Effect of sevoflurane on the voltage-dependent sodium currents in a Lymnaea neuron

七氟醚对 Lymnaea 神经元电压依赖性钠电流的影响

• 批准号: 17591641
• 负责人: ONIZUKA Shin
• 金额: $ 2.37万
• 依托单位: University of Miyazaki
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-17591641/
• 关键词: Sevoflurane; Internal perfusion; Sodium currents; リドカイン; ナトリウムチャネル; セボフルラン; ナトリウム電流; パッチクランプ

Background : The voltage-dependent sodium currents (INa^+) are related to neuron excitability and anesthesia. To clarify the anesthetic mechanism of sevoflurane affecting INa^+, the effects of sevoflurane and lidocaine on INa^+ were compared using a neuron from Lymnaea stagnalis.Methods : The effects of sevoflurane and lidocaine on the membrane potential and INa+ were measured using current clamp and whole cell patch-clamp configuration. Sevoflurane was perfused either extra-cellularly or intra-cellularly. The amplitude of action potential, current voltage curves, and steady-state inactivation curves for INa+ were measured following in external and internal perfusion of sevoflurane.Results : External perfusion with sevoflurane suppressed the amplitude of the action potential [61.8 ± 7.6 (mV) in the controls, 43.8 ± 7.1 at 0.4 mM, 4.8 ± 3.6 at 2 mM, and 0.9 ± 0.8 at 4 mM], and INa^+ [80 ± 11% at 0.4 mM, 59 ± 12 % at 2 mM, and 48 ± 12 % at 4 mM] in a concentration-dependent manner. However, with internal perfusion, sevoflurane did not suppress these parameters. Conversely, internal perfusion of lidocaine suppressed INa+. The steady-state inactivation curves were not shifted by either external or internal perfusion of sevoflurane as lidocaine.Conclusion : Sevoflurane acts as an extra-cellular plug to suppress the voltage-dependent sodium currents.

背景：电压依赖性钠电流（INa^+）与神经元兴奋性和麻醉有关。为了阐明七氟醚对INa^+的麻醉作用机制，本研究采用海马神经元，比较了七氟醚和利多卡因对INa^+的影响。方法：采用电流钳和全细胞膜片钳结构，测定七氟醚和利多卡因对膜电位和INa+的影响。七氟醚分别灌注于细胞外和细胞内。测定七氟醚外灌注和内灌注后的动作电位幅值、电流电压曲线和稳态INa+失活曲线。结果：七氟醚体外灌注抑制动作电位幅值[对照组61.8±7.6 (mV)， 0.4 mM时为43.8±7.1,2mm时为4.8±3.6,4mm时为0.9±0.8],INa^+ [0.4 mM时为80±11%，2mm时为59±12%，4mm时为48±12%]呈浓度依赖性。然而，在内灌注时，七氟醚并没有抑制这些参数。相反，利多卡因内灌注抑制了INa+。七氟醚作为利多卡因外灌注或内灌注均未改变稳态失活曲线。结论：七氟醚可作为细胞外塞抑制电压依赖性钠电流。