Muscarinic activation of ionic currents measured by a new whole-cell recording method.
Muscarinic activation of ionic currents measured by a new whole-cell recording method.
复制标题
DOI：
10.1085/jgp.92.2.145
复制
发表时间：
1988-08
影响因子：
3.8
通讯作者：
Marty, A
中科院分区：
文献类型：
--
作者：
Horn, R;Marty, A
一种新方法被描述为全细胞记录的替代方法，以防止大鼠泪腺细胞对乙酰胆碱（ACh）的毒蕈碱反应“洗脱”。通过在膜片钳吸管中加入制霉菌素使细胞贴附膜片通透化，从而在吸管和细胞胞质之间提供电连续性，且不会丢失或改变维持对ACh反应所必需的胞质化合物。在这些细胞中进行正常的全细胞记录时，对ACh的反应（表现为钙激活的钾电流和氯电流的激活）持续约5分钟。使用制霉菌素方法，1小时后反应未减弱。结果表明，细胞外施加制霉菌素会导致细胞膜对阳离子的电导迅速且可逆地增加。在没有“洗脱”的情况下，我们能够获得ACh对钙激活钾电流影响的剂量 - 反应曲线。[ACh]的增加导致钾电流增加，在高于约1 microM ACh的浓度时出现明显饱和。ACh施加与钾电流激活之间的延迟与[ACh]成反比，在高[ACh]时达到0.7 - 1.0秒的最小值。
A new method is described as an alternative to whole-cell recording in order to prevent "wash-out" of the muscarinic response to acetylcholine (ACh) in rat lacrimal gland cells. The membrane of a cell-attached patch is permeabilized by nystatin in the patch pipette, thus providing electrical continuity between the pipette and the cytoplasm of the cell without the loss or alteration of cytoplasmic compounds necessary for the maintenance of the response to ACh. With normal whole-cell recording in these cells, the response to ACh, seen as the activation of Ca-activated K and Cl currents, lasts for approximately 5 min. With the nystatin method, the response is not diminished after 1 h. Nystatin, applied extracellularly, is shown to cause a rapid and reversible increase of membrane conductance to cations. In the absence of wash-out, we were able to obtain dose-response curves for the effect of ACh on Ca-activated K currents. An increase of [ACh] caused an increase in the K current, with apparent saturation at concentrations above approximately 1 microM ACh. The delay between ACh application and the activation of K current was inversely related to [ACh] and reached a minimum value of 0.7-1.0 s at high [ACh].