Post stimulus effects of high frequency biphasic electrical current on a fibre's conductibility in isolated frog nerves
Post stimulus effects of high frequency biphasic electrical current on a fibre's conductibility in isolated frog nerves
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DOI：
10.1088/1741-2560/10/3/036024
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发表时间：
2013-06-01
影响因子：
4
通讯作者：
Qiu, Tianshuang
中科院分区：
文献类型：
--
作者：
Liu, Hailong;Zhu, Linlin;Qiu, Tianshuang
目标。高频双相电流在神经阻滞研究中被广泛应用。它们的安全边际很大程度上仍然未知，需要进行调查。的方法。本研究以牛蛙坐骨神经为实验对象，探讨HFB电流刺激后对神经传导性的影响。得到复合动作电位（CAPs）和差分动作电位（DCAPs，即对照动作电位减去HFB电流后的动作电位），并利用DCAPs的第一和第二向上分量N1和N2分量分析HFB电刺激的作用。主要的结果。首先，在完全阻断阈值下施加10 kHz的HFB电流5 s。在HFB电流作用下的60 s内，cap的最大振幅和传导速度显著降低（P < 0.02）。dcap显示出清晰的N1和N2组分，分别表明纤维正常电导的损失和新的延迟电导的出现。随着时间的推移，N1振幅的下降被认为是神经传导能力的恢复，呈现出两个不同的阶段：持续数秒的快速阶段和持续5分钟以上的缓慢阶段。进一步的测试表明，HFB刺激持续时间与N1振幅恢复周期之间存在线性关系。超阈值阻断不引起更高的N1振幅。的意义。这项研究表明，HFB电流导致刺激后神经传导能力的长期降低，这可能与潜在的神经损伤有关。一种可能的机制，集中在细胞内和轴周离子浓度的变化，被认为是神经传导性降低和潜在神经损伤的基础。当使用高频高频电流阻断神经传导时，应探索更谨慎、更安全的刺激方案。
Objective. High frequency biphasic (HFB) electrical currents are widely used in nerve blocking studies. Their safety margins largely remain unknown and need to be investigated. Approach. This study, exploring the post stimulus effects of HFB electrical currents on a nerve's conductibility, was performed on bullfrog sciatic nerves. Both compound action potentials (CAPs) and differential CAPs (DCAPs, i.e. control CAPs subtracted by CAPs following HFB currents) were obtained, and N1 and N2 components, which were the first and second upward components of DCAPs, were used for analyses of the effects introduced by HFB electrical stimulation. Main results. First, HFB currents of 10 kHz at a completely blocking threshold were applied for 5 s. The maximum amplitudes and conducting velocities of the CAPs were significantly (P < 0.02) decreased within the observed period (60 s) following HFB currents. The DCAPs displayed clear N1 and N2 components, demonstrating respectively the losses of the fibres' normal conductibility and the appearances of new delayed conductions. Decreases of N1 amplitudes along time, regarded as the recovery of the nerve's conductibility, exhibited two distinct phases: a fast one lasting several seconds and a slow one lasting longer than 5 min. Further tests showed a linear relationship between the HFB stimulation durations and recovering periods of N1 amplitudes. Supra-threshold blocking did not cause higher N1 amplitudes. Significance. This study indicates that HFB electrical currents lead to long lasting post stimulus reduction of a nerve's conductibility, which might relate to potential nerve injuries. A possible mechanism, focusing on changes in intracellular and periaxonal ionic concentrations, was proposed to underlie the reduction of the nerve's conductibility and potential nerve injuries. Greater caution and stimulation protocols with greater safety margins should be explored when utilizing HFB electrical current to block nerve conductions.