Noack E, Dransfeld H
Arzneimittelforschung. 1976;26(8):1538-42.
The conditions of potassium transport were investigated in isolated rabbit hear mitochondria. In the presence of 5 to 40 mM potassium chloride there is a rapid initial phase of potassium influx of less than 2 min duration in which 65-75% of the total K+ uptake occurs. This is followed by a slow phase of K+ uptake of about 45 min during which 25 to 35% of the total potassium was taken up. While the rapid phase is due to passive diffusion, the slow phase is an active process which requires either ATP or respiratory substrates as an energy source. It can be totally abolished by 0.5 mM antimycin A. An increase of the calcium concentration in the incubation medium to more than 5 X 10(-5)M resulted in an inhibition of the energy-dependent uptake of potassium which was directly proportional to the calcium level. k-Strophanthin induced a distinct inhibition only at very high concentration (greater than 10(-4)M). The inhibition of potassium uptake by 1. 3 or 5 mM calcium chloride was gradually cancelled by increasing k-strophanthin concentrations above 10(-8)M. Maximal cancellation was found with 10(-5)M of k-strophanthin. This concentration almost completely prevented the inhibition by calcium ions. On the other hand, 10(-5)M k-strophanthin had no inhibitory effect on the energy-dependent uptake of 0.5 mumoles of calcium chloride or on the oxidative phosphorylation of 0.5 mumoles of ADP added to the incubation medium.
在离体兔心脏线粒体中研究了钾转运的条件。在存在5至40mM氯化钾的情况下，钾流入有一个快速的初始阶段，持续时间不到2分钟，在此期间发生的钾总摄取量的65 - 75%。随后是一个约45分钟的钾摄取缓慢阶段，在此期间摄取了总钾量的25%至35%。快速阶段是由于被动扩散，而缓慢阶段是一个活跃过程，需要ATP或呼吸底物作为能量来源。它可被0.5mM抗霉素A完全消除。将孵育培养基中的钙浓度增加到超过5×10(-5)M会导致对能量依赖性钾摄取的抑制，这种抑制与钙水平成正比。毒毛花苷仅在非常高的浓度（大于10(-4)M）时才引起明显的抑制。通过将毒毛花苷浓度增加到高于10(-8)M，1.3或5mM氯化钙对钾摄取的抑制作用逐渐被消除。在毒毛花苷浓度为10(-5)M时发现最大消除。该浓度几乎完全阻止了钙离子的抑制作用。另一方面，10(-5)M毒毛花苷对0.5微摩尔氯化钙的能量依赖性摄取或添加到孵育培养基中的0.5微摩尔ADP的氧化磷酸化没有抑制作用。
