Subjects:

600 Technology > 610 Medicine & health
100 Philosophy > 150 Psychology

ISSN:

0022-3077

Publisher:

American Physiological Society

Language:

English

Submitter:

Nicole Söll

Date Deposited:

08 Nov 2021 09:04

Last Modified:

05 Dec 2022 15:53

Publisher DOI:

10.1152/jn.00213.2021

PubMed ID:

34288792

Uncontrolled Keywords:

endurance training fatigue muscle membrane potential supernormality transverse tubules

BORIS DOI:

10.48350/159942

URI:

https://boris.unibe.ch/id/eprint/159942

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