二十二碳六烯酸对心室肌细胞动作电位和瞬间外向钾电流有影响。

Docosahexaenoic acid has influence on action potentials and transient outward potassium currents of ventricular myocytes.

机构信息

Department of Cardiology, Affiliated Hospital of Nanjing Medical University in Wuxi, China.

出版信息

Lipids Health Dis. 2010 Apr 17;9:39. doi: 10.1186/1476-511X-9-39.

DOI:10.1186/1476-511X-9-39

PMID:20398403

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC2862027/

Abstract

BACKGROUND

There are many reports about the anti-arrhythmic effects of omega-3 polyunsaturated fatty acids, however, the mechanisms are still not completely delineated. The purpose of this study was to investigate the characteristics of action potentials and transient outward potassium currents (Ito) of Sprague-Dawley rat ventricular myocytes and the effects of docosahexaenoic acid (DHA) on action potentials and Ito.

METHODS

The calcium-tolerant rat ventricular myocytes were isolated by enzyme digestion. Action potentials and Ito of epicardial, mid-cardial and endocardial ventricular myocytes were recorded by whole-cell patch clamp technique.

RESULTS

Action potential durations (APDs) were prolonged from epicardial to endocardial ventricular myocytes (P < 0.05). 2. Ito current densities were decreased from epicardial to endocardial ventricular myocytes, which were 59.50 +/- 15.99 pA/pF, 29.15 +/- 5.53 pA/pF, and 12.29 +/- 3.62 pA/pF, respectively at +70 mV test potential (P < 0.05). 3. APDs were gradually prolonged with the increase of DHA concentrations from 1 micromol/L to 100 micromol/L, however, APDs changes were not significant as DHA concentrations were in the range of 0 micromol/L to 1 micromol/L. 4. Ito currents were gradually reduced with the increase of DHA concentrations from 1 micromol/L to 100 micromol/L, and its half-inhibited concentration was 5.3 micromol/L. The results showed that there were regional differences in the distribution of action potentials and Ito in rat epicardial, mid-cardial and endocardial ventricular myocytes. APDs were prolonged and Ito current densities were gradually reduced with the increase of DHA concentrations.

CONCLUSION

The anti-arrhythmia mechanisms of DHA are complex, however, the effects of DHA on action potentials and Ito may be one of the important causes.

摘要

背景

有许多关于ω-3 多不饱和脂肪酸抗心律失常作用的报道，但机制尚不完全明确。本研究旨在探讨多不饱和脂肪酸对 Sprague-Dawley 大鼠心室肌细胞动作电位和瞬间外向钾电流（Ito）的作用特征。

方法

采用酶消化法分离钙耐受大鼠心室肌细胞。采用全细胞膜片钳技术记录心外膜、心肌中层和心内膜心室肌细胞的动作电位和 Ito。

结果

动作电位时程（APD）从心外膜向心内膜心室肌细胞逐渐延长（P<0.05）。2. Ito 电流密度从心外膜向心内膜心室肌细胞逐渐降低，分别为+70 mV 测试电位时的 59.50±15.99 pA/pF、29.15±5.53 pA/pF 和 12.29±3.62 pA/pF（P<0.05）。3. 随着 DHA 浓度从 1 μmol/L 增加到 100 μmol/L，APD 逐渐延长，但当 DHA 浓度在 0 μmol/L 到 1 μmol/L 范围内时，APD 变化不显著。4. Ito 电流随着 DHA 浓度从 1 μmol/L 增加到 100 μmol/L 逐渐降低，其半抑制浓度为 5.3 μmol/L。结果表明，大鼠心外膜、心肌中层和心内膜心室肌细胞之间存在动作电位和 Ito 分布的区域差异。APD 延长，Ito 电流密度逐渐降低，随着 DHA 浓度的增加。