摘要
目的 研究磁场对成肌细胞Na＋通道特性的影响.方法 实验分为空白对照和280 mT磁场作用组,将成肌细胞暴露于由磁铁产生的280 mT恒定磁场强度中,每组分别于12、36、60h后,应用全细胞膜片钳技术记录成肌细胞钠电流的激活、失活以及恢复曲线.结果 空白对照组中,Na＋通道开放的数目并不会随细胞培养时间的增加而发生改变.280 mT磁场作用组中,作用36 h,60h后峰电流密度值与其他组差异有统计学意义（n=10,P＜0.05）,280 mT 36 h组的半数最大激活电压为-25.39±0.37 mV、半数最大失活电压数值为-64.88±2.38 mV（n=10,P＜0.05）,280 mT 36 h,60 h失活后恢复时间常数减少,分别为8.49±0.16 ms和8.98±0.25ms（n=10,P＜0.05）.结论 磁场未改变Na＋内向电流具有快速激活和快速失活的特性.磁场作用下,Na＋通道开放的数目随时间的增加而增加,稳态激活曲线右移,Na＋通道难激活,但通道激活的速率没有改变.失活电压（绝对值）减小,通道不容易失活.通道从失活到恢复的过程加快.从动力学角度看,随着加磁时间的增加,磁场作用促进Na＋内流,Na＋开放和关闭的形式发生了改变.
Objective To examine the effects of 280 mT static magnetic field on sodium ion （Na＋） channel characteristics in skeletal myoblasts by using the whole-cell patch-clamp technique.Methods The cultured skeletal muscle cells were exposed to the 280mT static magnetic field for 12,36 and 60 hours,respectively,for the assessment of activation,inactivation and recovery curve of Na ＋ current by using the whole-cell patch-clamp technique.Results The number of open channel in the blank control group did not increase with time.In treatment group （exposed to 280 mT magnetic field）,the peak current density was significantly different at hours 36 and 60 （n=10,P〈0.05）.The half-maximum activated voltage of treatment group was （-25.39±0.37） mV and the half-maximum inactivation voltage （-64.88±2.38） mV （n=10,both P〈 0.05） at hour 36.In addition,the treatment group was associated with a shortened time of recovery at hours 36 and 60 [（8.49±0.16） ms and （8.98±0.25） ms,both P〈0.05].Conclusions The static magnetic field does not alter the characteristics of rapid activation and deactivation of Na＋ inward current.There is a trend towards an increased number of Na ＋ open channels with time when exposed to the static magnetic field,which results in a right-shift of the activation curve,suggesting the difficulty in channel activation with an unaltered velocity.The diminished absolute of inactivation voltage indicats a reduced likelihood of activation,which is accompanied by accelerated recovery from inactivated state.The static magnetic field kinetically facilitates the inward flow of Na＋ and leads to the opening and closure characteristics of Na＋ channel as the time advances.
出处
《中华生物医学工程杂志》
CAS
2013年第6期448-452,共5页
Chinese Journal of Biomedical Engineering
基金
国家自然科学基金面上项目（30700964）
无锡市医管中心发展基金（YGMll04）,（YGZQl304）
无锡市科技局项目（CSZ00N1216）
关键词
静磁场
Na+通道
膜片钳技术
成肌细胞
Static magnetic field
Na＋ channel
patch clamp technique
skeletal myoblast
