Zhang L, Weiner J L, Valiante T A, Velumian A A, Watson P L, Jahromi S S, Schertzer S, Pennefather P, Carlen P L
Playfair Neuroscience Unit, Bloorview Epilepsy Research Program, Toronto Hospital Research Institute, Toronto Hospital, Ontario, Canada.
Pflugers Arch. 1994 Feb;426(3-4):247-53. doi: 10.1007/BF00374778.
Using the whole-cell recording technique, we have examined the slow Ca(2+)-activated afterhyperpolarization (AHP) and its underlying current (IAHP) in hippocampal CA1 neurones of brain slices obtained from mature rats. Specifically we have studied the effects of the anion component of various K+ salts commonly used to make the pipette filling solution that dialyses neurones during whole-cell recordings. Among the K+ salts examined which included potassium methylsulfate, potassium methanesulfonate, potassium gluconate, potassium chloride, potassium citrate and potassium glutamate, stable AHPs/IAHP and strong spike firing adaptation could only be observed in neurones recorded with the patch pipette solution containing potassium methylsulfate. These AHPs and firing patterns closely mimicked those recorded with sharp electrodes. Similarly, the sustained component of voltage-activated Ca2+ currents was more stable in neurones dialysed with cesium methanesulfonate than in those dialysed with cesium gluconate or cesium chloride. Although the mechanisms underlying the interaction(s) between internally applied anions and ionic channels need further investigation, the present experiments illustrate that in mammalian brain neurones at 33 degrees C, the Ca(2+)-activated IAHP is dramatically altered by internal anions. We suggest that among anions commonly used in electrode filling solutions for whole-cell recordings, methylsulfate is the least disruptive to intracellular structures or Ca2+ homeostasis and permits stable whole-cell recording of the IAHP and Ca2+ currents in mammalian CNS neurones.
运用全细胞记录技术，我们研究了从成年大鼠获取的脑片海马CA1神经元中的缓慢钙激活后超极化（AHP）及其潜在电流（IAHP）。具体而言，我们研究了全细胞记录过程中用于制备透析神经元的移液管填充溶液的各种钾盐的阴离子成分的影响。在所研究的钾盐中，包括硫酸甲酯钾、甲磺酸钾、葡萄糖酸钾、氯化钾、柠檬酸钾和谷氨酸钾，只有在用含有硫酸甲酯钾的膜片移液管溶液记录的神经元中才能观察到稳定的AHP/IAHP和强烈的动作电位发放适应。这些AHP和发放模式与用尖锐电极记录的非常相似。同样，用甲磺酸铯透析的神经元中电压激活钙电流的持续成分比用葡萄糖酸铯或氯化铯透析的神经元更稳定。尽管细胞内应用的阴离子与离子通道之间相互作用的潜在机制需要进一步研究，但目前的实验表明，在33℃的哺乳动物脑神经元中，钙激活的IAHP会因细胞内阴离子而发生显著改变。我们认为，在全细胞记录电极填充溶液中常用的阴离子中，硫酸甲酯对细胞内结构或钙稳态的干扰最小，并能在哺乳动物中枢神经系统神经元中稳定地进行IAHP和钙电流的全细胞记录。
