Liu Zhaowei, Ren Guogang, Zhang Tao, Yang Zhuo
College of Medicine, The Key Laboratory of Bioactive Materials, Ministry of Education, Nankai University, Tianjin, China.
Toxicology. 2009 Oct 29;264(3):179-84. doi: 10.1016/j.tox.2009.08.005. Epub 2009 Aug 13.
Nano-sized materials are now being used in medicine, biotechnology, energy, and environmental technology. Although a wide and growing number of applications for nanomaterials exist, there are limited studies available on toxicity of nanoparticles for their human risk and environmental assessment. The aim of this study was to investigate the effects of silver nanoparticles (nano-Ag) on voltage-activated sodium currents in hippocampal CA1 neurons. Nano-Ag was tested at increasing concentrations (10(-6), 5 x 10(-6), 10(-5) g/ml). The research results showed that only nano-Ag (10(-5) g/ml) reduced the amplitude of voltage-gated sodium current (I(Na)). The nano-Ag particles produced a hyperpolarizing shift in the activation-voltage curve of I(Na) and also delayed the recovery of I(Na) from inactivation. Action potential properties and the pattern of repetitive firing were examined using whole cell current-clamp recordings. Peak amplitude and overshoot of the evoked single action potential were decreased and half-width was increased in the present of the 10(-5) g/ml nano-Ag solution, and the firing rate of repetitive firing had no change. The results suggest that nano-Ag may alter the action potential of hippocampal CA1 neurons by depressing voltage-gated sodium current.
纳米材料目前正应用于医学、生物技术、能源和环境技术领域。尽管纳米材料的应用广泛且不断增加，但关于纳米颗粒对人类风险和环境评估的毒性研究却很有限。本研究的目的是探讨银纳米颗粒（纳米银）对海马CA1神经元电压门控钠电流的影响。对纳米银在递增浓度（10^(-6)、5×10^(-6)、10^(-5) g/ml）下进行了测试。研究结果表明，只有纳米银（10^(-5) g/ml）降低了电压门控钠电流（I(Na)）的幅度。纳米银颗粒使I(Na)的激活电压曲线发生超极化偏移，并且还延迟了I(Na)从失活状态的恢复。使用全细胞电流钳记录来检查动作电位特性和重复放电模式。在10^(-5) g/ml纳米银溶液存在的情况下，诱发的单个动作电位的峰值幅度和超射降低，半宽度增加，并且重复放电的发放率没有变化。结果表明，纳米银可能通过抑制电压门控钠电流来改变海马CA1神经元的动作电位。
