Interstitial K+ in human skeletal muscle during and after dynamic graded exercise determined by microdialysis

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Interstitial K+ concentrations were measured during one-legged knee- extensor exercise by use of microdialysis with probes inserted in the vastus lateralis muscle of the subjects. K+ in the dialysate was measured either by flame photometry or a K+-sensitive electrode placed in the perfusion outlet. The correction for fractional K+ recovery was based on the assumption of identical fractional thallium loss. The interstitial K+ was 4.19 ± 0.09 mM at rest and increased to 6.17 ± 0.19, 7.48 ± 1.18, and 9.04 ± 0.74 mM at 10, 30, and 50 W exercise, respectively. The individual probes demonstrated large variations in interstitial K+, and values >10 mM were obtained. The observed interstitial K+, was markedly higher than previously found for venous K+, concentrations at similar work intensities. The present data support a potential role for interstitial K+, in regulation of blood flow and development of fatigue.

OriginalsprogEngelsk
TidsskriftAmerican Journal of Physiology: Regulatory, Integrative and Comparative Physiology
Vol/bind278
Udgave nummer2
Sider (fra-til)R400-R406
Antal sider7
ISSN0363-6119
StatusUdgivet - 2000

ID: 210151349