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细胞内高镁对豚鼠心室肌细胞L-型钙通道活性的影响

赵美眯, 连雯雯, 孙睿, 王红梅, 封瑞, 胡慧媛, 孙雪菲, 郝丽英^*

中国医科大学药学院药物毒理教研室，沈阳 110001

摘要

本文旨在研究细胞内高镁对离体豚鼠心室肌细胞L-型钙通道的单通道门控特性的影响。急性酶消化法分离豚鼠心室肌细胞，应用膜片钳膜内向外单通道记录模式观察不同浓度细胞内镁([Mg2+]i)对心肌细胞L-型钙通道单通道电流的影响。结果显示，对照组([Mg2+]i 0.9 mmol/L)的心肌细胞L-型钙通道相对活性为(176.5 ± 34.1)%，而高镁组([Mg2+]i 8.1 mmol/L)钙通道相对活性显著降低至(64.8 ± 18.1)% (P < 0.05)。另外，8.1 mmol/L [Mg2+]i使心肌细胞L-型钙通道的平均开放时间缩短至对照组的约25% (P < 0.05)，但对通道平均关闭时间无明显影响。以上结果提示，细胞内高镁主要通过缩短通道平均开放时间抑制豚鼠心室肌细胞L-型钙通道的活性。

关键词： 镁离子; L-型钙通道; 心室肌细胞; 膜片钳技术; 平均开放时间

分类号：R96

[High intracellular Mg2+ affects the activities of L-type calcium channel in guinea- pig ventricular myocytes.] [Article in Chinese]

ZHAO Mei-Mi, LIAN Wen-Wen, SUN Rui, WANG Hong-Mei, FENG Rui, HU Hui-Yuan, SUN Xue-Fei, HAO Li-Ying*^*

Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang 110001, China

Abstract

This study is aimed to investigate the effects of high intracellular Mg²⁺ on L-type calcium channel in guinea-pig ventricular myocytes. The cardiomyocytes were acutely isolated with enzyme digestion method. By adopting inside-out configuration of patch clamp technique, single channel currents of the L-type calcium channel were recorded under different intracellular Mg²⁺ concentrations ([Mg²⁺]_i). In control group, which was treated with 0.9 mmol/L Mg²⁺, the relative activity of calcium channel was (176.5 ± 34.1)% (n = 7). When [Mg²⁺]_i was increased from 0.9 to 8.1 mmol/L (high Mg²⁺ group), the relative activities of calcium channel decreased to (64.8 ± 18.1)% (n = 6, P < 0.05). Moreover, under 8.1 mmol/L Mg²⁺, the mean open time of calcium channel was shortened to about 25% of that under control condition (P < 0.05), but the mean close time of calcium channel was not altered. These results suggest that high intracellular Mg²⁺ may inhibit the activities of L-type calcium channel, which is mainly due to the shortening of the mean open time of single L-type calcium channel.

Key words: Mg2+; L-type calcium channel; ventricular myocytes; patch clamp technique; mean open time

收稿日期：2014-04-02　　录用日期：2014-05-26

通讯作者：郝丽英　　E-mail: lyhao@mail.cmu.edu.cn

引用本文：

赵美眯, 连雯雯, 孙睿, 王红梅, 封瑞, 胡慧媛, 孙雪菲, 郝丽英. 细胞内高镁对豚鼠心室肌细胞L-型钙通道活性的影响[J]. 生理学报 2014; 66 (6): 718-722.

ZHAO Mei-Mi, LIAN Wen-Wen, SUN Rui, WANG Hong-Mei, FENG Rui, HU Hui-Yuan, SUN Xue-Fei, HAO Li-Ying*. [High intracellular Mg2+ affects the activities of L-type calcium channel in guinea- pig ventricular myocytes.] [Article in Chinese]. Acta Physiol Sin 2014; 66 (6): 718-722 (in Chinese with English abstract).