钙激活钾通道在黎芦碱致神经细胞损伤中的作用  

EFFECT OF THE Ca^(2+)-ACTIVATED K^+ CHANNEL IN VERATRIDINE-INDUCED CORTEX NEURONS DAMAGE

作　　者：赖晓晖[1] 朱文梅[1] 徐刚[2] 袁光固[1] 

机构地区：[1]四川大学华西医院神经内科,四川成都610041 [2]四川省人民医院,四川成都610072

出　　处：《中国应用生理学杂志》2005年第2期140-144,共5页Chinese Journal of Applied Physiology

摘　　要：目的:观察新生SD大鼠原代培养皮层神经元的钙激活钾通道(Kca)在黎芦碱致神经元损伤模型上的激活、抑制效应。方法:采用细胞贴附和内面向外两种膜片钳单通道记录方法记录新生SD大鼠原代培养皮层神经元的Kca电生理活动。结果:黎芦碱在胞外可激活Kca。在有钙浴液内,细胞贴附式,钳制膜电位+30mV,加入不同浓度黎芦碱(μmol/L:15、25、50、75),通道开放概率由0.005分别增加为0.014±0.003、0.085±0.010、0.132±0.016、0.059±0.006(P<0.01),在50μmol/L以内表现出浓度依赖性。无钙浴液内,细胞贴附式膜片上,钳制膜电位+50mV,随药物浓度(μmol/L)增加为15、40、60、100时,通道开放概率由0.005分别增加为0.014±0.010、0.113±0.006、0.141±0.004、0.295±0.009(P<0.05)。6例内面向外式膜片上,钳制膜电位+40mV,分别加入黎芦碱25μmol/L、50μmol/L3min后,通道开放概率由0.011±0.008分别增加为0.010±0.010、0.012±0.007(P>0.05)。黎芦碱在胞内Kca开放概率,平均开放/关闭时间,电流幅值均无明显变化。结论:黎芦碱通过影响胞内游离钙水平间接调节Kca,在缺血缺氧早期,胞内游离钙增高激活Kca开放。Aim: To observe the effects of Ca^(2+)-activated K^+ channel of primary cultured fetal SD rat cortex neurons in the veratridine triggered neuronal damage. Methods: The patch clamp technique of cell-attach and inside-out mode for these two kinds of single channel recordings were used. Results: Extracellular veratridine activated the Kca. In Ca^(2+) bath solution of cell-attach mode, Vp +30 mV, when the concentration(μmol/L) of veratridine were 15,25,50 and 75, the open probabilities of the channel were 0.014±0.003, (0.085)±0.010, 0.132±0.016 and 0.059±0.006(P<0.01) respectively. It appeared concentration-dependent within 50 μmol/L veratridine. In Ca^(2+) free bath solution of cell-attach mode, Vp=+50 mV, when the concentration(μmol/L) of veratridine were 15,40,60 and 100, the open probabilities of the channel were 0.014±0.010,0.113±0.006, 0.141±0.004 and 0.295±0.009(P<0.05) respectively. In the 6 cases of inside-out mode patch clamp, Vp=+40 mV, when the concentration of veratridine were 0, 25 μmol/L and 50 μmol/L, the open probabilities of the channel were 0.011±0.008,0.010±0.010 and 0.012±0.007(P>0.05) respectively. There were no significant difference on open probabilities, average open/close times and amplitudes at different intracellular veratridine concentration. Conclusion: Veratridine can affect the activation of the Kca channel through regulating the concentration of cytoplasmic free Ca^(2+). The opening of Kca activated by increase of intracellular Ca^(2+) during the early stage of anoxia may be a protection reaction of ischemic neurons.

关 键 词：神经元 钙激活钾通道 黎芦碱 膜片钳 

分 类 号：R741.05[医药卫生—神经病学与精神病学]