Carrasquer G, Ahn S, Schwartz M, Rehm W S
Am J Physiol. 1985 Aug;249(2 Pt 2):F185-91. doi: 10.1152/ajprenal.1985.249.2.F185.
The effect of changing the K concentration in the aqueous solution was studied in the frog cornea. In general, when the K concentration was increased from 4 to 20 or 79 mM, the transepithelial PD and resistance decreased. If K was decreased from 79 to 4, 20 to 4, or 4 to 0 mM, or any other combination, the PD and resistance increased. These are normal PD responses. If after a K-free period of more than 5-10 min the K was increased to 4 mM, the PD increased, an anomalous PD response. If K was increased from 0 to 20 mM, there was an initial PD increase (anomalous response) followed by a PD decrease (normal response). If K was increased from 0 to 79 mM the PD decreased, normal response only. The resistance decreased with every increase in K concentration. Anomalous responses were abolished in Na-free solutions and in the presence of both 10(-3) M ouabain and 10(-4) M vanadate in the aqueous solution. We interpret the results on the basis of two pathways, a simple K-conductive pathway and an electrogenic Na-K-ATPase pump pathway with more Na's than K's per cycle. The normal or anomalous PD responses to changes in aqueous K concentration depend on the relative resistance of the two pathways.
在蛙角膜中研究了改变水溶液中钾离子浓度的影响。一般来说，当钾离子浓度从4 mM增加到20 mM或79 mM时，跨上皮电位差（PD）和电阻会降低。如果钾离子浓度从79 mM降至4 mM、从20 mM降至4 mM、从4 mM降至0 mM或任何其他组合，PD和电阻则会增加。这些都是正常的PD反应。如果在无钾离子环境中超过5 - 10分钟后，将钾离子浓度增加到4 mM，PD会增加，这是一种异常的PD反应。如果钾离子浓度从0 mM增加到20 mM，最初PD会增加（异常反应），随后PD会降低（正常反应）。如果钾离子浓度从0 mM增加到79 mM，PD会降低，仅为正常反应。随着钾离子浓度的每次增加，电阻都会降低。在无钠溶液以及水溶液中同时存在10⁻³ M哇巴因和10⁻⁴ M钒酸盐时，异常反应会消失。我们基于两条途径来解释这些结果，一条是简单的钾离子传导途径，另一条是每循环转运的钠离子比钾离子更多的电生性钠钾ATP酶泵途径。对水溶液中钾离子浓度变化的正常或异常PD反应取决于这两条途径的相对电阻。
