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[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

Received: 2014-04-02　　Accepted: 2014-05-26

Corresponding author: 郝丽英　　E-mail: lyhao@mail.cmu.edu.cn

Citing This Article：

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).