Bridge J H, Bassingthwaighte J B
Science. 1983 Jan 14;219(4581):178-80. doi: 10.1126/science.6849128.
Heart cells were loaded with sodium by treatment with toxic doses of acetyl strophanthidin. After this treatment, an increase in extracellular calcium resulted in a transient net outward sodium flux against its electrochemical gradient and in net cellular uptake of calcium. It is concluded that the free energy for the net outward sodium movement was derived from the increased calcium gradient and that these ion movements took place through the sodium-calcium exchange. While in the normal physiological state the sodium-calcium exchange produces calcium extrusion from the cell, these experiments demonstrate its reversibility.
通过用毒性剂量的乙酰毒毛旋花子苷处理，使心脏细胞内充满钠。经过这种处理后，细胞外钙的增加导致钠逆其电化学梯度出现短暂的净外向通量，并使细胞净摄取钙。得出的结论是，钠净外向移动的自由能来自增加的钙梯度，并且这些离子移动是通过钠钙交换发生的。虽然在正常生理状态下钠钙交换使钙从细胞中排出，但这些实验证明了其可逆性。
