Rane S G, Pollock J D
Department of Biological Sciences, Purdue University, West Lafayette, Indiana.
J Neurosci Res. 1994 Aug 1;38(5):590-8. doi: 10.1002/jnr.490380511.
The PC12 rat pheochromocytoma cell line is widely used to study neuronal differentiation by growth factors. In response to nerve growth factor (NGF) and basic fibroblast growth factor (bFGF), PC12 cells differentiate into sympathetic-like neurons and become electrically excitable. Using whole cell patch-clamp recording, with barium as a charge carrier, we looked at the effects of bFGF on calcium channel expression as reflected by changes in barium current amplitudes normalized to cell membrane area. Similar to the effect reported for NGF, we show that 7 day treatment with bFGF increased the barium current approximately 4-fold. The largest contributor to the increase in barium current with bFGF treatment is a 6-fold increase in the high threshold voltage activated omega-conotoxin sensitive barium current. Smaller increases in current produced by bFGF treatment of PC12 cells are observed for the dihydropyridine sensitive and dihydropyridine/conotoxin insensitive currents. The bFGF-induced increases in barium currents are dependent on tyrosine phosphorylation, since the effects of bFGF are blocked by genistein, a tyrosine kinase inhibitor. This system will ultimately be useful in understanding the signaling pathways that control calcium channel expression in response to growth factors.
PC12大鼠嗜铬细胞瘤细胞系被广泛用于研究生长因子诱导的神经元分化。在神经生长因子（NGF）和碱性成纤维细胞生长因子（bFGF）的作用下，PC12细胞分化为类交感神经元并变得具有电兴奋性。使用全细胞膜片钳记录技术，以钡离子作为载流子，我们通过将钡电流幅度归一化到细胞膜面积的变化来观察bFGF对钙通道表达的影响。与报道的NGF的作用相似，我们发现用bFGF处理7天可使钡电流增加约4倍。bFGF处理导致钡电流增加的最大贡献者是高阈值电压激活的ω-芋螺毒素敏感钡电流增加了6倍。对于二氢吡啶敏感和二氢吡啶/芋螺毒素不敏感电流，观察到bFGF处理PC12细胞后电流有较小增加。bFGF诱导的钡电流增加依赖于酪氨酸磷酸化，因为bFGF的作用被酪氨酸激酶抑制剂染料木黄酮所阻断。该系统最终将有助于理解响应生长因子控制钙通道表达的信号通路。
