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本实验采用膜片箝技术观察了神经生长因子分化 5～ 10 d的大鼠肾上腺嗜铬细胞瘤 (PC12 )细胞上烟碱受体离子通道电流。在全细胞膜片箝条件下 ,当箝制电压为 -80 m V时 ,灌流乙酰胆碱 (ACh,3 0μmol/ L )诱发一内向电流 ,快速始发并衰减。此乙酰胆碱诱发电流 (IAch)随膜去极化和超级化而分别减小和增大 ,且被筒箭毒所阻断 ,可见此电流是由烟碱受体引起的。全细胞IACh呈较强的内向整流。其衰减相可被一双指数函数拟合 ,时间常数 (τ)分别在秒和分级。τf 对浓度的依赖性较τs强。 PC12细胞表面含有与交感神经元相似的烟碱受体 ,因此提供了一个交感神经元样的同源细胞株。它是研究神经烟碱受体调节的一个很好的模型系统
In this study, patch clamp technique was used to observe the ion channel currents of nicotinic receptors on adrenal pheochromocytoma (PC12) cells of 5 ~ 10 days after differentiation of nerve growth factor. Under the condition of whole-cell patch clamp, an inward current was induced by acetylcholine (ACh, 30μmol / L) at a clamping voltage of -80 mV, which rapidly initiated and decayed. This acetylcholine-induced current (IAch) decreases and increases with membrane depolarization and hyperfragmentation, respectively, and is blocked by myotubes, suggesting that this current is caused by nicotinic receptors. Whole cell IACh showed a strong inward rectifier. The decay phase can be fitted by a pair of exponential functions with time constants (τ) in seconds and graded, respectively. The dependence of τf on concentration is stronger than τs. The PC12 cell surface contains a nicotinic receptor similar to that of sympathetic neurons, thus providing a sympathetic neuronal-like cell line. It is a good model system for studying the regulation of neuronal nicotinic receptors