Volonté C, Racker E
Section of Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, NY 14853.
J Neurochem. 1988 Oct;51(4):1163-8. doi: 10.1111/j.1471-4159.1988.tb03082.x.
LiCl stimulated the formation of inositol monophosphate in PC12 cells that had been exposed to nerve growth factor (NGF) for 4-5 days. Half-maximal accumulation was observed at approximately 8 mM LiCl. Stimulation of formation of inositol bisphosphate plus inositol trisphosphate was half-maximal at approximately 1 mM LiCl. With membranes isolated from PC12 cells differentiated with NGF, the hydrolysis of added phosphatidylinositol 4,5-bisphosphate (PIP2) was stimulated by LiCl in a biphasic manner, with the first stimulation half-maximal at approximately 0.7 mM and the second half-maximal at approximately 15 mM LiCl. The apparent Km for PIP2 was lowered in the presence of 1.1 mM LiCl from approximately 200 to approximately 70 microM. Membranes from cells grown in the absence of NGF did not respond to LiCl. Although observations with intact cells are difficult to interpret without ambiguity, the results obtained with isolated membranes support our interpretation of the stimulatory action of lithium in the intact PC12 cells.
氯化锂刺激了已暴露于神经生长因子（NGF）4至5天的PC12细胞中肌醇单磷酸的形成。在约8 mM氯化锂时观察到半数最大积累量。在约1 mM氯化锂时，肌醇二磷酸加肌醇三磷酸形成的刺激作用达到半数最大。用从经NGF分化的PC12细胞分离的膜，添加的磷脂酰肌醇4,5-二磷酸（PIP2）的水解受到氯化锂的双相刺激，第一次刺激的半数最大浓度约为0.7 mM，第二次刺激的半数最大浓度约为15 mM氯化锂。在1.1 mM氯化锂存在下，PIP2的表观Km从约200 microM降至约70 microM。在无NGF条件下生长的细胞的膜对氯化锂无反应。尽管在没有歧义的情况下很难解释完整细胞的观察结果，但从分离膜获得的结果支持了我们对锂在完整PC12细胞中的刺激作用的解释。
