目的：探讨在低氧性脑损伤发生过程中，Ｎａ＋Ｃａ２＋ 交换体在细胞内钙超载中的作用。方法：采用全细胞膜片钳方法，在急性分离海马神经元上观察低氧对Ｎａ＋Ｃａ２＋ 交换电流的电流电压（ＩＶ） 曲线的影响。结果：在整个膜电位水平，Ｎａ＋Ｃａ２＋ 交换电流幅值均不同程度的增加，在正膜电位水平呈现一显著的外向电流。１０ ｍＶ 时，电流幅值从（９２ ．８３ ±２０．８）ｐＡ上升到（１３０ ．６７ ±２６．８８）ｐＡ（ Ｐ＜０ ．０５） ，而在５０ ｍ Ｖ，其电流幅值从（－ ７４ ．６７ ±１１ ．８４）ｐＡ上升到（－ ５８ ．５±１０ ．７１）ｐＡ（Ｐ＜ ０ ．０５）。结论：低氧时Ｎａ＋Ｃａ２＋ 交换电流呈外向性，这种改变有利于低氧后通过Ｎａ＋Ｃａ２＋ 交换的外向转运方式排出细胞内钠，并交换钙进入细胞 Objective: To investigate the role of Na + Ca2 + exchanger in intracellular calcium overload in the process of hypoxic brain injury. Methods: Whole-cell patch-clamp method was used to observe the effect of hypoxia on the current-voltage curve of Na + -Ca2 + exchange current in acutely isolated hippocampal neurons. Results: The amplitudes of Na + Ca2 + exchange current all increased to some extent at the whole membrane potential level, showing a significant outward current at the positive membrane potential. At 10 mV, the current amplitude increased from (92.83 ± 20.8) pA to (130.67 ± 26.88) pA (P <0.05), while at 50 mV, the current amplitude increased from (-74.67 ± 11.84) pA increased to (-58.5 ± 10.71) pA (P <0.05). CONCLUSION: The exogenous Na + -Ca2 + current during hypoxia is extrinsic, which is beneficial to the excretion of intracellular Na by exogeneous transport via Na + Ca2 + exchange after hypoxia, and the exchange of calcium into cells