Lambert-Eaton syndrome IgG inhibits dihydropyridine-sensitive, slowly inactivating calcium channels in bovine adrenal chromaffin cells.
Lambert-Eaton syndrome IgG inhibits dihydropyridine-sensitive, slowly inactivating calcium channels in bovine adrenal chromaffin cells.
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Lambert-Eaton 综合征 IgG 抑制二氢吡啶敏感，缓慢失活牛肾上腺嗜铬细胞中的钙通道。
DOI：
10.1111/j.1749-6632.1993.tb22918.x
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发表时间：
1993
影响因子：
5.2
通讯作者：
Kim,YI
中科院分区：
文献类型：
--
作者：
Blandino,JK;Kim,YI
兰伯特-伊顿综合征 (LES) 是一种自身免疫性疾病，其特征是神经肌肉接头处胆碱能神经递质释放不足。','近 60% 的 LES 患者并发小细胞肺癌。 LES 动物被动转移研究、LES 运动神经末梢的冷冻骨折分析、3 以及自身抗体致病作用的膜片钳研究~~.~ 提供了令人信服的证据，表明 LES 的自身抗体与突触前膜中的电压依赖性钙通道发生交叉反应。牛肾上腺嗜铬 (BAC) 细胞被广泛用作交感神经元模型，最近被证明拥有两种类型的 Caz+ 通道。 6 本工作的目的是研究 LES IgG 对 BAC 细胞中两种类型的 Ca2+ 通道的特异性。BAC 细胞维持在 Dulbecco 改良的 Eagle 培养基中，其中含有 15% 热灭活马血清、5% CO2 和 95% 空气。首先将二氢吡啶（DHP）拮抗剂尼卡地平溶解在100%乙醇中，用蒸馏水稀释该溶液，然后添加到细胞中。将冻干的 o-芋螺毒素 GVIA (o-CgTx) 溶解在 1 mg/mL 牛血清白蛋白中，制成 10 pM 储备液。利用膜片钳技术，从 90 mV 的保持电位 (V,) 引出全细胞钙电流 (Ica)。移液器含有（以 mM 为单位）CaCl, 3、MgCl, 2、CsOHIHEPES 100 和 EGTA 30（pH= 7.2）；外部溶液由(mM)CaCl,5、MgCl,2、TEA-C1 10、HEPES 10和Tris-三氯乙酸酯110组成(pH＝7.4)。首先，我们根据失活动力学和药理学鉴定了 BAC 细胞中的两种类型的 CaZ+ 通道。结果总结如下。 (1) I, 灭活，初始瞬态为 169-+ 28 毫秒（n= 14 个细胞）的时间常数 (7;)，随后是长灭活成分 T,= 1393 2 129 ms（n= 14）。图 1A 显示了 Ca2+ 电流迹线及其基于 T 和 Tf 的分量（实线），用于去极化至 + 20 mV。在各种外部Ca2+浓度（5、2、0.8和0.4 rnM）下获得的Ica具有相似的7和rf。（2）10微摩尔尼卡地平将稳态Ica（在2秒结束时测量）降低81.5-C 4.7%（n=11），并且剩余成分以单指数衰减，T=280+-22ms（n=1） l)，类似于正常未处理细胞的T~(图1B和2)。在尼卡地平之后，我，在大多数细胞中可以
Lambert-Eaton syndrome (LES) is an autoimmune disorder characterized by an insufficient release of cholinergic neurotransmitters at the neuromuscular junction.’,’Nearly 60% of LES patients have concurrent small-cell lung cancer. The LES animal passive transfer studies,’freeze-fracture analysis of LES motor nerve terminal, 3 and patch-clamp studies of the pathogenic action of the autoantibodie~~.~ provided convincing evidence that the autoantibodies from LES cross-react with voltage-dependent calcium channels in the presynaptic membrane. Bovine adrenal chromaffin (BAC) cells are widely used as a model of sympathetic neurons and have recently been shown to possess two types of Caz+ channels. 6 The aim of the present work has been to investigate the specificity of LES IgG on the two types of Ca2+ channels in BAC cells.BAC cells were maintained in Dulbecco’s modified Eagle medium with 15% heat-inactivated horse serum at 5% COz and 95% air. The dihydropyridine (DHP) antagonist nicardipine was first dissolved in 100% ethanol, and the solution was diluted with distilled water before adding to the cells. Lyophilized o-conotoxin GVIA (o-CgTx) was dissolved in 1 mg/mL bovine serum albumin to make a 10 pM stock. Utilizing patch-clamp techniques, whole-cell calcium current (Ica) was elicited from a holding potential (V,) of-90 mV. The pipette contained (in mM) CaCl, 3, MgCl, 2, CsOHIHEPES 100, and EGTA 30 (pH= 7.2); and the external solution was composed of (mM) CaC1, 5, MgC1, 2, TEA-C1 10, HEPES 10, and Tris-trichloroacetate 110 (pH= 7.4). First we identified the two types of CaZ+ channels in BAC cells based on inactivation kinetics and pharmacology. Results are summarized as follows.(1) I,, inactivated with an initial transient described by a time constant (7;) of 169-+ 28 msec (n= 14 cells) followed by a long inactivating component, T,= 1393 2 129 ms (n= 14). FIGURE 1A shows a Ca2+ current trace and its components (solid lines) based on T, and Tf for a depolarization to+ 20 mV. Ica obtained at various external Ca2+ concentrations (5, 2, 0.8, and 0.4 rnM) had similar 7, and rf.(2) Ten micromolar nicardipine reduced steady-state Ica (measured at the end of 2 s) by 81.5-C 4.7%(n= ll), and the remaining component decayed with a single exponential, T= 280+-22 ms (n= 1 l), similar to the T~ of normal untreated cells (FIGURES 1B and 2). After nicardipine, I,, in most cells could