U73122 INHIBITS PHOSPHOLIPASE C-DEPENDENT CALCIUM MOBILIZATION IN NEURONAL CELLS
U73122 INHIBITS PHOSPHOLIPASE C-DEPENDENT CALCIUM MOBILIZATION IN NEURONAL CELLS
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DOI：
10.1016/0006-8993(94)90927-x
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发表时间：
1994-04-11
期刊：
影响因子：
2.9
通讯作者：
THAYER, SA
中科院分区：
文献类型：
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作者：
JIN, WZ;LO, TM;THAYER, SA
氨基类固醇U73122抑制分化和未分化的NG108-15细胞以及原代培养的大鼠背根神经节（DRG）神经元中磷脂酶C （PLC）介导的细胞内Ca2+释放。1 μ M U73122阻断缓激素（BK）诱导的细胞内游离Ca2+浓度（[Ca2+](i)）的增加，用基于印度-1的双发射微荧光法在单细胞中测量。与之相近的结构类似物U73343则没有效果。U73122的作用具有时间和浓度依赖性。1 μ M药物在约3 min内产生一半最大抑制。暴露20分钟的IC50约为200 nM。在长达1小时的实验期间，该化合物的作用是不可逆的。用1 μ M U73122处理，而不是用U73343处理，产生了少量但显著的[Ca2+]增加(i)，这是由于Ca2+从细胞内储存中释放出来。目前尚不清楚这种[Ca2+](i)的增加是由于PLC的抑制还是直接作用于存储。在分化的NG108-15细胞中，U73122完全阻断了去极化诱导的Ca2+内流。相比之下，在DRG神经元中，U73122仅抑制轻微电压敏感的Ca2+通道。因此，我们警告说，U73122在最大限度阻断PLC所需的浓度下可能不具有选择性，并且U73122的选择性取决于细胞类型。总的来说，我们的结果与U73122在神经元细胞中抑制PLC的结果一致，并表明在适当的条件下，该化合物是研究肌醇1,4,5-三磷酸（IP3）介导的Ca2+动员的有用工具。
The aminosteroid U73122 inhibited phospholipase C (PLC)-mediated intracellular Ca2+ release in differentiated and undifferentiated NG108-15 cells, as well as rat dorsal root ganglion (DRG) neurons grown in primary culture. 1 mu M U73122 blocked bradykinin (BK)-induced increases in the intracellular free Ca2+ concentration ([Ca2+](i)) measured in single cells with indo-1-based dual emission microfluorimetry. A close structural analog, U73343, was without effect. The effects of U73122 were time and concentration-dependent. 1 mu M drug produced half maximal inhibition in approximately 3 min. The IC50 for a 20-min exposure was approximately 200 nM. The effects of the compound were irreversible for the duration of experiments as long as 1 h. Treatment with 1 mu M U73122, but not U73343 produced a small but significant increase in [Ca2+](i) which resulted from Ca2+ release from an intracellular store. It is not clear whether this [Ca2+](i) increase resulted from inhibition of PLC or an action on the store directly. In differentiated NG108-15 cells U73122 blocked completely depolarization-induced Ca2+ influx. In contrast, in DRG neurons U73122 inhibited only slightly voltage-sensitive Ca2+ channels. Thus, we caution that U73122 may not be selective at concentrations required for maximal block of PLC and that the selectivity of U73122 is dependent on cell type. Overall, our results are consistent with U73122 inhibiting PLC in neuronal cells and indicate that under the appropriate conditions, this compound is a useful tool for studying inositol 1,4,5-trisphosphate (IP3)-mediated Ca2+ mobilization.