Role of rat vascular KATP channels in setting microvascular oxygen pressure at the onset of contractions

Authors

Clark Holdsworth¹ , Scott Ferguson¹ , Jennifer Wright¹ , Alexander Fees¹ , Timothy Musch¹ , David Poole¹

1. Kansas State University

Conference / event

Experimental Biology, April 2014 (San Diego, CA, United States)

Poster summary

Vascular hyperpolarization mediated, in part, by the ATP-sensitive K+ (KATP) channel contributes to exercise-induced increases in skeletal muscle O2 delivery. We hypothesized that KATP channel inhibition via glibenclamide (GLI) would speed the fall of microvascular O2 driving pressure (PO2mv; set by the O2 delivery-O2 utilization ratio), following the onset of muscle contractions. Spinotrapezius PO2mv (phosphorescence quenching) was measured in 12 adult Sprague Dawley rats during 180 s of 1-Hz twitch contractions (~7 V) under control and GLI (5 mg/kg) conditions. Following the onset of contractions the total mean response time was greater with GLI (control: 42.0 ± 14.2, GLI: 79.5 ± 14.7 s). A clear undershoot of the contracting steady-state PO2mv was evident with GLI (15.6 ± 5.3 %) but not control (2.3 ± 1.6 %). This indicates that KATP channel inhibition does not speed PO2mv kinetics during small muscle mass electrical stimulation, but causes a transient mismatch of O2 delivery-O2 utilization prior to stabilizing at the contracting steady-state.

Keywords

microcirculation, oxygen diffusion, vascular control, metabolic coupling

Research areas

Anatomy and Physiology

References

No data provided

Funding

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Supplemental files

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Additional information

Competing interests

No competing interests were disclosed.

Data availability statement

The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.

Creative Commons license

Copyright © 2022 Holdsworth et al. This is an open access work distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.