Zwart R, Abraham D, Oortgiesen M, Vijverberg H P
Research Institute of Toxicology, Utrecht University, The Netherlands.
Brain Res. 1994 Aug 22;654(2):312-8. doi: 10.1016/0006-8993(94)90493-6.
Pharmacological characteristics of native neuronal nicotinic acetylcholine receptor-mediated ion currents in mouse N1E-115 neuroblastoma cells have been investigated by superfusion of voltage clamped cells with known concentrations of the agonists acetylcholine, nicotine and cytisine, and the antagonists alpha-bungarotoxin and neuronal bungarotoxin. The sensitivity of the nicotinic acetylcholine receptor for agonists followed the agonist potency rank-order: nicotine approximately acetylcholine >> cytisine. The EC50 values of acetylcholine and nicotine are 78 microM and 76 microM, respectively. Equal concentrations of acetylcholine and nicotine induce inward currents with approximately the same peak amplitude whereas cytisine induces much smaller inward currents. Acetylcholine-induced currents are unaffected by high concentrations of alpha-bungarotoxin. Conversely, at 10 and 90 nM neuronal bungarotoxin reduces the amplitude of the 1 mM acetylcholine-induced inward current to 47% and 11% of control values, respectively. Both the agonist potency rank-order and the differential sensitivity to snake toxins of nicotinic receptors in N1E-115 cells are consistent with the known pharmacological profile of alpha 4 beta 2 nicotinic receptors expressed in Xenopus oocytes and distinct from those of all other nicotinic acetylcholine receptors of known functional subunit compositions. All data indicate that the native nicotinic acetylcholine receptor in N1E-115 cells is an assembly of alpha 4 and beta 2 subunits, the putative major subtype of nicotinic acetylcholine receptor in the brain.
通过向电压钳制的小鼠N1E-115神经母细胞瘤细胞中灌注已知浓度的激动剂乙酰胆碱、尼古丁和金雀花碱，以及拮抗剂α-银环蛇毒素和神经型银环蛇毒素，研究了天然神经元烟碱型乙酰胆碱受体介导的离子电流的药理学特性。烟碱型乙酰胆碱受体对激动剂的敏感性遵循激动剂效力排序：尼古丁≈乙酰胆碱>>金雀花碱。乙酰胆碱和尼古丁的EC50值分别为78μM和76μM。等浓度的乙酰胆碱和尼古丁诱导的内向电流峰值幅度大致相同，而金雀花碱诱导的内向电流则小得多。乙酰胆碱诱导的电流不受高浓度α-银环蛇毒素的影响。相反，在10 nM和90 nM时，神经型银环蛇毒素分别将1 mM乙酰胆碱诱导的内向电流幅度降低至对照值的47%和11%。N1E-115细胞中烟碱型受体的激动剂效力排序和对蛇毒素的差异敏感性均与非洲爪蟾卵母细胞中表达的α4β2烟碱型受体的已知药理学特征一致，且与所有其他已知功能亚基组成的烟碱型乙酰胆碱受体不同。所有数据表明，N1E-115细胞中的天然烟碱型乙酰胆碱受体是α4和β2亚基的组合，这是大脑中烟碱型乙酰胆碱受体的主要亚型。
