六甲溴铵阻断交感神经元烟碱受体的机理

使用膜片钳全细胞记录技术，观察了六甲溴铵(C₆)对培养新生大鼠颈上交感节(SCG)神经元烟碱受体的阻断作用，并对其作用机理进行了研究. 本实验发现C₆对神经元烟碱受体的抑制作用具有明显的浓度依赖性和电压依赖性，可明显加速烟碱受体的失敏，提示C₆主要以阻断受体开放离子通道的方式拮抗烟碱受体.

Blocking mechanism of hexamethonium bromide on nicotinic acetylcholine receptors in cultured rat superior cervical ganglion neurons

The blocking effect of hexamethonium bromide (C₆) on neuronal nicotinic acetylcholine receptors (nAChRs) in cultured rat superior cervical ganglion was studied with the technique of whole-cell recording. It was found that: 1) C₆ blocked ganglionic nAChRs with a concentration and voltage-dependent manner. As the membrane potential was hyperpolarized from -30 mV to -90 mV, the inhibitory rates induced by 10 μmol·L^-1 C₆ on 50 μmol·L^-1 DMPP-evoked currents were significantly raised from 22±16％ to 72±13％. 2) C₆ could accelerate the desensitization of neuronal nAChRs. When the application time was prolonged to 15 s, C₆ not only depressed the amplitudes of DMPP-induced current, but also shortened the decay time constants of the currents remarkably. 3) When the mixture of DMPP and C₆ was applied for 6 times continuously with an interval time of 10 s, no significant differences were found among the inhibitory rates induced by 10 μmol ·L^-1 C₆ every time. The results suggest that C₆ may depress the ganglionic nAChRs by blocking the open channels, as well as accelerating the desensitization of nAChRs.