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依他尼酸抑制小鼠气管平滑肌收缩

赵晓雪, 陈微微, 陈媛媛, 柳梦苏, 李孟悦, 曹磊, 刘庆华^*

中南民族大学医学生物研究所，武陵山区特色资源植物种质保护与利用湖北省重点实验室，生命科学学院，武汉 430074

摘要

本研究旨在探讨依他尼酸(ethacrynic acid, EA)抑制气管平滑肌(airway smooth muscle, ASM)收缩的作用及其机制。利用BL-420S系统测量小鼠气管环张力，用全细胞膜片钳技术记录ASM细胞通道电流，用钙成像系统测量ASM细胞内Ca2+浓度。结果显示，EA剂量依赖性地抑制高-K+ (80 mmol/L)和乙酰胆碱(acetylcholine, ACh, 100 µmol/L)引起的小鼠气管环收缩，最大舒张百分比分别为(97.02 ± 1.56)%和(85.21 ± 0.03)%，半数有效浓度(median effective concentration, EC50)分别为(40.28 ± 2.20) µmol/L和(56.22 ± 7.62) µmol/L。EA分别降低高-K+ 和ACh诱导的细胞内Ca2+浓度，分别从0.40 ± 0.04降到0.16 ± 0.01，0.50 ± 0.01降到0.39 ± 0.01。此外，EA抑制ASM细胞L-型电压依赖钙通道(L-type voltage-dependent calcium channel, LVDCC)和钙库操纵的钙离子通道(store-operated calcium channel, SOCC)电流，以及高-K+和ACh引起的外Ca2+内流。同时，EA可以降低小鼠呼吸系统阻力(resistance of the respiratory system, Rrs)。以上结果提示，EA通过抑制小鼠ASM细胞LVDCC 和SOCC，抑制Ca2+的内流，降低细胞内Ca2+浓度，导致ASM舒张，提示EA是一种潜在的支气管扩张剂。

关键词： 气管平滑肌; L-型电压依赖钙通道; 钙库操纵的钙离子通道; 依他尼酸

分类号：R363

Ethacrynic acid inhibits airway smooth muscle contraction in mice

ZHAO Xiao-Xue, CHEN Wei-Wei, CHEN Yuan-Yuan, LIU Meng-Su, LI Meng-Yue, CAO Lei, LIU Qing-Hua^*

Institute for Medical Biology & Hubei Province Key Laboratory for Protection and Application of Special Plant Germplasm in Wuling Area of China; College of Life Sciences, South-Central University for Nationalities, Wuhan 430074, China

Abstract

The aim of this study was to investigate the inhibitory effect and the underlying mechanism of ethacrynic acid (EA) on the contraction in mice. BL-420S force measuring system was used to measure the tension of mouse tracheal rings. The whole cell patch clamp technique was utilized to record the channel currents of airway smooth muscle (ASM) cells. The calcium imaging system was used to determine the intracellular Ca2+ concentration ([Ca2+]i) in ASM cells. The results showed that EA significantly inhibited the high K+ (80 mmol/L) and acetylcholine (ACh, 100 µmol/L)-induced contraction of mouse tracheal rings in a dose-dependent manner. The maximal relaxation percentages were (97.02 ± 1.56)% and (85.21 ± 0.03)%, and the median effective concentrations were (40.28 ± 2.20) μmol/L and (56.22 ± 7.62) μmol/L, respectively. EA decreased the K+ and ACh-induced elevation of [Ca2+]i from 0.40 ± 0.04 to 0.16 ± 0.01 and from 0.50 ± 0.01 to 0.39 ± 0.01, respectively. In addition, EA inhibited L-type voltage-dependent calcium channel (LVDCC) and store-operated calcium channel (SOCC) currents in ASM cells, and Ca2+ influx. Moreover, EA decreased the resistance of the respiratory system (Rrs) in vivo in mice. These results indicated that EA inhibits LVDCC and SOCC, which results in termination of Ca2+ influx and decreases of [Ca2+]i, leading to relaxation of ASM. Taken together, EA might be a potential bronchodilator.

Key words: airway smooth muscle; L-type voltage-dependent calcium channel; store-operated calcium channel; ethacrynic acid

收稿日期：2019-03-19　　录用日期：2019-07-10

通讯作者：刘庆华　　E-mail: liu258q@yahoo.com

DOI: 10.13294/j.aps.2019.0056

引用本文：

赵晓雪, 陈微微, 陈媛媛, 柳梦苏, 李孟悦, 曹磊, 刘庆华. 依他尼酸抑制小鼠气管平滑肌收缩[J]. 生理学报 2019; 71 (6): 863-873.

ZHAO Xiao-Xue, CHEN Wei-Wei, CHEN Yuan-Yuan, LIU Meng-Su, LI Meng-Yue, CAO Lei, LIU Qing-Hua. Ethacrynic acid inhibits airway smooth muscle contraction in mice. Acta Physiol Sin 2019; 71 (6): 863-873 (in Chinese with English abstract).