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产电性Na-Ca 交换是心肌细胞膜排Ca~(2+)的重要机制,其交换率为3 Na∶/Ca。日本Kimura 用细胞灌流和全细胞电压钳制术,首次直接记录到外向Na-Ca 交换电流。用宽斜面玻璃管(直径4～5μm,阻抗1～2MΩ)将溶液注入豚鼠心室肌细胞。配制的浸浴液和管溶液可阻断大多数通道电流和产电性Na-K 泵,以减少时间依赖性电流成分,使电流-电压(I-V)近乎为直线关系。实验先用不含Na~+的胞内溶液和不含游离Ca~(2+)的胞外溶液灌流,再灌流1 mmol/L Ca~(2+),外向膜电
Electrogenic Na-Ca exchange is an important mechanism of myocardial cell membrane Ca 2+ release, and its exchange rate is 3 Na: / Ca. Japan Kimura with cell perfusion and whole-cell voltage clamp technique, the first direct export to export Na-Ca exchange current. The solution was injected into guinea pig ventricular myocytes with a wide beveled glass tube (4 to 5 μm in diameter and 1 to 2 M impedance). The prepared immersion bath and tube solutions block the majority of the channel currents and electrokinetic Na-K pumps to reduce the time-dependent current components, resulting in a nearly linear current-voltage (I-V) relationship. The experiment first perfusion with intracellular solution without Na ~ + and extracellular solution without free Ca ~ (2+), reperfusion 1 mmol / L Ca ~ (2+), extrinsic membrane