Liu Wei, Zheng Jian-Quan, Liu Zhen-Wei, Li Li-Jun, Wan Qin, Liu Chuan-Gui
88 Hospital of Jinan Military Region, Taian 271000.
Sheng Li Xue Bao. 2002 Dec 25;54(6):497-500.
To compare the difference in action sites between mecamylamine (MEC) and hexamethonium (HEX) on nicotinic receptors of sympathetic neurons, we investigated the effects of MEC and HEX on the nicotine-induced currents in cultured superior cervical ganglion neurons by whole-cell patch clamp technique. The IC(50) of MEC and HEX for antagonizing the effect of 0.08 mmol/L nicotine was 0.0012 and 0.0095 mmol/L, respectively. Both MEC and HEX accelerated the desensitization of nicotinic receptors. Furthermore, by comparing their effects at holding potentials 30, 70 and 110 mV, it was indicated that their suppressing effect on the nicotine-induced currents was voltage-dependent. However, different from that of HEX, the inhibitory effect of MEC increased with administering the mixture of MEC and nicotine at intervals of 3 min, indicating a use-dependent effect of MEC. It is concluded that the action site of MEC on nicotinic receptors of sympathetic neurons is different from that of HEX.
为比较美加明（MEC）和六甲铵（HEX）在交感神经元烟碱样受体上作用位点的差异，我们采用全细胞膜片钳技术研究了MEC和HEX对培养的颈上神经节神经元中尼古丁诱导电流的影响。MEC和HEX拮抗0.08 mmol/L尼古丁作用的半数抑制浓度（IC50）分别为0.0012和0.0095 mmol/L。MEC和HEX均加速了烟碱样受体的脱敏。此外，通过比较它们在-30、70和110 mV钳制电位下的作用，表明它们对尼古丁诱导电流的抑制作用呈电压依赖性。然而，与HEX不同，MEC的抑制作用在以3分钟间隔给予MEC和尼古丁混合物时增强，表明MEC具有使用依赖性效应。结论是MEC在交感神经元烟碱样受体上的作用位点与HEX不同。
