title: Increasing DHA and EPA concentrations prolong action potential durations and reduce transient outward potassium currents in rat ventricular myocytes.
abstract: The goal of this study was to determine the mechanisms of n-3 polyunsaturated fatty acids (n-3 PUFA) on anti-arrhythmias and prevention of sudden death. The calcium-tolerant Sprague-Dawley rat ventricular myocytes were isolated by enzyme digestion. Effects of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) on action potentials and transient outward potassium currents (I (to)) of epicardial ventricular myocytes were investigated using whole-cell patch clamp techniques. Action potential durations (APDs) and I (to) were observed in different concentrations of DHA and EPA. APD(25), APD(50), and APD(90) with 0.1 μmol/L DHA and EPA were prolonged less than 15% and 10%. However, APDs were prolonged in concentration-dependent manners when DHA and EPA were more than 1 μmol/L. APD(25), APD(50), and APD(90) were 7.7 ± 2.0, 21.2 ± 3.5, and 100.1 ± 9.8 ms respectively with 10 μmol/L DHA, and 7.2 ± 2.5, 12.8 ± 4.2, and 70.5 ± 10.7 ms respectively with 10 μmol/L EPA. I (to) currents were gradually reduced with the increased concentrations of DHA and EPA from 1 to 100 μmol/L, and their half-inhibited concentrations were 2.3 ± 0.2 and 3.8 ± 0.6 μmol/L. The results showed APDs were prolonged and I (to) current densities were gradually reduced with the increased concentrations of DHA and EPA. The anti-arrhythmia mechanisms of n-3 PUFA are complex, however, the effects of n-3 PUFA on action potentials and I (to) may be one of the important mechanisms.
authors.affiliation: Department of Cardiology, First Affiliated Hospital of Soochow University, Suzhou 215006, China.
authors.forename: Hong-Xia
authors.initials: HX
authors.lastname: Li
authors.forename: Ru-Xing
authors.initials: RX
authors.lastname: Wang
authors.forename: Xiao-Rong
authors.initials: XR
authors.lastname: Li
authors.forename: Tao
authors.initials: T
authors.lastname: Guo
authors.forename: Ying
authors.initials: Y
authors.lastname: Wu
authors.forename: Su-Xia
authors.initials: SX
authors.lastname: Guo
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Sun
authors.forename: Zhen-Yu
authors.initials: ZY
authors.lastname: Yang
authors.forename: Xiang-Jun
authors.initials: XJ
authors.lastname: Yang
authors.forename: Wen-Ping
authors.initials: WP
authors.lastname: Jiang
mesh_terms: D000200:Action Potentials / Q000187:drug effects*; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D004281:Docosahexaenoic Acids / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D015118:Eicosapentaenoic Acid / Q000494:pharmacology*; D006352:Heart Ventricles / Q000166:cytology / Q000187:drug effects*; D032383:Myocytes, Cardiac / Q000187:drug effects*; D018408:Patch-Clamp Techniques; D011188:Potassium / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D016276:Ventricular Function / Q000187:drug effects*
chemical_list: D000889:Anti-Arrhythmia Agents; D004281:Docosahexaenoic Acids; D015118:Eicosapentaenoic Acid; D011188:Potassium