蟾蜍背根神经节胞体动作电位离子成份的分析

An Analysis of the Ionic Components of the Action Potential in Toad Dorsal Root Ganglion

在蟾蜍离体背根神经节标本上，用标准微电极方法，通过改变胞外离子成份及浓度，结合应用离子通道阻滞剂，分析胞体动作电位各离子成份。结果表明：５μｍｏｌ／Ｌ河豚毒灌流６ｍｉｎ后，动作电位幅值及去极相斜率均明显减小；无Ｃａ（２＋）（０ｍｍｏｌ／Ｌ）和高Ｃａ（２＋）（１０、２０ｍｍｏｌ／Ｌ）液灌流１５ｍｉｎ后，动作电位时程（ＡＰＤ）分别较对照值减小和增大；无Ｋ＋（Ｏｍｍｏｌ／Ｌ）和高Ｋ＋（６ｍｍｏｌ／Ｌ）液灌流１５ｍｉｎ后，ＡＰＤ的改变与上述相同；２ｍｍｏｌ／ＬＭｎ（２＋）和１０ｍｍｏｌ／Ｌ四乙胺亦可分别使ＡＰＤ较对照值减小和增大。实验表明胞外Ｃａ（２＋）的改变与ＡＰＤ值的大小呈线性关系。

Analysis of the ionic components of the action potential(AP)which was recorded intracellularly from isolated toad dorsal root ganglion (DRG )was carried out by means of changing the ionic concentration in perfusate and administering blocking agents for ionic channels. It was shown that both the amplitude and the rate of rise in the rising phase of AP decreased respectively during perfusion of 5μmol/L TTX for 6 minutes. During perfusion of low(0 mmol/L)and high(10, 20 mmol/L)Ca￣(2+)Ringers solution,a decrease and an increase in APD value occurred respectively. The same results were obtained while the preparation was perfused with low(0 mmol/L) and high(6 mmol/L) KCl Ringers solution The perfusion of MnCl_2(2 mmol/L)and TEA(10 mmol/L)also brought a decrease and an increase of APD. It was found that there exists a linear correlation between the Ca￣(2+)concentration and the APD value.