摘要
用胰蛋白酶消化加吹打的方法急性分离SD大鼠（出生后7～14d）海马神经元，并用银染法对细胞进行验证。在膜片钳的全细胞模式下，记录细胞膜上钙离子通道的电生理活动，观察马桑内酯（Coriarialactone，CL）对电流幅度的影响。既有高电压激活钙电流（High voltage-activated calcium currents，HVA）又有低电压激活钙电流（Low voltage-activated calcium currents，LVA），HVA钙电流可分为以下三个部分：峰电流成分、持续的电流成分和瞬时的电流成分。其持续成分主要是L型钙电流。经20μl／ml和40m／ml的CL作用3min后，LVA、HVA峰值钙电流密度均增加（P〈0．05），这一作用具有一定的浓度依赖性。CL使海马神经元钙电流增大可以导致神经元兴奋性增高，引发神经元产生异常的癫痫样放电，这在CL致痫过程中起着重要的作用。
The hippscampal neurons of Sprague-Dawley rat （lOSt natal days 7 to 14） were acutely isolated using trypsin and mechanical dissociation. AgNO3 staining was performed to identify them. Vohage-dependent inward calcium currents were recorded by employing the patch-clamp technique in the whole-cell voltage-clamp mode. With different stimulation processes, we studied the ehanges of low voltage activated （LVA）} caldum currents, the transient and sustained components of high voltage-activated calcium currents （HVA） in the hippocampal neuron membrane. The effects of CL on the peak currents in the neuron membrane were assessed and analyzed. The main sustained components of HVA were L-type calcium currents. The HVA calcium currents were slowly inactivated in 300ms. The changes of the current amplitude of the sustained components of HVA were insignificant with the holding potential of - 100mV and - 50mV which indicated that the inactivation could be removed with the potential of - 50mV. The HVA calcium currents were eyoked by depolarizing voltage steps over the range of - 70mV to ＋ 50mV for 300ms with the holding potential of - 50mV and the threshold potential of - 40mV or so. The HVA and LVA calcium currents were evoked by the same stim- ulation with the holding potential of -100mV and the total calcium currents appeared at the potential of -60inV. The amplitude of peak currents significantly increased（P〈 0.05）. The transient LVA calcium currents as the peak calcium currents were evoked by depolarizing voltage steps over the range of - 70mV to - 30mV with the holding potential of - 100mV. Doth HVA and LVA calcium currents appeared over the range of - 30mV to ＋ 10mV. The HVA calcium currents mainly appeared above the membrane potential of ＋ 10inV. There was no obvious borderline between these components. About 3 minutes after the application of CL, the peak density of LVA calcium currents in 20 μl/ml and 40 μl/ml CL group increased respectively （75.56 % ± 23.09 % vs. 66.12 %±19.09 % ） （P 〈 0.05）. CL increased the peak density of HVA calcium currents in a concentration-dependent way, with enhancement by 18.15 % ± 4.98 % （P 〈 0.05） and 32.80 % ± 3.58 % （ P 〈 0.01 ） after the application of 20μl/ml and 40μl/ml CL. The effects of CL on the calcium currents will contribute to the enhanced excitability of hippocampal neurons, modulate some calcium-dependent processes and boost epileptic discharges. All of them play an important role in the CL-induced epileptogenesis.
出处
《生物医学工程学杂志》
EI
CAS
CSCD
北大核心
2008年第5期1053-1058,共6页
Journal of Biomedical Engineering
关键词
马桑内酯
海马神经元
钙电流
膜片钳
癫痫
Coriaria lactone（CL） Hippocampal neurons Calcium current Patch clamp Epilepsy
