Interstitial K(+) in human skeletal muscle during and after dynamic graded exercise determined by microdialysis.
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.
Juel
C
C
Copenhagen Muscle Research Centre, August Krogh Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark. cjuel@aki.ku.dk
Pilegaard
H
H
Nielsen
J J
JJ
Bangsbo
J
J
D000328:Adult; D004563:Electrochemistry; D015444:Exercise / Q000502:physiology*; D005110:Extracellular Space / Q000378:metabolism*; D006801:Humans; D007866:Leg; D008297:Male; D017551:Microdialysis; D018482:Muscle, Skeletal / Q000378:metabolism*; D010783:Photometry; D011188:Potassium / Q000378:metabolism*; D016059:Range of Motion, Articular
D011188:Potassium