Hallén J, Sejersted O M
Department of Physiology, National Institute of Occupational Health, Oslo, Norway.
J Appl Physiol (1985). 1993 Nov;75(5):2318-25. doi: 10.1152/jappl.1993.75.5.2318.
Continuous recording of plasma K+ concentration ([K+]) during exercise would be valuable in determining K+ fluxes associated with muscle activation. Pliable polyvinyl chloride electrodes were constructed by incorporation of valinomycin into a polyvinyl chloride membrane attached to the end of a catheter with a 1 mm outer diameter. Through an outer catheter the electrode was inserted into the femoral vein of human subjects. The setup allowed easy in vivo calibration, and rapid changes of femoral venous [K+] of < 0.1 mmol/l could easily be detected. Drift over 1 h amounted to < 3 mV and was corrected for by analysis of blood samples. Rapid changes in femoral venous [K+] occurred during and after dynamic exercise, short and prolonged isometric contractions, and repetitive isometric contractions of the quadriceps muscle. Combined with arterial blood sampling and flow measurements, the electrodes will allow good approximation of 1) cellular K+ efflux rate associated with increased electrical activity, 2) rate of intramuscular reuptake of K+ mediated by the Na(+)-K+ pump, and 3) rate of K+ loss to or uptake from the circulation by the muscle.
运动期间连续记录血浆钾离子浓度（[K⁺]）对于确定与肌肉激活相关的钾离子通量具有重要价值。通过将缬氨霉素掺入附着于外径为1毫米的导管末端的聚氯乙烯膜中，构建了柔韧的聚氯乙烯电极。通过外部导管将电极插入人体受试者的股静脉。该装置便于进行体内校准，并且能够轻松检测到股静脉[K⁺]小于0.1 mmol/l的快速变化。1小时内的漂移量小于3 mV，可通过分析血样进行校正。在动态运动期间和之后、短时间和长时间等长收缩以及股四头肌的重复等长收缩过程中，股静脉[K⁺]会发生快速变化。结合动脉血采样和流量测量，这些电极将有助于很好地估算：1）与电活动增加相关的细胞钾离子外流速率；2）由钠钾泵介导的肌肉内钾离子再摄取速率；3）肌肉向循环系统丢失或从循环系统摄取钾离子的速率。
