Activation of Ca-dependent K channels by carbamoylcholine in rat lacrimal glands.
Activation of Ca-dependent K channels by carbamoylcholine in rat lacrimal glands.
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氨基甲酰胆碱在大鼠泪腺中激活 Ca 依赖性 K 通道。
DOI：
10.1073/pnas.81.2.611
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发表时间：
1984
影响因子：
11.1
通讯作者：
A. Marty
中科院分区：
文献类型：
--
作者：
A. Trautmann;A. Marty
使用膜片钳技术研究泪腺细胞膜的电特性[Hamill，O. P.，马蒂·A Neher，E.，Sakmann，B. & Sigworth，F.J.（1981）Pflügers Arch.391，85-100]。发现膜含有特定类型的电压和Ca 2+激活的K+通道（“BK通道”）。这些通道解释了在密封全细胞记录中获得的细胞电流-电压曲线的强整流。应用低浓度的氨基甲酰胆碱（CbmCho，0.5 μ M）激活BK通道。在阿托品（2 μ M）的存在下或当用强CaEGTA缓冲液透析细胞时，没有得到任何效果。后者的结果，与其他研究结果一起，表明CbmCho通过增加细胞内Ca 2+浓度对BK通道发挥作用。这种Ca 2+浓度的增加可能是通过从细胞质Ca 2+储存中释放而发生的，因为在细胞外Ca 2+不存在的情况下，反应仍然不受影响。在较高的CbmCho浓度（2 μ M）下，观察到内向电流，推测这是由另一种类型的Ca 2+调节通道的激活引起的。
Electrical properties of the membranes of lacrimal gland cells were investigated using patch-clamp techniques [Hamill, O.P., Marty A., Neher, E., Sakmann, B. & Sigworth, F.J. (1981) Pflügers Arch. 391, 85-100]. The membranes were found to contain a specific kind of voltage- and Ca2+ -activated K+ channel ("BK channels"). These channels account for the strong rectification of the cell current-voltage curve as obtained in tight-seal whole-cell recordings. Application of low concentrations of carbamoylcholine (CbmCho, 0.5 microM) activated the BK channels. No effect was obtained in the presence of atropine (2 microM) or when dialyzing the cell with a strong CaEGTA buffer. The latter result, together with other findings, suggests that CbmCho exerts its action on BK channels by increasing the intracellular Ca2+ concentration. This Ca2+ concentration increase presumably occurred via liberation from a cytoplasmic Ca2+ store, because the response remained unaffected in the absence of extracellular Ca2+. At higher CbmCho concentration (2 microM), an inward current was observed, which was assumed to result from activation of another type of Ca2+ -regulated channel.