Ion flux changes induced by voltage clamping or by amphotericin B in the isolated urinary bladder of the trout.
Ion flux changes induced by voltage clamping or by amphotericin B in the isolated urinary bladder of the trout.
复制标题
鳟鱼离体膀胱中电压钳位或两性霉素 B 引起的离子通量变化。
DOI：
10.1113/jphysiol.1982.sp014139
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发表时间：
1982
期刊：
影响因子：
--
通讯作者：
B. Lahlou
中科院分区：
文献类型：
--
作者：
B. Fossat;B. Lahlou
1.在Ussing小室中，当双面浸泡在Ringer溶液中时，鲑鱼的离体尿囊电静默地将Na+和Cl-离子从粘膜输送到浆膜。在本实验中，通过使用电压钳技术或通过将粘膜侧提交给多烯抗生素两性霉素B，在这些条件下安装的上皮细胞上建立了一个电梯度。2.施加到组织上的稳定电位差在-40 mV和+40 mV之间，Na+和Cl-的单向通量(JMS和JSM)都随着电梯度的变化而变化。这表明，这些离子交换中相当大一部分是由于在低阻路径上的被动扩散。3.两性霉素B(40微克/毫升)应用于粘膜侧，立即引起较大的(高达50 mV，浆膜阳性)电位差，组织阻力持续降低。这些效应是严格依赖于Na+的，在哇巴因存在的情况下会减弱。因此，它们是由于Na+沿其穿过细胞顶膜的电化学梯度增加而被动进入。4.用葡萄糖酸等阴离子取代氯离子后，两性霉素B的作用增强。因此，在对照条件下观察到的氯-对诱导电位的分流效应似乎是由于阴离子途径上的氯-渗透性增加所致。通量数据表明，这条途径是跨细胞的。
1. When bathed with Ringer solutions on both sides in Ussing chambers, isolated urinary bladders of trout carry out an electrically silent transport of Na+ and Cl‐ ions from mucosa to serosa. In the present experiments, an electrical gradient was set up across the epithelium mounted under these conditions either by using a voltage‐clamp technique or by submitting the mucosal side to the polyene antibiotic Amphotericin B. 2. With stable potential differences between ‐40 and +40 mV applied to the tissue, both unidirectional fluxes (Jms and Jsm) for Na+ and for Cl‐ varied as a function of the electrical gradient. This indicates that a sizeable fraction of these ionic exchanges is due to passive diffusion across a low‐resistance pathway. 3. Amphotericin B (40 micrograms/ml.) applied to the mucosal side induced an immediate and large (up to 50 mV, serosa positive) potential difference and a sustained diminution in tissue resistance. These effects were strictly Na+‐dependent and were reduced in the presence of ouabain. Therefore they are due to increased passive entry of Na+ along its electrochemical gradient across the cellular apical membrane. 4. The effect of Amphotericin B was enhanced when Cl‐ was replaced by an impermeant anion such as gluconate. Therefore the shunting effect of Cl‐ on the induced potential observed in the control conditions appears to be due to an increase in Cl‐ permeability across an anion pathway. Flux data indicate that this pathway is transcellular.