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

Wang Ru-Xing, Li Xiao-Rong, Guo Tao, Sun Li-Ping, Guo Su-Xia, Yang Zhen-Yu, Yang Xiang-Jun, Jiang, Jiang Wen-Ping

Description

There are many reports about the anti-arrhythmic effects of ω-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 (I to ) of Sprague-Dawley rat ventricular myocytes and the effects of docosahexaenoic acid (DHA) on action potentials and I to . Methods The calcium-tolerant rat ventricular myocytes were isolated by enzyme digestion. Action potentials and I to of epicardial, mid-cardial and endocardial ventricular myocytes were recorded by whole-cell patch clamp technique. Results 1. Action potential durations (APDs) were prolonged from epicardial to endocardial ventricular myocytes ( P < 0.05). 2. I to 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 μmol/L to 100 μmol/L, however, APDs changes were not significant as DHA concentrations were in the range of 0 μmol/L to 1 μmol/L. 4. I to currents were gradually reduced with the increase of DHA concentrations from 1 μmol/L to 100 μmol/L, and its half-inhibited concentration was 5.3 μmol/L. The results showed that there were regional differences in the distribution of action potentials and I to in rat epicardial, mid-cardial and endocardial ventricular myocytes. APDs were prolonged and I to 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 I to may be one of the important causes.

Informations

• Publié par: biomed
• Publié le: 01 janvier 2010
• Nombre de lectures: 5
• Langue: English

Extrait

Wanget al.Lipids in Health and Disease2010,9:39 http://www.lipidworld.com/content/9/1/39

R E S E A R C H Open Access Research Docosahexaenoic acid has influence on action potentials and transient outward potassium currents of ventricular myocytes

1 12 11 13 Ru-xing Wang, Xiao-rong Li*, Tao Guo, Li-ping Sun, Su-xia Guo, Zhen-Yu Yang, Xiang-Jun Yangand Wen- 3 ping Jiang

Background PUFAs on anti-arrhythmias and prevention of sudden Fatty acids, especially polyunsaturated fatty acidsdeath have been highlights [3-6]. It has been reported (PUFAs), play an important role in life and death of car-that PUFAs have the roles of anti-arrhythmias and pre- diac cells. Reasons are as follow:1.vention of malignant ventricular arrhythmias, however,they are essential fuels for mechanical, electrical, and synthetic activities of thethe mechanisms of which are still not completely delin- heart;2.levels are abnormally high in an ischemia theireated [7,8]. followed by a reperfusion; and3.dietary fish oil is appar-ω-3 PUFAs mainly include docosahexaenoic acid ently beneficial for heart function [1,2]. Therefore, the(DHA) and eicosapentaenoic acid (EPA). More attentions beneficial effects of PUFAs on cardiovascular diseases,have been paid to their beneficial effects on cardiovascu- such as fish oil, have been reported, and the effects oflar diseases in recent years, especially in their anti- arrhythmias and prevention of sudden cardiac death [9- 13]. However, most of these studies are clinical trials, and * Correspondence: [e-mail] Department of Cardiology, Affiliated Hospital of Nanjing Medical University in the mechanisms of which are still not completely known. 1 Wuxi and People's Hospital of Wuxi City, Wuxi 214023, China To investigate the mechanisms of ω-3 PUFAs on anti- Full list of author information is available at the end of the article © 2010 Wang et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons BioMedCentral Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.